text:
Would moving a transaction from an old block to a new one allow more pruning?
At Pruning the branches in Merkle Tree Nick ODell writes "A leaf (transaction) can be pruned when all of its outputs have been spent." So I was thinking that if a transaction is one of the last few in a block, a miner can copy the transaction into the new block being mined.  That way the miner (and the rest of the network) no longer needs that block for validation, and it can be release into the ether.
Nick also wrote that Bitcoin core won't prune that way anyway because it operates "on the assumption that you download and validate all blocks."  I am exploring the reasons for this to see if they can be addressed without keeping everything.
The idea behind downloading the entire blockchain before starting pruning mode is that you want to make sure what you start with is valid.  The only known way to do that is to get the whole thing.  Or is it?  It seems that the ubiquity of the blockchain itself is matched by the ubiquity of the valid UTXO set, so if you get a valid UTXO set and it matches what every other node says, you're good to go.  Except for Sybil attacks, right?  Would such a successful Sybil attack also allow the blockchain itself to be faked?
One difficulty with my move-a-transaction approach is that when a new node is downloading the blockchain (however much of it is still needed) it will want to verify each block, and if block X is missing, then all the blocks that contain inputs that were created in block X can't be validated, if that means validating that the transactions in it are valid.  However, the blockheader itself can still be validated.  Block X's header can't be validated because it's contents are missing.  But isn't the fact that the hash from block X is required in block X+1 enough to trust that block X was valid, and that, therefore, so are blocks X+1, X+2, X+3, etc., all the way up to and including whatever block-being-validated contains a transaction that uses an output (presumably) created in block X?
When a transaction finally shows up that does spend an unspent output from the moved transaction, it won't be possible to validate it because block X is missing.  However, if the index that identifies which block holds which transaction were updated by the miner who moves the transaction, then this is simple to solve.
Would that index-update have to address all the immediate-child transactions of the moved transactions as well so that existing, previously valid transactions could still be validated by finding the source transaction in the newly mined block?  I don't think it's necessary to re-validate transactions that are in blocks with validated headers, is it?

This post is convoluted, and based on assumptions that should first be addressed separately, e.g. whether it is necessary to parse the complete blockchain, and reliance on a UTXO set provided by other users. Also, a copied transaction causes the including block to be invalid under current rules. Finally, the UTXO information is sufficient to validate an input, so you don't need "block X". That's why pruning as implemented works, and pruning as described never got followed-up on. In the result, I don't find the question as it is useful and suggest that it should be reworked and condensed.

I would like to thank you for responding to my suggestion by actually asking more questions and investigating the points. So often, I've been insulted or attacked for such feedback that what may seem as natural is a pleasant surprise.

This seems a lot of effort for absolutely no benefit.
In the Bitcoin pruning model you discard ALL those old blocks anyway, and JUST keep the utxo set. It doesn't matter whether a utxo is in an old block or a new block, you're still keeping it in the utxoset. Any blocks you keep around is merely for convenience and to assist other nodes that request those blocks.

The largest portion of bitcoiners who will contribute to the network is nearly always going to be far larger than the number who have all the data they need to help the newcomers. Those newcomers are facing ever larger downloads to get started. Pruning doesn't fix that. Pruning only fixed the persistent storage problem, which is relatively insignificant to the startup cost. My aim is to make participation easier to begin.

Much simpler solution: commit a proof of the utxoset in the block header every N blocks, and nodes make that utxoset available for download. The chain can be verified on block headers alone, and the utxoset can be verified based on the commitment in the header.

If block 414000 is the first one with that UTXO commitment then I'm guessing that at block 414550, it's safe to download less than the entire blockchain.  The newcomer determines whether or not the UTXO set they download (from source 1) is correct by waiting N blocks to make sure that the next commitment (which they get from Source 2) includes the changes those N blocks made.  If it fails that check, they start all over again, but they can't tell which of the two sources is the problem.  I guess that easily fixed by using multiple sources.

So headers would be downloaded from multiple sources to be cross-checked, and after N blocks the newcomer can verify that the transactions in them produce the correct new UTXO commitment.  I'm trying to identify ways to exploit the lack of validation of all the blocks before the last 550 because I like the idea, but I worry that it is giving up too much independent validation.

The simple answer is YES, but there are better solutions.  While it allows all transactions to be represented in more recent blocks, the presence of a transaction in a very old block is NOT what prevents the kind of pruning that I envisioned.  To make the earliest blocks unnecessary for validating the history of Bitcoin only requires proof that any UTXOs in them actually exist, and that they have not yet been spent.  A current UTXO Set would accomplish that, but it has to be proven. Jonas Schnelli suggested something very similar in February.


text:
Is buying bitcoin with paypal legal without laundering concerns?
I'm a software developer, and I want to make a website that allows users to sell bitcoin instantly for paypal cash without the hassle of an exchange - I don't even want to make a profit from it. The idea of it is to be a 100% fair exchange, instant, and no account/signup needed to encourage more people to use bitcoin.
Regardless, I was thinking last night and wondered if money laundering here is a concern? For example, a user stole bitcoins and sold it with my exchange. Is it the sellers responsibility to ensure funds are clean (since we are dealing with fiat cash)? What if someone buys bitcoin with dirty money and tries to sell the bitcoin on my exchange for clean the money? Would the seller be in trouble even though there is know way to know funds are legit? I am in the US.

Anybody who accepts a reversible payment (paypal, credit cards, even bank deposits to some extent) for an irreversible one will quickly find themselves defrauded on a massive scale. The rest of these questions are for a lawyer.

Please research the answers on this site like How can I buy Bitcoin via a Credit Card or Paypal? and these.

@eponymous I'm talking about selling though- How can a seller defraud a user? Only I can do a charge back. Of coarse, allowing users to buy bitcoin with paypal would be too risky.

@xFlare I misunderstood the question slightly, it's mostly a risk for the person receiving potentially stolen funds from paypal from you. PayPal chargebacks in particular can be extremely long reaching, there's not a solid way for customers to protect themselves against that.

@eponymous The opposite case is true because the OP is allowing people to sell their Bitcoin and is the one paying them with Paypal.

While I’m not an attorney, the website you describe would be considered a “money transmitter business” (MTB) which, in the US, falls under the jurisdiction of The Dept. Of Treasury FinCEN (Finacial Crimes Enforcement Network) which has regulations to prevent money laundering with strict anti-money laundering (AML) policies. You would need to register with FinCEN and comply with their regulations to legally perform such transactions on your website regarding AML/KYC (KYC is Know Your Customer). MTB laws also vary from state to state when it comes to cryptocurrency exchange for fiat money or vice versa. Just make sure to consult with a lawyer before you go live to protect yourself.

https://www.fincen.gov/sites/default/files/shared/FIN-2014-R002.pdf
This ruling deals with your exact question.

Welcome to Bitcoin.SE! Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference.

I also am not an attorney, from my perspective all you are doing is buying Bitcoins from the general public and you chose to use PayPal as your method of payment.
Consult an appropriately qualified and experienced attorney.

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text:
Need authoritative source for historic Bitcoin conversion prices from all exchanges
What are the authoritative sources for historic Bitcoin prices?
Ideally this will be an API for all major exchanges.

All historical data from any exchange available at Bitcoin Charts: Markets API

Historic Trade Data
Trade data is available as CSV, delayed by approx. 15 minutes. It will return the 2000 most recent trades.
  Format:
https://api.bitcoincharts.com/v1/trades.csv?symbol=SYMBOL[&start=UNIXTIME]
Returns CSV with columns: unixtime,price,amount
Example
Latest Kraken EUR trades:
  https://api.bitcoincharts.com/v1/trades.csv?symbol=krakenEUR

Thats a good starting point, but I don't know how "authoritative" it is since it seems to be a 3rd party.  I wonder how they collect the information in the first place.  Do you know if they simply screen-scrape the info?

@makerofthings7, BitcoinCharts is the main markets watch website, operator Nils Schneider aka tcatm - Bitcoin developer, owner of BitcoinWatch, creator and owner of BitcoinCharts, GPU mining software and JS web interface - https://en.bitcoin.it/wiki/People . It as authoritative as it gets in Bitcoin community. Every exchange listed on this site upload its historical data on the website - http://bitcoincharts.com/about/exchanges/

Many API endpoints included OHLC data from various exchanges can be found on

cryptowatch
cryptocompare

At the bottom of that linked google docs spreadsheet are instructions to download data from Mt Gox and many other Exchanges. Namely:

Go to this link: http://bitcoincharts.com/charts/mtgoxUSD#tgSzm1g10zm2g25zv
Click load raw data

This raw data only maintains daily prices.  This is probably the closing price for the day, but I can't be sure of that.
I'm not sure how bitcoin charts actually collects this information from the other providers.  I hope other

If you're looking for a one-stop shop for lots of different exchanges/markets, Coinigy provides historical crypto data. It's not free but probably one of the better sources.

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text:
Exchange-based vs over-the-counter (OTC)
I read an article about China ban on exchange, which mentions that

... the ban on exchange-based cryptocurrency trades will not extend to over-the-counter (OTC) transactions.

I am confused over the terms exchange-based and OTC. What are the differences between these two?

Exchange-based transactions, ;

Exchanges bring together brokers and dealers who buy and sell these objects. These various financial instruments can typically be sold either through the exchange, typically with the benefit of a clearinghouse to cover defaults, or over-the-counter (OTC), where there is typically less protection against counter-party risk from clearinghouses,
This is the case if you for example buy altcoins on Bittrex.com, Or poloniex.com All these transactions Are ""Exchange-based".

This means in the case of cryptocurrencies, that it is done through a third party, and you don't know the seller of the currency.
OTC transactions :

Over-the-counter (OTC) or off-exchange trading is done directly between two parties, without the supervision of an exchange. It is contrasted with exchange trading, which occurs via exchanges.

Transactions which are done on exchanges, take for example stocks being traded on stock exchange. Here the exchange and clearing house takes care of settlement. This gives very few options for trading with derivatives like future and options.
On the other hand, many a time, two parties may enter into over the counter transactions without going through exchanges and they could be presented with many new exotic derivatives that suits their need. Investment banks generally do it over various underlying assets.


text:
Technological contractor for an ICO legal advise
I was recently offered to hire my services to create and maintain a cryptocurrency.
My responsibilities would be to create a website and issue the tokens
While I think the project as some merit, I am concerned about any legal liability I could hold.
The contract I want to sign against will be an SLA (as to my understanding it will mitigate my legal risks as opposed to a partnership agreement).
The company that wants to hire me has declared to me that the ICO would be available to US residents and that I shouldn't worry about kyc or aml.
Also, the mentioned company states that its practices are legal and that it has a legal team on board.
I am aware this sounds a bit obscure, but these are all the details I can provide as to the signed NDA.
To what degree will I be accountable if the company breaks any law (not using a kyc to verify residence for example), or if one day the SEC decides that this ICO (or all ICOs for that matter) were illegal?

Welcome to Bitcoin SE!  This is a great question...but probably not for this stack exchange site.  Bitcoin SE is more about the technology of Bitcoin.  Luckily, there is a Law SE site (https://law.stackexchange.com/), which would probably be more suited for a legal question.

I duplicated the question in : link

We know that the referenced ICO would be available to US residents, but we do not know where the ICO is located. If it is located a Guatemala then I do not know that you even need to comply with US legislation.

While I think the project as some merit, I am concerned about any legal liability I could hold.

That's a good thing to think about.

The company that wants to hire me has declared to me that the ICO would be available to US residents and that I shouldn't worry about kyc or aml.

Do they mean that you shouldn't worry because someone else in the company is handling that, or because they're not going to do either of those things?
The latter is a warning sign, as discussed below.

Also, the mentioned company states that its practices are legal and that it has a legal team on board.

This means absolutely nothing.

Their legal team might be fictional. Ask for the names of their lawyers. Ask what jurisdiction they're licensed to practice law in. If they can't answer that, that's a bad sign.
Second, there are two reasons that people hire lawyers:

They want an accurate answer to a new legal question.
They want someone who will tell them what they want to hear.

If their legal team is real, and their legal team is unafraid to confront unpleasant truths, that's a good sign.

To what degree will I be accountable if the company breaks any law (not using a kyc to verify residence for example), or if one day the SEC decides that this ICO (or all ICOs for that matter) were illegal?

The SEC has already issued guidance on this subject. Basically, if the people buying the ICO are doing so for future profit, rather than for some immediate benefit, it's probably a security. (This is a good summary of the legal test.)
So your ICO is probably a security. Why does that matter? There are a bunch of federal laws that govern how securities may be sold and advertised. For example, someone who has $10,000 in total assets can't put all of their money into an experimental new security. Here's another example: securities firms must check that they're not selling to terrorists.
So at a very minimum, you're required to know who your customers are in order to comply with these rules.


text:
What’s the point of wannacry for exchanging Bitcoins to Monero?
At first glance, exchanging Bitcoin for Monero makes sense.  But why use Monero with an exchange, which is likely to help the police? (And which did.)
Monero transactions are private only on the block explorer. The sender has a key (view key) that allows one to view to whom and how much was sent.
So, what’s the point of using Monero in that case, rather than something that would resist investigators, like Zcash ?


text:
How do I buy Bitcoin with cash?
How do I buy Bitcoin with cash? I am Canadian, and have a lot of cash that I would like to convert to Bitcoin without using any banks. Can I do this?

Yes surely you can, Check out this website : https://localbitcoins.com/country/CA

In the most basic sense you can do this. One way is to find some one who owns Bitcoins and will sell them to you. Give them cash and have them send their Bitcoin to your wallet. You can even verify that you have received the btc.

Also there are full time exchanges many listed innthe above link from Adam.   These often require id proof

https://coinatmradar.com/ lists many ATM's, simply searching on Google for "Bitcoin ATM" gives you a map with locations, although you may get a lot of non bitcoin ATM's on there.

check localbitcoins for help, or some other sites like bitcoinworld/paxful/or the bitcointalk forum. But you need to pay some commision on it, I believe.

I knew about One Popular way to buy Bitcoin with cash that is Localbitcoins, there has a payment method to buy Bitcoin with cash.

I'm sure that is not the only way, but it is certainly a popular way...


text:
Does the Prospero X-1 have an USB port?
I have looked everywhere but cannot find out whether the Black Arrow Prospero X-1 has a USB port for connecting to a computer (and interfacing with miner to start mining). Does it have one?

You use the explorer and typing the ip adresse for the prospero, and then you get a web interface for setup.


text:
16x Presence Short (1x Riser)
I have an MSI Z77a-GD65 and I need to short one of the slots to get it to work. The MB was working fine with 5 GPUs until a couple of weeks ago when one of the slots stopped working. I know it's the slot because when I plug this GPU and riser into another slot it works and when I plug another GPU and riser into this slot it doesn't work.
So, I see posts about presence shorting a 1x slot. I found a page here that provides description of pins for all slots (1x, 4x, 8x, 16x).
http://pinouts.ru/Slots/pci_express_pinout.shtml
All slots except the 16x seems easy enough but the 16x has multiple presence detect, hot plug detect, hot plug present detect, etc pins. Any idea how to do a presence short?
I'm using a 1x to 16x powered riser.
Help will be truly appreciated.

This question appears to be off-topic because it is about repairing hardware. It might be a better fit for the superuser SE which deals with hardware topics.

@Murch, thanks. I may do that then. Presence shorts are actually directly related to mining, not so much about hardware repair. 1x risers frequently require presence shorts to get them to work and it's not a hardware defect so I was hoping someone here could help me out.

My bad, I wasn't aware of that. ;) Unfortunately, hardware questions don't seem to get good answers here quickly, we just had another a few days ago that has been just collecting orthogonal answers.

@Murch Thanks for the heads up :) I appreciate that. New here so still learning :) I'll try the bitcointalk forum as well.


text:
BIP0016 pay-to-scripthash transaction validation
BIP0016 says "Validation fails if there are any operations other than "push data" operations in the scriptSig".
What does it mean "push data operations"? OP_CHECKMULTISIG seems to be allowed but does not look like "push data" to me.

Note that the rule is about the scriptSig, not the scriptPubKey. The former contains the data that is passed to the latter.

What does it mean "push data operations"?

Push data operations are when a script pushes a byte vector into the stack. Examples are pushing signatures, public keys, or scripts. It excludes all script opcodes apart from OP_PUSHDATA1, OP_PUSHDATA2, OP_PUSHDATA3.

OP_CHECKMULTISIG seems to be allowed but does not look like "push data" to me.
  OP_CHECKMULTISIG is an opcode, however, since it's actually contained in a byte vector. You are pushing a full script to the stack, instead of just pushing the opcode.

So, if you look at a P2SH scriptSig:

...signatures... {scriptLength}{script}

You'll see that OP_CHECKMULTISIG is contained within {script} instead of being directly executed by whatever is parsing the scriptSig.

Like Pieter Wuille mentions, there is a difference between the scriptPubKey and the scriptSig script.
When a transaction is made, every output has it's own scriptPubKey script that specifies the condition to spend the output. Standard pay-to-address transactions have a script that can be interpreted as "sign this hash with the private key that corresponds to this address".
To spend the output, one must include it as an input in a new transaction. But to fulfil the output script, you will need to pass data as input to the script, mostly this is a signature. This data is passed in the scriptSig script.
The wiki page on the scripting concept will probably help you understand it.

Yes, I know how scripts work, but note this question is specifically about BIP0016. The question arised because OP_CHECKMULTISIG is in scriptSig (actually, in its inner serialized script) so it still applies. I guess the answer is: "the restriction only applies to the outer non-serialized scriptSig", is that correct?

You probably refer to this example scriptSig: [signature] {[pubkey] OP_CHECKSIG}. I think the curly brackets mean that the result of the operation between them is included. So it has 2 data elements. The signature and the result. But I'm not entirely sure of it, I didn't read the whole BIP. If the answer appears irrelevant, I'll remove it, just to thought you were confusing the two different script types.

The scriptSig contains 2 push operations: one with the signature, one with the serialized script. The scriptSig itself only contains pushes. Obviously, one of those pushes contains the actual script, but it's still just a push.

In the "Pay to Script Hash", ScriptSig looks like this

...signatures... {serialized script}

and ScriptPubKey is

OP_HASH160 [20-byte-hash-value] OP_EQUAL

You have to understand that {serialized script} in the ScriptSig is initially treated as a constant that just gets pushed onto the data stack. So even if {serialized script} is {[pubkey] OP_CHECKSIG}, as mentioned later in BIP16 as an example, it will not fail validation because the OP_CHECKSIG is not treated as an operation, it is just part of a constant.
Note that there are two validation steps in "Pay to Script Hash". The first step is where {serialized script} is treated as a constant and the rest of the script makes sure that the [20-byte-hash-value] is indeed the hash of {serialized script}.
The second validation step occurs when the first validation step succeeds, and
in the words of BIP16

{serialized script} is popped off the initial stack, and the transaction is validated again using the popped stack and the deserialized script as the scriptPubKey.

If you are still confused, I have written a beginner friendly article that explains how "Pay to Script Hash" works and walks through the execution of an example script in an article here:
http://kaykurokawa.blogspot.com/2014/07/scripting-in-bitcoin-part-2.html


text:
BIP0016 pay-to-scripthash transaction detection
BIP0016 acknowledges it works by "recognizing one 'special' form of scriptPubKey", so P2SH transactions are actually special cases.
What are the exact rules to detect these special cases?

The document you linked to provides all the information you need.
Specifically, for an output to be recognized as pay-to-scripthash, its scriptPubKey must match the format
OP_HASH160 [20-byte-hash-value] OP_EQUAL

The scriptSig of the redeeming input is validated using different rules:

Validation fails if there are any operations other than "push data" operations in the scriptSig.
Normal validation is done: an initial stack is created from the signatures and {serialized script}, and the hash of the script is computed and validation fails immediately if it does not match the hash in the outpoint.
{serialized script} is popped off the initial stack, and the transaction is validated again using the popped stack and the deserialized script as the scriptPubKey.

Older clients would accept such inputs, but they would not validate the included script. Therefore, the addition of these rules is a soft fork.


text:
Which release fixed CVE-2010-5141 (attacker can spend any coin)
This post by Mike Hearn relates an interesting bit of history:

When Bitcoin was first released, it contained two completely fatal bugs that made the entire system worthless. Fortunately, they were found and fixed before Bitcoin  actually had any serious value.
The first bug was that scripts were concatenated before being run instead of just using a shared stack. This meant that anyone could write a scriptSig that always evaluated to true and claim anyone elses coins. Fixed here in v0.3.2:
https://github.com/bitcoin/bitcoin/commit/73aa262647ff9948eaf95e83236ec323347e95d0

However, the link appears to point to the 0.3.7 update.
Looking at the diff, this update does appear to change the script interpreter in the way Mike outlined.
A search turned up very little on the 0.3.7 update. One hit was this question, which generated no responses:

I noticed that 0.3.7 is released on the website, but after searching the forums I can't find any information on what the changes are.  Never mind that the changes from version to version should be packaged with the download....
anyone care to clue me in on this one?

The CVE page, however, makes this claim:

On July 28 2010, two bugs were discovered and demonstrated on the test network. One exploited a bug in the transaction handling code and allowed an attacker to spend coins that they did not own. This was never exploited on the main network, and was fixed by Bitcoin version 0.3.5.

So, depending on the source you use, the release that fixed the bug was 0.3.2, 0.3.5, or 0.3.7.
Given that this was one of the worst bugs in Bitcoin's history, it seems like the documentation should be more consistent. Can someone point me to other sources that might help clear things up?

The 0.3.7 update does indeed fix the script execution bug that is being described, the vulnerable code below is removed and replaced with functions that execute the scriptSig and then the scriptPubKey on the same stack.
if (!EvalScript(txin.scriptSig + CScript(OP_CODESEPARATOR) + txout.scriptPubKey, txTo, nIn))

Previously what would happen is that the two script tapes were literally concatenated, then executed as one. The problem here is simply that we can use a trailing OP_PUSHDATA in the scriptSig push the entire scriptPubKey to the stack as a single data element rather than discrete opcodes. Our scriptSig would simply be a push opcode for the length of the scriptPubKey plus an OP_CODESEPERATOR. At the end of execution the only element remaining on the stack is not zero, so the evaluation returns true and we can spend any coins we like.

So the change allow only some standard scripts is not related to the issue?


text:
What miner can I use to mine litecoin with the scrypt hash function?
When I run cgminer for run it to mine ltc the parameter --scrypt, cgminer says that is not recognized option. So, cgminer does not work.
What miner can I use to mine litecoin with the scrypt hash function?

cgminer does not support scrypt mining, this was removed a long time ago.

what miner can i use for litecoin that you reccomend @Bitcoin ?

You can look at this table of software scrypt miners.
You don't mention whether you intend to try to use a CPU or GPU to mine. Towards the top of the list is sgminer (for GPU mining) and Pooler's cpuminer (for CPU mining). There are other choices listed there, but a number of them are just graphical frontends or are listed as no longer maintained.

thanks Joseph you think is best gpu or cpu mine for litecoin?

Well, if you have a GPU it should be better than a CPU in terms of how much hashing power it has. You can use a Litecoin mining calculator (that was just the first one that appeared on Google) and put in the hash rate, which you would get from the mining software when you try using it. That way you can figure out how much litecoins you can expect to receive.


text:
Can transactions scale sufficiently to compensate the diminishing block reward by fees?
Today, the bitcoin network is secured by massive computing power, which is expended in the process of mining. The miners are rewarded by newly mined bitcoins, plus transactions fees.
The security of the network relies on the computing power being so expensive, that no one group can afford to gain 51% share.
Eventually, the amount of newly mined bitcoins will diminish, and the mining  reward by itself would cause mining to become unprofitable.
Will the fees be able to pay the expenses for the huge expensive computing power?
I can see two extreme situations where it might work:
a) either the transaction fees will be astronomical
b) or there will have to be huge amount of transactions

option a) is clearly not viable, which leaves option b).
What would this mean for the bitcoin economy?
Will bitcoin need to become "high-velocity" money?
How could that be enforced? And how would we prevent the blockchain growing out of control?
Is my analysis correct?

possible duplicate of Will Bitcoin suffer from a mining Tragedy of the Commons when mining fees drop to zero?, How much will transaction fees eventually be?, Are there any studies into the size of the blockchain scaling over time?

Hey Martin, I changed the title, because it seemed to me that your question asks about whether "post mining" will actually occur, so I felt it was not the best description. I've also slightly edited a sentence, because it felt incomplete. Please feel free to further edit or revert any changes! :)

Or a combination of both. It looks like things like the Lightning Network will be there for micro payments and smaller amounts so that only larger transactions will be directly on the blockchain. For larger (and aggregate) transactions a bit more fee shouldn't be a problem (a). Also at some point the block size will likely be raised allowing for more transactions per block as well (b).
Either way your title is wrong: there is no post-mining world.

I thought the process is called mining, only when new bitcoins are being generated. But you seem to be saying, that transaction processing alone is also mining.

As far as i know everyone calls it mining regardless, wouldn't know what else to call it, certainly not just "validating" as everyone does that, not just miners. Also technically you could say that the coins that come out of the fees are still "fresh coins" as there is no regular transaction that send them to a miners address. Technically the fees are simply lost in transactions (in - out > 0) and then the miner is allowed to create fresh coins up to the total amount (or less). Also he still has to wait 100 blocks before he can spend them.


text:
this bitcoin address contains transactions which may be double spends. You should be extremely careful
i sent 0.4 btc to exchanger
and this transaction was sent 2 times from my wallet and spent to me 200$ (0.8 btc)
which i wanted only 0.4btc to send
transaction hash:
https://blockchain.info/address/15o8CfP4z8cWiZCp5euzNEqXjEFTyNF5Yb
funds are still missing from my blockchain wallet more than hour ago
and at this transaction at other place when clicking on "hash" i see:
" A conflicting transaction has been detected in our memory pool. The transaction hash displayed below may change. "
https://blockchain.info/tx/f3cf0d91fd678de0bbbf13aa69e87ab3c0e7c55c3aecb03c06ac78d5139fc2b6
so my funds are gone now? or will they come back

One of the transactions was rejected by blockchain.info and one got through.
There was a "malleability attack" going on just recently, that's probably the reason.  The attacker can take legitimate transactions, change the transaction ID (hash) and republish the transaction to the network.  See more at https://en.bitcoin.it/wiki/Transaction_Malleability - there is a BIP 62 in the pipeline dealing with this problem.
The attack is merely an annoyance, the recipient will never get twice the amount (800 mBTC in your case) through a malleability attack.


text:
setting up and verify a wallet under special circumstances
A friend of mine has a problem in verifying a wallet for the following reason.
Since about 40 years he has been denied a passport and a normal ID card by the german authorities after he handed in his old IDs after marriage. But it seems there is no chance to set up an BTC wallet that permits usual activities (buying resp. selling and transferring BTC.
Q: Is there any institution in the EU (using german or english language) that permits wallet on/with alternative identification and is at the same time trustworthy and has high level of integrity?
My friend would intend to buy 3 BTC and following per year one additional BTC for an indefinite period.
I would appreciate someone's help in this matter. Thank you.

It seems your friend is attempting to open an account at an online exchange, this is the general instance in which people new to Bitcoin try to make an initial purchase.
It is important to note that the account they are opening at an online exchange, is not just a bitcoin wallet, but also an exchange trading account. Currently the vast majority of online services do not make proper distinctions or delineations between the difference financial services they offer.
To create an account and associated set of keys to accept and transfer Bitcoin funds in the Bitcoin blockchain, one does not need to use a service, and may use any number of wallet software options. There are also free online services which do not require any identification to set up and host a wallet using their service.
I will not try to attempt to answer all the security related issues regarding wallet hosting services. This should be a separate area of inquiry for any new user of Bitcoin.
Any market, exchange, or trading platform where users can trade Bitcoin credits for national currencies, is managing transactions in those currencies, and will generally be attempting to comply with local laws respecting those transactions. It is at this point that these services are requiring identification of users, in order to comply with financial regulations.
The common practice of those looking to trade small amounts of Bitcoin credits for national currency, or vice versa, is to find ways to do so in person, rather than online. This usually done by finding someone to meet using an online service like LocalBitcoins.com or meetup.com and then meeting the person, or using a nearby Bitcoin ATM. In either case, small amounts of funds traded between the people or with the ATM are considered to be within legal limits of a non-reportable transaction. You may want to check your local regulations to see what those limits are.
It's good to keep in mind, for those who are new to Bitcoin, that there are two parts to any currency trade you are making for Bitcoin credits. The national currency transfer, and the Bitcoin funds transfer. The national currency transfer is the one that requires identification of users, generally speaking.


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Is the Bitcoin network slowly closing down?
Consider the following graph:
This chart shows the total number of hosts on the network that were connected in the previous 24 hour period. We collect this by listening to Address messages that are broadcast over the network and I got it from bitcoinstatus.rowit.co.uk. This graph and a number of other graphs on that site show significant reduction in the number of hosts on the network.
Does this mean that the Bitcoin network is slowly closing down? I can see that the graph seems to be quite level at the end, but the trend seems to be downwards.
Thank you jim618 for providing me with the link in this answer.

the chart appears to show a gradual flattening - the opposite of closing down. That is just from the view of the curve, not from me having any knowledge of the bitcoin network.

It could be that this host specifically is getting less connections, although that might not be the case.
There has been a similar drop in hashing power and stock price. The most likely cause of this is the lack of press-attention and a low amount of things you can do with Bitcoins. Another possible explanation is the increased usage of online-wallets reducing the need for locally running clients and therefore the total number of hosts connected.
Overall, no need to worry about the Bitcoin network closing down. In fact it seems to be about to grow faster again.
Some backing for my claims is here:
http://bitcoin.sipa.be/
Although it's hard to say anything from these charts

This, plus the death of casual mining.

With the blockchain getting large and taking up more disk space, fewer people are running the client locally.  Others are only launching the client when they plan to make or receive a transaction.

I'm among those who dabbled, found the "promise" of Bitcoins to be far less than they were hyped up to be, and decided to save the wear and tear on my GPU and call it a day.

Then by "promise" you mean "profit"? The mining part of the system was never meant to be profitable, only to be cost-neutral.

Actually the bitcoin network hash rate is up nearly 100% since June 2011.
That is a very misleading chart.
Here is a more accurate view. Notice the clear uptrend starting Dec 2011.
Source: https://blockchain.info/charts/hash-rate

It's not a misleading chart, it's just a different chart.  The first chart shows that less hosts are connecting, the 2nd shows the hash rate increasing.  That just means that hashing power is becoming more concentrated, with fewer hosts doing more hashing.


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How much would it cost for a government to undermine Bitcoins?
Articles by for example the Economist stating that Bitcoins are being used for drug trading (Silk Road), I believe that the biggest risk to Bitcoins is that a government will pull a stunt similar to Stuxnet. This was also the answer of David Schwartz to a previous question of mine.
Therefore, I believe that we should make a metric, similar to Bus Factor for software projects, which indicates risk of such an event with a single number. I propose that the metric should be called CSU (Cost of Secret Undermining). Later we could calculate the cost of undermining in other ways, like by banning businesses that accept bitcoins and so on, but that will be much harder.
Therefore, my question is: What is the current lowest CSU (Cost of Secret Undermining). This means, what is the cheapest way for someone (for example a government) to secretly undermine Bitcoins to the extent that Bitcoins are no longer useful as a medium of exchange, for example by utilizing the method suggested by David Schwartz. We should compare the number that we find with the current budget of the US fight against illegal drugs. Of course, the expected impact on the fight against illegal drugs is a deciding factor. Even though it will be very hard, we should try to estimate the development time needed to launch such an attack as this will be a cost the attacker would have to calculate with.
This question is related to this question, but now I would like to know the cost of undermining Bitcoins instead of just launching one single 51% attack.

Would this be a black project or one that is publicly acknowledged as being carried out?  It makes a big difference in the cost.  Also, would it be just one country or would it be a cartel of nations carrying out such an attack?

@StephenGornick A black one. The costs should then not be significantly affected by whether the undermining is carried out by a single or several organizations or governments.

It sure can.  If this hypothetical black ops deal requires cooperation from a foreign government (e.g., block port 8333 traffic) then there is more paid in bribe money than would be the cost of making an official request.

As I suggested in my Bitcoin master thesis, a 51% attack would cost in a bulk part of about 7 million dollars to execute. The figure will change depending on the technology used, the current difficulty and so forth. This option would make Bitcoin or any other Bitcoin-like currency useless.
However, if the USA goverment was to crack down on Bitcoin as a terrorist activity, it could detain any Bitcoin developer in the country indefinitely, which would probably be cheaper. This option would most likely generate a lot of backlash from the community, and could encourage other programmers to take over the project.

As you describe on page 42 in your thesis, those 7 million dollars only include the price of graphics cards, not other hardware needed, nor development costs of exploiting the 51% attack. Nor does it include variations in hashrate in the network, which might make it much cheaper to launch such an attack at certain times. Also, it might be possible to rent such hardware instead of buying it, which would make it significantly cheaper. If we said that the final price of launching such an attack would be 15-20 million, it really is peanuts for a government fighting illegal drugs.

@David, the cost is not much but it's still big enough and the task is too complicated to execute this attack in secrete, therefore US government would need a solid political agenda for that.

@Serith I would argue that this would be peanuts compared to developing Stuxnet. And it was certainly developed in secrecy. That was truly an amazing effort and I would guess that it involved much larger sums than what we are talking about here.

@David Well, I did say that it is in the bulk part of 7 million - as in probably within one order of magnitude. Probably you could get it cheaper actually if you used that as R&D money to create some high-end ASIC devices and then produce them in bulk. But yeah, I'm not a specialist at estimating such costs as I have no experience in it.

@Serith It wouldn't be too complicated to execute it in secrecy - 7 million is not that big of an expenditure in comparison to some military budget. You could introduce the machines gradually as some solo miners in various locations, and when you reach critical mass turn them from honest miners to attackers and I don't think anyone would expect it.

The NSA, as well as others, already have the computing power to achieve this. I'm sure no one but the NSA know's where the processing power of this fully armed and operational super computer is aimed.

@mindthemonkey Actually, those computers might not be the best choice to use against Bitcoin. Generally, supercomputers are used for fancy operations, like using floating point numbers and so forth, while Bitcoin just uses raw integers, making GPUs blow CPUs out of the water.

@ThePicahu Correct for most, but that doesn't mean they can't achieve it. If you check down the list you will see a number of them are based on Telsa 20 series coproccesors including the US. Even Google, Amazon, Intel, Ibm, Sun/Oracle, Microsoft probably have the compute power to achieve this.

I would guess that it would cost a lot more than $7 million for the US government to crack down on Bitcoin as a terrorist activity.

In certain situations it gets very easy:
If the NSA decides to send national security letters to developers they can be forced to do anything without being allowed to talk about it. Forcing them to 1: publish low quality updates and introduce backdoors, 2: dump-sell their Bitcoin over a predefined period should be quite effective.
This could make Bitcoins effectively useless in the short term. It might not work if the Americans don't manage to get a large enough part of the network to dump-sell, but I think there's sufficient wealth to push it below the cent range. Subsequently the crappy development should help it die a slow death.
This has a negligible cost.
Frankly I think becoming a horrible part of the community would be the most effective.
Team:
3 programmers
2 generic agents
The programmers create slow and abusive parts of the community software and have them be "exploited" or "hacked" frequently. Pushing media not to publish about Bitcoin, but when they do publish about these failures. They also continually publish expensive-to-process and large transactions in order to make running Bitcoin more expensive.
The generic agents attempt to shut down any Bitcoin businessman and/or buy out Bitcoin businesses and corrupt them.
There's also fake adverts created on Bitcoin trading sites, trying hard as they can to exploit the reputation systems.
These measures could make Bitcoin an extremely horrible-to-use system and should give it little extra exposure.
Naturally cracking existing Bitcoin businesses would also help.
Simply degrading the trust in Bitcoin whilst minimizing exposure would undermine Bitcoin. I do not think that secret undermining can stop ALL Bitcoin transactions.
This has a cost equal to 5 agents continuously.

This is not secret undermining.

It's stealthy. Can't destroy something without leaving traces so I figure it's about right. David's methods are also quite detectable, if you'd try. Do give an example of what "secret undermining" really should be.


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Could the EC2 infrastructure be used to efficiently launch a 51% attack?
This excellent answer from Serith states that one would need 31150 ATI 5870 graphics cards to launch a 51% attack. Amazon EC2 offers computers for rent for 2.10$ per hour. These instances have 2 x NVIDIA Tesla “Fermi” M2050 GPUs. Given that these are as fast as the ATI 5870 (I have absolutely no idea whether this is the case), and that Amazon has enough of these instances available, one should be able to launch a 51% attack for one hour for a mere 65415$. If the hash rate of the Bitcoin network varies over the time of the day or under such events as a power cut, then it could be cheaper.
Is this a potential threat to the Bitcoin network?

This is not paramount to the question, but I recall reading that the NVIDIA GPUs are not as efficient for mining as the ATIs for some reason.

Just to be clear, Amazon has added instance types through time and could conceivably add instance types with ATI cards.  Furthermore, a competitor to AWS could offer a similar service.

In response to numerous comments I've deleted my response and posed the question a different way Here

An NVIDIA Tesla “Fermi” M2050 is not as fast as an ATI 5870. According to the wiki, the NVIDIA card makes around 70Mh/s and the 5870 makes around 400Mh/s.
If they were similar and if Amazon had that amount of cards available for rent, then it would be possible. Just don't forget that you would be paying $65415 per hour to sustain an attack that will not give you that much power over the network. See this question for an explanation of what the attacker could do.

"If Amazon had that amount of cards available for rent" might not be a trivial condition.  I believe one has to petition them to launch more than 20 or so instances at once.

@Michael McGowan I agree, but the risk is that they do have it available or will have it available shortly. I know that big oil companies use services like EC2 to figure out where to bore the next hole. If they or similar companies are using GPUs to figure this out, then they or some of their competitors could have it available already.

Cluster GPU instances have been going for $0.70 during off peak times on the spot market. Obviously the spot price would rise if you tried to use that many, but if they had enough cards and if they would let you use them, the price could be closer to $21k. FYI EC2 is growing by leaps and bounds.

EC2 would be prohibitively expensive to attack bitcoin but would be well suited against so called "GPU unfriendly" block chains.  Against bitcoin EC most likely usage would be to "top off" an attackers hashing power.  If a hypothetical attacker built a massive hashing farm but was slightly short of 51% hashing power the attacker could use EC2 instances to push the attack "over top".
EC2 is ill suited as primary source of an attacker's hashing power because EC2 GPU prices are expensive, the GPU Amazon chose is poorly suited for hashing, and the number of instances is lmited (Amazon only has so many GPU instances). CPU instances are significantly cheaper but they have on average 1/50th the hashing power of average GPU which significantly increases the number of instances necessary to achieve 51% hashing power.
For so called "GPU-unfriendly" block chains (litecoin, tenebrix, solidcoin, etc) use of EC2 instances is far more efficient and economical.  Since these chains chose to exclude GPUs (a dubious decision) they have in effect removed the performance advantage between the hardware used by honest nodes and the most cost effective hardware available to attackers.  Each honest node is now significantly less powerful (being limited to on average a single CPU) and CPU power (in a variety of forms) is much cheaper and easily accessed by an attacker.  In essence these chains have commoditized the hardware used for hashing and as such left themselves vulnerable because large amounts of CPU hardware can be obtained for very cheap if only needed for a short period of time (like in a 51% attack).
Although the problem exists in all "GPU unfriendly" chains lets take a closer look at one chian, Litecoin.  Litecoin's hashing power is roughly 30MH/s.  To defeat that would require only 6000 Amazon Compute Units (virtual CPU roughly equivelent to a modern 1GHz Xeon CPU).  The largest Amazon instances have 30 compute units.  Thus it would only require 200 of the largest instances or roughly $300 per hour at current prices to achieve 51% of Litecoin's network hashing power.
Every other "GPU unfriendly" coin faces the same problem.  By excluding high performance GPU they have made it easier for an attacker to leverage large sources of easily obtained low cost CPU power putting the network at risk

In the future, it is likely that either Amazon or one of its competitors could offer GPUs that are better suited for hashing. I am, therefore, not sure that I agree with your opinion about how wise it is to exclude GPUs. It is a very interesting answer you have, nevertheless.


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What's the difference between a Bitcoin Wallet and a Bitcoin Exchange?
I was thinking about investing a small amount of money in Bitcoin: actually I'm having second thoughts about this, after all the fraud stories I've been told about on the Personal Finance site. However, that doesn't affect this question.
Reading this Investopedia article, I discovered that one should create a Bitcoin Wallet before buying Bitcoins on a Bitcoin Exchange such as Coinbase or Kraken. I don't understand why I should do that, isn't enough to download the Coinbase app, for example? Also, the link says that

While exchanges offer wallet capabilities to users, it’s not their primary business. Since wallets need to be kept safe and secure, exchanges do not encourage storing of Bitcoins for higher amounts or long periods of time. Hence, it is best to transfer your Bitcoins to a secure wallet.

What's the reason for that? If I buy stock options, no one would object to me keeping them invested for years. Then why can't I leave my investment on a Bitcoin Exchange for a long period?

Do I risk that the Exchange goes bankrupt?
Do I risk that someone hacks my account on the Exchange? If so, is that common?
Something else?

Basically, I want to understand if, for the sake of investing a small amount of money in Bitcoins, it makes sense to put my "pocket  money" in a Bitcoin Exchange and leave it there for a few years, or if the risk  of fraud/hacking is so high that I should not do that. Note that this has nothing to do with the volatility of the Bitcoin investment - I'm ok with making a risky investment (a gamble) since it's just very little money. But I'm not ok at all with having my money stolen, even if it's a small amount.

A bitcoin (or any crypto) wallet is simply a set of public/private keys. If you own the keys, you own any coins that those keys can access.
An exchange is very similar to a stock exchange. You exchange one asset for another. Exchanges come in many forms, such as decentralized (etherdelta), wallet-less (Shapeshift, Changelly), and the more traditional ones such as Bitfinex and Binance.
The first two kinds don't offer a wallet service. Coins are sent directly from a wallet you control to the exchange, and whatever you bought is sent directly to your wallet. These exchanges effectively offer no custodial service. It's like going shopping at a store. You take out cash from your wallet, give it to the store, and collect your goods and leave.
These exchanges, while around, are harder to use for the average user, and considerably slower due to the transactions needed to move crypto in and out. This results in less than ideal pricing and liquidity.
The regular exchanges solve this by offering both a wallet service and an exchange service. You can deposit coins and leave them in the exchange's custody, and then trade the amount you deposited instantly, without needing to make a transaction. Coins you buy are similarly credited to you on the exchange's platform, but are not truly in your control until you withdraw them to your own wallet. This is more akin to shopping at Amazon - You pay them, and you're told "Hey, you've paid me, and this item now belongs to you". But until the item is actually shipped to your own house (and thus put under your control), there is still a possibility that Amazon could default on that promise.
By using exchanges that act as wallets, you definitely run the risk that the exchange is fraudulent or can get hacked, or your account can be compromised. The general advice is that one only keeps funds they are actively trading on an exchange. If you plan on just buying a coin and keeping it for weeks/months/years, it is recommended you buy it and withdraw to a paper or hardware wallet.
For smaller amounts of money, you can also use programs such as Electrum to create a wallet that you control, and withdraw your coins to that.


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Using Bitcoin contracts to run a betting site without the need for deposits?
There are a couple of bitcoin betting sites, but they all seem to require making a deposit with them. Is it possible to somehow use the Bitcoin contract system to establish a distributed betting pool? Once the bet is decided one way or the other, the transactions would become active.
The problem of course is who decides which side won. That could be the betting site operator. This way, you still have to trust them enough to make a fair judgement call, but at least they cannot just take everyone's deposits and run. The worst they can do is declare the wrong side of the pool the winner. Or maybe stay inactive, thereby locking funds (though this could be fixed by a decision deadline in the original contract).
Or this could be distributed as well. Maybe a majority of pool members gets to decide by some kind of voting process (requires fair losers). Or the block chain miners get to decide by including one of the two possible transactions into the block, just like they decide on double-spending right now?
Does any of this seem feasible (and meaningful)?

https://en.bitcoin.it/wiki/Contracts talks about various kinds of contracts that can be made with non-standard transactions.  They make my head spin, but could perhaps be used to do what you want.  Do you accept the operator being able to declare their own bets the winner?  At least that way they can't just run off with the funds from existing bets between two third parties.

The betting site operator can participate in the betting pool through shills and declare the side his shills all bet on the winner. So you still are trusting the site operator with some of the deposits.

"Do you accept the operator being able to declare their own bets the winner?" Yes.

The underlying problem you are trying to solve is how to let a party that you don't trust to decide what happens with your money.   Since the betting site is acting as escrow until the event where payout occurs, a lot of money can accumulate.  If that money is in an untraceable, non-reversible currency then the risk that the operator disappears with the escrowed funds increases.
This problem occurs with any similar venture that has this characteristic where it holds onto its customer's money.

Giving the operator the power to control the identity of the recipient won't work, since he can participate himself and declare himself the winner. A majority vote also isn't too good because an attacker can make multiple entries, which is cheap to do if he knows he can guarantee a win.
It is necessary that the winner will be decided according to public data (such as the hash of a future block), and that the operator (or majority) will not be able to secure funds before sending payment to the agreed winner.
The only way I can think of is burn-escrow. Each participant sends a tentative payment to the operator which cannot be reversed, it can either be carried through or burned (with a deposit that incentivizes carrying through). Then the operator sends to the winner using his own funds. Then every participant forwards the payment. If the operator does not send to the winner, participants burn the payment and refuse to do business with the operator again.
There is some risk that the operator will be honest but participants will neglect to forward payments, or that the operator will be fraudulent but participants forward payments anyway to get the deposit. But with a properly calibrated deposit, these risks can be mitigated and entered into the pricing.


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Can Bitcoin mining hardware be used for other Crypto coins?
Can Bitcoin mining hardware be used for other Crypto coins?

You can do, if they are using the same mining algorithm. Bitcoin is using SHA256, here is a list of other coins using the same algorithm:
SHA256-Coins
Other coins like Litecoin are using the Scrypt algorithm, those are not compatible with bitcoin mining hardware.


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Unconfirmed Transaction using Blockchain.info wallet
I sent 0.08 BTC yesterday using the blockchain.info wallet on the iPhone.
It's been 24 hours and my money is still unsent; I really don't know what to do. It still says unconfirmed. Why is this? What can I do?
Transaction in question.

The previous transaction that you are using to spend the coin is also unconfirmed. See below. Looks like this is a problem with the blockchain wallet that you want to email their tech support about. It doesn't even seem to be broadcasting the transactions anymore.
https://blockchain.info/tx/2bf18c5ba2fe56f3d9ada4880181518e905f275bfc9826fdbebd07dca34f2ef2
If you want to fix the problem yourself, you could manually broadcast the transactions out by first getting the transaction hex :
https://blockchain.info/tx/2bf18c5ba2fe56f3d9ada4880181518e905f275bfc9826fdbebd07dca34f2ef2?format=hex
And using:
https://blockchain.info/pushtx


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Is Cointellect a scam?
I downloaded coin Miner from Cointellect.com on my PC and I started mining.
I have some questions:

Is the software a scam?
Has anyone gained real money from this software?

When I read forums, some people talk about scam and trojan viruses installed on their machines; others show money gained.

A good indicator of a scam is when they purport to have a business model that couldn't possibly make money. Also: "individual mining is now pointless. The solution is for free miners to unite." Pure nonsense.

Without looking at the site... Yeah is a scam. Check your pc for malware ( is reformat) and never use this PC or anything connected for bitcoin wallets.

This seems relevant: BCT: Cloudmining 101 (ponzi risk assessment)

Much of the evidence presented so far is weak. Addressing it, point-by-point:

The software is a virus.

If you look at the scan result, you see that half of the virus scanners detect the miner as Win32.BitCoinMiner.bAM or something similar. It's not surprising that a Bitcoin mining program would be detected as a bitcoin miner.

Company name similar to banking conglomerate but not that company

I'm not sure what banking conglomerate you're referring to, but that's probably a coincidence. The fact that I don't know what bank you're talking about means that there isn't a likelihood of confusion.

Your business model is unclear and you deflect all questions about it by saying "look at my blog."

I don't have a response to this.

You insult and make legal threats against anyone who characterizes you as scammers.

What are you supposed to do, not insult them?

From dnivi3:
I then proceeded to check if they actually had miner software on their webpage. They indeed do. And it looks fancy, way fancier than any other miner software out there. It has gimmicky graphics which no other miner software has, which leads me to believe that they want to lure new users to use their software because it is so fancy. Warning sign two: check.

Alternate explanation: they want to distinguish themselves from the dozens of other mining pools and cloud mining providers.

But, hey — wait — their account was created the 11th of July and their first tweet was posted the 11th of July as well. That’s suspicious considering most cryptocurrency/Bitcoin-startups have problems reaching that many followers in that short amount of time. The exchange I work, has existed for over a year and still has not crossed 1000 followers.

Spam twitter accounts need to follow normal accounts too, or Twitter will be able to find dozens of their customers just by identifying a single spam account and looking at everyone it's following.

After I’d had enough of looking through the Twitter-profile and the fake followers, I decided I’d do a Google-search for “Cointellect”. Turns out that this new and small mining startup has tons of references on the web. And, I am not just talking a few references and posts on the web, I am talking hundreds. Google turned up ten whole pages with forum-posts in foregin languages, obscure websites and some cryptocurrency blogs and newssites.

That's not surprising, because CoIntellect has an affiliate marketing program. Now, some of those marketers are going to straddle the line between recommending the service enthusiastically and spamming. It's unreasonable to expect CoIntellect to keep a leash on all of these users.

Additionally, there were other reviews of Cointellect on the web as well. They were all very similar, with the exact same screenshots. To me, they seemed like a copy-paste-job paid by Cointellect. See for yourself and judge if you think they are a copy-paste job or not.

There is a massive amount of plagiarism and blogspam in online journalism. The simplest explanation is that all of those blogs are copying each other.
thebitcoinnews often copies articles from The Daily Doge word for word. Example:

http://www.dailydoge.org/2014/10/29/norwegian-bitcoin-exchange-justcoin-closes-doors/
http://thebitcoinnews.com/2014/10/29/norwegian-bitcoin-exchange-justcoin-closes-doors/

So it seems that Sonera Corporative OU is bought from a online “ready made companies” seller. If this does not smell fishy, then what does?

Registering a corporation in many countries (possibly including estonia) is an enormous pain. It can be simpler to buy one that has already been made.

UPDATE 3 (10/09/2014): Just found some more interesting things. CoIntellect’s Twitter followers have suddenly dropped to 400 and the account has deleted literally all previous tweets. The tweet count is now on 18 and the follower count on exactly 400. I wonder how they got rid of all those followers. Messaged them to unfollow @CoIntellectFAQ? Hardly effective. Messaged the bot operators to get off their heels? Very effective, I’d assume. I think the latter is most likely to have happened.

Occam's Razor: Twitter noticed all of these bot accounts and deleted them. This is frequently done in waves to frustrate bot herders.

Update: It turns out it was a scam after all. ¯\(ツ)/¯

Yes, Cointellect is a scam.
See here:

http://cointelegraph.com/news/112424/is-cointellect-a-scam
https://bitcointalk.org/index.php?topic=789970.0
https://medium.com/@dnivi3/rolling-up-the-cointellect-scam-60787a30f9a4
http://www.bitcoinnotbombs.com/on-the-cointellect-cloudhashing-scam-and-the-currency-of-reputation/
http://www.1a20.com/category/cointellect-com/

Cloud mining by definition does not require locally installed software.

This is undoubtedly yet another scam. It's intent is the only question.
Your first port of call seems obvious; Google Is cointellect a scam?
Answer: yes.
Explanation:
Pooling the CPU resources of every miner using this software would be a fraction of the power for even the oldest ASICs.
As an analogy, the site is saying individuals need to dig an open cut mine with their spoons while mining rigs (ie 50ft tall trucks) are carting away pay dirt to process. Pool all the spoons you like, there's simply no feasibility of any reward - but assuming the improbable, if a block was mined, how is the ฿25 distributed? If you can't answer that then that's indicative of a scam.
As far as the "debate" about some users saying they've seen returns; this is how scammers operate. They use shills (fake positive reviewers) claiming profits which never occurred.
Whether the scam is fruitlessly using CPU to try and mine is possible, but it's astronomically more likely the software is a vector for Trojans to steal your Bitcoin. These types of malicious "mining" software are simply identifying newbie Bitcoin users, infiltrating the OS with a Trojan/RAT/keylogger, then stealing your wallet / private keys if/when they become available.
Assuming a Windows installation, you're basically screwed. The software likely already has your login info, passwords, private keys, credit card details; any and all are likely compromised. I'd immediately disconnect from the Internet and do a fresh install of your OS.
Please, research these things beforehand because so many of these services are popping up. Let's hope the Bitcoin Savings And Loan retroactive prosecution of running a Ponzi scheme sets a precedent and scares some would be scammers straight.
EDIT:

Virus analysis of software
SSL certificate owned by unknown
Company name similar to banking conglomerate but not that company

Take this info as you like. It's fact. Not libellous.

Tell that to the Congress we made our presentation at in Brussels Belgium, and our happy member's forum growing daily @ http://facebook.com/JoinCoIntellect
Then see our review of the conference on our post daily blog from there, along with our 24/7 support...
The definition of cloud mining? Simply put, cloud mining means using (generally) shared processing power run from remote data center which we do^ more ways than one, if you researched we are OPEN SOURCE explained HERE; http://cointellect.com/download/advanced

I've deleted the comments because they had gotten out of hand and were nonconstructive. You should get a chance to address accusations here, if it is done in a constructive way. Please put the relevant bits in the answer by editing it, not into comments. As it is, this answer does not explain sufficiently that your service is not a scam. I'd suggest that you explain how your business model works, address the criticisms other answers have given, and why your service is wrongly accused of being a scam, instead of attacking other users and linking arbitrary other things you have written.

*Dealt with elsewhere^ By all means try researching before allowing senseless ATTACKS... our integrity is intact, you are only doing yourself a dis-service with this thread. Google *Is cointellect a scam? and you find more than ONE answer! Including my answers to all the above, and then some!

And finally as we are the first to suggest research both Novice & Experts ALIKE - Membership does not require downloading our software or anyone else's - even though we are IN FACT Scan Verify ACCREDITED since Sept 2014, and NO REPORTS of wrong doing! Plus we use 3rd Party Processing Visa/MC & Paypal {One of the MOST STRICT payment processors online in favor of the BUYER. Any of the product or hash mining contract services we provide are GUARANTEED... bring on the scam phishers - you know who you are!

@Murch I have my previous comments and the latest saved on file in case you decide to delete these as well - you will be reported for slanderous online activity to appropriate ISP authorities!

As I already wrote above, I deleted the comments, because they didn't adhere to the purpose of comments: Please put the relevant information in the answer post, instead of the comments. You can edit your own post in order to do so. Comments are for constructive criticism, or clarification requests. As such they are considered transient and will be removed when obsolete or nonconstructive. Comments are not the right place to post answers, answers belong in answer posts.

Re Edits: having issues with mobile device. Will reply to you ASAP @Murch ... But IMO if CoIntellect have thousands of happy customers surely they're able to disprove allegations in a professional manner. Management would do well to call a meeting with sales, tech support and whoever is running their PR/marketing and sort out a less verbose diatribe using industry standards of grammar, spelling and common decency for their future press releases; it keeps things professional that way.

@Cointellect If you'd like to discuss this in a forum where it's more appropriate then please do so. Murch has done you a favor by deleting your highly unprofessional rants. Think of all the customers who will be put off by your demeanor. Keep it professional for your sake. Maybe just post transaction id for your mined blocks and the distribution therein or an independent source (not your blog or Facebook) which proves me wrong. It will certainly be a better way to go than abusing critics. I've been nothing but professional with you; "it's not personal, it's business": heard that saying?

@WoO Do yourself a favor and take your own advice - as I've stated clearly before deletion and after^ I base my comments on fact - not fiction! We have our facebook forums will suffice, this thread will only expose you - on the contrary^

@Murch, My comments had, and have everything to do the un-professional management of this thread, and I'm confident in my replies or would not write them to begin with for the general public to see... or few onlookers here! I don't consider deleting my comments a favor to say the least - you did yourself a favor, or at very least as WoO would say; *Me thinks?! end quote. You leave slanderous links but delete mine??!! You call that professional^

Oh and pardon me for pointing out *Mine your own business! Mine^ pun intended - is that professional enough?! WOOF
OOPS should this be a question or a comment?? @Murch we will highlight this thread in tonight's blog post!

Would you kindly have a look at [tour] for an overview how our site works, and then read my first comment again? I get the impression that it is not clear to you what I meant, and having an idea about the concept of SE might help you understanding my intention.

I understand perfectly well - as I was being sarcastic^ yet serious at the same time... Perhaps you should see my suggestions here, so you might understand me^ http://meta.bitcoin.stackexchange.com/a/235/5406

Look who's talking unprofessional...When I've yet to see any tangible evidence on the attacks displayed here, arbitrarily based on pure speculation! It would appear both the moderator, and scam accusers have trouble reading standard english, and or comments & answers to ATTACKS... If you don't like my responses, that is your problem! Calling any company a scam WITHOUT PROOF is libelous period. I've already given more response than is deserving here... only to have relevant comments, and defenses deleted - our forums will do fine thanks!

There's nothing wrong with our PR's responses! Scam phishers won't be tolerated, or bowed down to nonsensical metaphors^^^ The onus is upon the attackers to prove otherwise! That is the only industry standard that should be followed here or anywhere^^^^ My grammar is fine TY... short of a typo now and then. How we run our business is nobody's business but ours. BTW cointellect hasn't done ANY official press releases YET. Someone could use a lesson in etiquette and it's not me!! There is nothing professional in baseless scam claims presented here! You have been WARNED.

Every thing's OK. I make cointellect is not scam. I have proof and can withdraw via paypal.

my contract im using here, it not a scam

No referral links.

I'm confused. Are you an employee of CoIntellect? If not, why did you pick the username 'Cointellect Viet Nam'?

LOL i just name it to have ref =.= in viet nam,Im in Viet Nam how can i be an employee,i can speak vietnamese with you if you want ^^

LOL i just name it to have ref =.= in viet nam What does that mean?

Referral links still aren't ok.

This answer should probably be deleted. For one thing, it's not an answer. Of course scams permit people to withdraw, otherwise the scam wouldn't last five minutes. The question is whether they're actually mining in the amounts they say they are.

It's weird because when someone talk about cointellect is a scam (with basic claims, but without trying cointellect), every is upvoting. But when someone proof it's not scam with screenshots, everyone downvoting it. @DavidSchwartz I don't agree with you. I think this is a good answer because question is "Is Cointellect scam?", and this answer answering exactly this question.

@Eray Saying "no, it's not a scam" and then providing evidence that's equally consistent with it being a scam and it not being a scam is not an answer. Cointellect says they're mining. If they're actually mining as they say they are, it's not a scam. If they're just paying back investors their own money, it's a scam. The answer gives us no information either way but just reveals that the person answering doesn't understand the question. There's no proof given that Cointellect is doing what they say they are doing.


text:
Accepted shares won't go above 200
I'm new to Bitcoin mining, but I'd like to think I got things set up. I'm using guiminer, on slush's pool. For some reason, my accepted shares won't go above 200.
I have no stale shares but my accepted looks like 1597 (200).
Why is that?

A responder will probably need more info on what miner software/hardware you are using, and what pool you are contributing your shares to. Some screenshots, even, would be helpful.

I'm using the gui miner, and im using slush's pool.

Is this something you see in GUIminer, or when logged into slush's pool? Some screenshots would be helpful.

http://i.imgur.com/UTtEoX4.png

The number in parenthesis, is lower then the number to the left of it why is that? and why doesnt it go up further then 210?

The first number is the number of shares you have solved.
The second number is the number of pieces of work that you have recieved, but haven't begun solving. If it drops to 0, you aren't mining. Every ten minutes or so, these will become obselete, and you'll need new work, so there's not much point in requesting a bunch ahead of time.

Thanks, I appreciate it, sorry for the question i'm new to the bitcoin thing.


text:
Multiple coins on one server running MPOS/stratum
I've got an instance of MPOS and a stratum server running a single PeerCoin pool perfectly fine.
How do I go about adding a second pool to the same server?
I've tried to duplicate both the stratum server folders and the MPOS folders, then configure for a different coin. However, when when I browse to the other MPOS instance, for example www.mysite.com/MPOSSECONDSITE/public, it loads a blank page. What am I doing wrong?

Does the second stratum server work?

yes, it works great actually.  I'm just trying to add a second coin pool

Have you given proper permission to
www.mysite.com/MPOSSECONDSITE/public

If not, use this:
cd /home/username/mpos chown -R www-data templates/compile templates/cache logs


text:
Can you mine Monero using sgminer?
I've been mining Monero using my sgminer. I pointed it at https://moneropool.com/, but i when i visit the site to see my stats i see that my address is not found. Is my miner not working?

Are you aware that Monero uses CryptoNote as their hashing algorithm?

No you cannot. Monero uses a different PoW that is incompatible with sgminer, but also uses a different pool communication protocol that is Stratum-like but not actually Stratum.


text:
Transaction unconfirmed for hours
I need any help you can provide me regarding the transaction ea36f903db582e5b87c3618208cae2b28957521b8567f5d7934fc8b47a663bd8
It has been unconfirmed for more than 6 hours and I don't know what to do.
Thanks in advance to anyone who can help me.

The transaction is confirmed by now.

Your transaction can be seen here: https://blockchain.info/tx/ea36f903db582e5b87c3618208cae2b28957521b8567f5d7934fc8b47a663bd8
One of the inputs is address 1BPAcceeSNiNEHeeR1wEQDspvcq17jM142. It has an additional unconfirmed transaction at 671454f599c947cc01bf69defe68a6e59e869352006fb8b86df17dd51bc1d1fd. One of that transaction's inputs is 1KhqWzuRSB4cLsAnTtKjf8TGtY7HsNAdM4, which has an additional unconfirmed transaction at 8b780e2d3197ebdaf74688333fefc0fa83a11ff24f687423899354455881c14c. And here is the problem:

Your later transactions cannot complete until their inputs are confirmed. Your only option is to wait at this point.


text:
Is stack overflow reputation actually a Cryptocurrency?
In a way, it is already a currency since I can offer a bounty for my question.
So is it correct to call reputation points from StackExchange a Cryptocurrency?
If not, then why?

Related: http://bitcoin.stackexchange.com/questions/46408/can-the-system-of-votes-of-stack-exchange-be-considered-as-a-blockchain

A bounty buys additional advertisement for a question, it doesn't really buy an answer.

No, it is not accurate to call the reputation system a cryptocurrency.
Cryptocurrencies use a distributed form of updating the ledger of ownership, not controlled by any one person. Stack Exchange reputation points are just an online point system maintained and controlled by the Stack Exchange company. The two are very different.
Cryptocurrencies also typically have a blockchain, and are transferrable at any time between any two persons. With SE Rep, you can only transfer if you do a bounty. And SE rep can be created out of thin air for someone answering a question well. Cryptocurrencies have a supply that is carefully controlled by code, and can only be created by solving a block.

No, I would say that it is not a cryptocurrency.  However, I can see where there's an argument that it is.
What is usually referred to as "crytpocurrency" is a currency enforced by cryptography.  Since Bitcoin, this term is often blurred with "decentralized currency", which SE rep is certainly not.  StackExchange reputation is in a sense enforced by cryptography, since cryptography is used in the authentication mechanism of the site.
To me, the difference is not in the centralization nor the use of cryptography, but rather the idea that rep is a currency.  Yes, you can set bounties with it...but that's it.  It can only be spent with a single institution, and even more restrictive than that, on a single offering of that institution.  This means it is less of a currency than a gift certificate.  It cannot be transfered to someone in a will, nor is there any exchange for converting it to other currencies.  It cannot even be purchased in the same way that MMORPG currency can be purchased from "gold farmers".
Reputation simply does not meet the criteria for being a true currency.
Here's a couple of nice meta conversations about the topic of buying/selling SE rep:
https://meta.stackexchange.com/questions/30982/how-to-convert-your-stack-overflows-reputation-into-money
https://meta.stackexchange.com/questions/204719/is-reputation-the-currency-of-stack-overflow

It would be correct to call StackOverflow points a "digital currency", but not a "cryptocurrency" as they don't employ cryptography, blockchain or decentralization -- which are hallmarks of cryptocurrencies.
But, as you pointed out, SO points are digital and can be used to "purchase" the service of online answers.
So they do meet the definition of a digital currency.


text:
Beginner's Explanation
I'm interested in learning more about how bitcoin, mining, and blockchain technology work. I'm a student and don't have a strong background in computing, and I'm looking for a layman's explanation of a few basic, yet critical questions surrounding the currency and the technology behind it. I plan on sharing the results with other interested students who want to understand more about this important concept.

Miners receive 25 Bitcoins every time they create a hash (is this accurate?)- where do the coins they receive come from - are they fabricated or do they already exist somewhere? What I'm trying to understand is how the supply of currency changes - are there a fixed number of Bitcoins in existence, or is currency simply "created" whenever a miner updates the blockchain? As time goes on, will the money supply expand at some rate roughly equal to the growth in transactions - is this kind of like how the supply of fiat money in most economies has grown over time?
Is there a single blockchain for Bitcoin, which contains a record of all the transactions made since the first transaction? If so, does that mean that the chain will just keep getting longer and longer as more transactions are recorded? If Bitcoin increases in usage and popularity, won't the blockchain continue to grow (maybe exponentially) and will that add to the complexity of the miner's task?
This may be too complex to explain to an average person like me, but how do transactions actually get coded/added to the blockchain? I know that it requires brute force computing power and is based off of cryptography, but that's really the extent of my knowledge... If I wish to transfer 100 coins to my friend, that simple transaction must be captured somehow and translated into the chain - but how is this translation performed? Is there a constantly-changing key that has to be iteratively solved for by the miners? If a person were to "look" at the blockchain (I assume this is possible) - what would it look like, just a seemingly random collection of characters?

I'll stop there, as I'm sure there aren't simple answers to these questions and I'm sure I've misused/misinterpreted terminology and how these things actually work. Many thanks to all who read my question, and special thanks to anyone who is willing to answer one or more of my questions. If there is a better forum for me to post beginner's questions like the ones above, I'd certainly like to know that as well.

Hi Robert, thanks for your interest and welcome to Bitcoin.Stackexchange. I'm on my way to bed, so I'll be brief: For 1) please check out Where do bitcoins come from and what gives them value? and How many bitcoins will there eventually be?.

For 2) see Is there a (potential) “Blockchain size problem”, and what solutions are available?, the difficulty for miners comes from the competition with other miners, the task's difficulty is not influenced by the size of the blockchain. For 3) see What exactly is Mining?

Actually, it would be best, if you split each of your questions to it's own post. Our format doesn't work very well, when people ask too many questions in one post. You could make about five good specific question posts from this one! ;) However, as you can see all of these topics have been asked about before. ;) Perhaps this list of frequently questions we have would be of interest to you: I am new to Bitcoin, how can I get started?

Murch - thank you! I'm new and didn't understand how best to ask my question. I'll keep your comments in mind for the. Thank you for your suggestions - I've begun to take a look, and I think this is what my peers and I have been looking for. This is a great place for us to start. Thank you!

I'm glad you're finding our site helpful. So, here is what is going to happen: As I was trying to point out yesterday your question post has too many different topics in it. That makes it very hard for us to give complete answers and to have several good answers on each of your questions. Our procedure is to close this type of questions as too broad.

There are already a few close votes on it, and I will put it on hold after this comment. This does not mean that we don't want your questions, rather it means that the way you are asking your questions here doesn't work well on our site. Could you please do me the favor to split them up? Just cut and paste sections of this question above into new question posts and give each a speaking title. You can ask as many questions as you want. If you want any help, I'll be in the chat for the next few hours. I'll be inviting you to join there.

Thank you, Murch. After being on the site for a day and reading a number of other questions, I have a better sense for how things work. I'll split up my questions now as you've instructed. Thanks again!

Yay, very glad to hear that. :)

I would recommend reading 'Mastering Bitcoin: Unlocking Digital Cryptocurrencies', by Andreas M. Antonopoulos.  This book answers all of the questions that you posed, and more, in a very understandable way.

He said:  "I'm a student and don't have a strong background in computing" so I think this book is too high level

Thank you - great suggestion, and although I don't have a computer science background, this is certainly a helpful place to start. Any suggestions for other publications are gratefully accepted!

After reading the book, I disrecommend it. It reads like a raw hex dump of Bitcoin blocks and transactions, as well as dumps of command lines on how to use the official Bitcoin client. It doesn't provide much explanation of why things are designed a particular way.

I disagree.  Yes, parts of the book are more technical and contain code, diagrams, dumps, etc.  But, I found that the book contains very clear descriptions in plain English on how all aspects of the Bitcoin protocol and network work.  I don't have any relation with the author or publisher, but I highly recommend this book, and 52 customer reviews on Amazon gave it an average rating of 4.7 out of 5.0.

They are generated every 10 minutes and sent to the pool that have won and cyphered the lastest block.
Yes
There's a "public key cryptography" (not a native english speaker) mechanism involved

Thank you! With regard to #1 (where do the "mined" coins come from), is this by design so that the use of bitcoin can grow without adding significant volatility to its value as a currency? If there were only a fixed number of coins in circulation, as more people used bitcoin its value would skyrocket up. Does growing the supply of coins alongside transactions serve to stabilize the supply - and by extension - the value of a bitcoin?

Supply of coins is limited. It will hit 21 000 000 of bitcoins in infinite future.

Algorytm is like that: when network achieved 10 500 000 of coins reward was divided by 2 and was 25. Now we are waiting to mine half of the rest of the bitcoins to mine and then reward will be divided by 2 next time and will be 12.5. This way number of bitcoins in circulation will never hit 21 000 000.


text:
About blockchain.info Api Usage

When I got the code I use a url such as abc.com and I hope to know if I use my api in def.com will it work? If so what is the url meaning?
Every time it will generate wallet and if I use this API to receive bitcoin how will the coin go to my wallet?
When the API got bitcoin it will give me a response so my question is which should I use? There are 3 method for it.


text:
Bitcoin mixing and transaction sizes
I'm pretty clear on how a Bitcoin mixer obscures transaction history, but I don't understand how an observer is not able to reasonably link the source and destination wallets simply based on the transaction sizes.
Example,

I deposit 100 BTC into a mixing service's wallet
Over some time the mixing service places 100 BTC into another wallet
I have created.

If an observer has some interest in tracking me, they can view all wallet balances and determine which have had 100BTC placed into after my initial transfer to the mixing service. Assuming I don't use the end wallet for any other purposes, an observer simply needs to look for all wallets where about 100 BTC was deposited in them recently. This is probably a small list, and becomes even smaller as the amount to launder grows. If I wanted to launder 10000 BTC through a mixer, there are probably very few wallets that will have this amount deposited into them over such a short period.
The answer seems to be, "keep transactions small when mixing" but in a network where there is not much activity (compared to fiat currencies) it seems like tracking down laundering activity isn't very hard.

it seems like tracking down laundering activity isn't very hard

Well, ... maybe not too hard to find patterns to highlight where to look further, but probably hard to prove beyond a reasonable doubt.

That's not really a question. Anyway, you can supply multiple addresses to the mixing service and make sure the amount sent to each one is small enough to be intermingled with others. Addresses are cheap, and the service should have the option to upload them in bulk.

You cannot really determine which addresses are associated in one wallet unless several are linked when a transaction is funded, then you have a probability that they may be from the same wallet.

The mixing service could use various means to obfuscate the mixing - for example:

It can make you send coins to some off-line address, then send you your coins from its own supply of bitcoins before introducing your coins into the circulation again. This way it would appear that the transaction took place before you send the coins to the mixing service, and thus be harder to link
The service could split your Bitcoins into many smaller amounts and launder them each individually
It could deposit some of your money into some eWallets or similar services that use a shares pool of coins
It could use your money to purchase mining hardware and mint you fresh coins
The service could pay your money back to a few of your receiving addresses, making finding the final amount harder

Generally, there are many creative options of hiding things in the Bitcoin network, you just have to use your imagination.


text:
How do I buy Bitcoins safely face-to-face?
I've made a contact via LocalBitcoins.com and am going to buy some coins with cash. The seller is not verified, but as we will meet, it sounds ok:

I show him the cash.
He transfers the Bitcoins.
We wait one block.
I give him the cash.

Is this safe enough or is there anything I should take care of? Any scams known?
He requested to use my mobile internet, though (will enable Wi-Fi hotspot on the smartphone).

I guess that waiting a little longer is not possible, otherwise I would suggest doing so.

Shamelessly summarized from this extensive guide on local transactions:

You want to meet in a sufficiently public location, such as a pub or mall, preferably one that has an open wifi.
If you have agreed on terms in beforehand, print out what you agreed upon and take it with you.
If you have not agreed on terms yet, be sure to check the current price of bitcoin during the meeting.
Wait for the transaction to complete and check if the right amount was paid. If the other person is willing to wait around for one additional block together that is a good sign.
Specify your expectations in advance: When and where to meet, what each person will have on hand to make the deal, how the price for the bitcoins will be calculated.
Consider taking a second person along for additional safety.

LocalBitcoins.com features a transaction service which guarantees that bitcoins have arrived to your LocalBitcoins.com wallet.

You get a secret code when the bitcoin seller enables transaction service (escrow enabled) on the trade
When the bitcoin seller releases the transaction the seller gets SMS with the your secret code
Ask the seller and if he/she knows your secret code from his/her SMS it is safe to hand over the cash as you know bitcoins are then in your LocalBitcoins.com wallet
Now you can transfer bitcoins from LocalBitcoins.com wallet to any wallet you wish

https://localbitcoins.com/faq#howto_transaction
Sometimes when somebody has suggested a deal where there the payment is 50% now and 50% later, it is a sign of potential scam.

One more thing: Meet in a public place like a bar.

They have interesting services, yes. But I didn't set it up and it costs 1% fee actually, so the question was rather meant without escrow service.

My answer would be: "There is no way, to protect self from rapid scammer."
You are, probably, should spent a great time with seller, say 3, may be 4 hours.
E.g. See this thread: bitcointalk.org: If confirmation takes 10 minutes, how will I buy coffee at Starbucks?
Another way is to use an arbiter, e.g. www.bitrated.com

Bitcoin arbitration marketplace Protect yourself against online fraud
  with Bitcoin's m-of-n transactions.

Before you go to give your money to seller, an arbiter confirm transaction, wait for seller's confirmation, than send bitcoins to you.


text:
Instawire fees over Bitcoin Central fees and their respective KYC policies?
Instawire, Bitcoin-Central, Instawallet, Paytunia and Paymium are seem to be closely related, they cross reference each other on their sites, though their respective guarantees for their services are quite different (that was two links in two words just it's difficult to see it on your platform, perhaps you can fix that) which is interesting.
The question is why Instawire charges much more than the prices you can get on Bitcoin-Central? Maybe because the first one is a service and the latter one is an exchange. But perhaps do they have different KYC policies? Though I'm not sure about Instawire' KYC (Know oyur customer) policies they state on their site that you can send up to 100 euros, though, for a high fee. Maybe you pay for your privacy with this service? On the other hand, Bitcoin-Central requires your personal documents for even the smallest transactions, right? Though I'm not sure, didn't find these data explicitly on their sites.

You got the answer in the question : the fees are higher on Instawire because it is a service, not an exchange.
The fact is also that (until Bitcoin is legally considered a currency) sales of Bitcoins are subjected to European VAT which instantly adds 19.6% to the price. (If Paymium buys a Bitcoin at 10 EUR, it must sell it at 11.96 EUR to start breaking even).
There is no legal requirement to do KYC on Instawire as no funds are held on behalf of users, sometimes documents might be requested, but when they are it is for fraud-prevention purposes, not KYC. The 100€ limit is also a fraud-prevention measure.

Still, not quite sure about who would want to use Instawire and why? It does not add to privacy obviously as it uses a bank wire. Privacy conscious people would rather use Bitcoin-OTC, right? Yeah, that might have a learning  curve and it's not Insta.