text:
What will be happen if 21 million of bitcoins become the property of one?
Let's assume, that  the day already came, when emission of bitcoins completed, and we have the 21 millions of bitcoins. Let's say it happen that all these Bitcoins at one moment became the property of one person (for example because of the vulnerability of the system), which says that will not make any transaction and produces all kinds of steps to achieve this target(the deletion of the account or something else). So here is the question - what will be happen if 21 million of bitcoins become the property of one?

Related: Could bitcoin be destroyed if an entity cornered the market?

It's entirely up to the people living at this hypothetical future point.  There's no current rule about what happens.  Maybe when this happens, people are tired of Bitcoin, so they go back to trading seashells.  Or maybe when this happens, there's something better than Bitcoin available, so they all switch to that.  Or maybe they just restart Bitcoin and start mining again.
Remember that Bitcoin is a consensus system. Each user can change the software to do whatever he wants it to do.  If enough people all run the same software, and that software is designed to converge on a consensus block chain, all of those people will have the same block chain---even if it isn't the same block chain we use today.  Whatever rules we use today can be changed by people in the future (including our future selves), so there's no risk of ever permanently locking ourselves out of the block chain.

They would have no value.
As such this cannot happen. If less people have less bitcoins the value of btc goes down as the utility goes down, as such holders would likely dump the btc which makes them cheaper and would likely distribute them among others.
It's more likely though that btc loses value because a better from of decentralized money will replace it.


text:
Which exchanges allow me to transfer funds from my CurrencyFair account?
[Update: In July, 2013 CurrencyFair has stopped allowing delivery of funds to any Bitcoin exchanges.]
I can add funds to my CurrencyFair account via a bank transfer from a number of countries.  This will be a convenient method if I can then send those converted funds as a bank wire transfer to a Bitcoin exchange.
TransferWise used to allow me to do the same thing, but then stopped after their banking partners "weren't comfortable with Bitcoin".
Are there any exchanges which allow this?

Here's a good reddit post with comments on the subject: http://www.reddit.com/r/BitcoinUK/comments/1b8rug

Not all bank wire transfers contain the same information so this may vary based on which bank wire network is used.
For instance, CurrencyFair may function as a method to add funds from a UK account (GBP) using a bank wire and then after conversion to EUR make a withdraw as a SEPA wire transfer to BITSTAMP.net, or Mt. Gox, and any other exchange that accepts SEPA transfers.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
Future-proofing a deflationary currency from future counterfeiting
Say someone locks away a wallet in durable storage for 100 years and BitCoins are still actively used.
Are those BitCoins still going to be valid if they haven't been traded in/upgraded to the newer protocols?
I've seen other answers on this site that suggest either that 1) BitCoins will need to be upgraded by a certain block (at the switching of the hash function and protocol, for example, to adapt to any discovered weaknesses) OR 2) that they will forever be valid but that future equipment might be able to steal away those bitcoins (or even generate never-before-seen ones under the older protocols).
1) Would be awful, it seems to me.  What if you miss the deadline because you're in a coma and nobody knows to keep your wallet updated?
2) Seems like a danger for a deflationary currency where the older money is easier to counterfeit AND is worth more.
Perhaps I'm just confusing matters of BitCoin, Blocks, and Wallets?
As I understand it, if the first BitCoin ever made had been squirreled away and the currency takes off as a success, the novel and deflationary nature of the currency will make the exchange value of that first BitCoin very high compared to it's initial exchange value.
Over time, weaknesses in the original hash functions may be found and counterfeiting early BitCoin may become practical.  And the reward for doing so seems to me that it would be higher than counterfeiting BitCoin of the future-present!
In the physical world, finding a buried treasure of gold or a sack of US dollars has a lot of protections against counterfeiting.  I don't know how old of a design of US dollars banks would accept, but I guess that as long as you can do a convincing show of where you found it and forgery experts examine it all different ways and it checks out, they you're entitled to trade up.  Gold is pretty easy - can't fool people for too long.
Authenticity of BitCoin is all in the math, so if the technology to forge the math is practical at any point in the assumed infinite future of technological advancements then the forgery would be undetectable.
Due to inflation, an old $20 would get you a lot more than it did today.  But then again, I'm assuming that the old $20 and the new $20 are equivalent, once the old $20's authenticity is established.  And due to deflation, a BitCoin today will get you a lot less than the equivalent BitCoin in the future.
With inflation, the standard denomination of the future might be $100s or $1,000 or $10,000 ...  so a recovered or counterfeit old $20 isn't worth much, and a sack of $10,000 bills from 1960 would be hard to explain!
With deflation, the standard denominations get smaller, so a counterfeit old BitCoin would be easy to explain and forge.
So we could require that people keep their wallets updated.  You mean if I don't keep up with my BitCoin Updates every Tuesday that my bank accounts would be wiped clean?  But that seems unacceptable to me - seems that a powerful group could do a lot of damage to a person or a population by somehow disrupting or disallowing access to their wallets.  I don't know how that would play out, but it seems plausible that a scheme could be devised if money expires like that.

I see a valid question here, but the title should actually ask a question then act like a subject line on an email

I agree with @makerofthings7 -- rephrase your title as a question.

I don't get why you're talking about counterfeiting. The risk of theft is valid, but there isn't much anybody can do about that. Just pray that Sepc256k1 remains secure.

Well counterfeiting is like mining, except that it's shoehorning in of an old-style bitcoin into the historical chain of transactions.  It's the difference between painting a new masterpiece vs faking the discovery of a "previously unseen" Picaso.

I guess if the historical chain is re-signed with ever-modern security then counterfeiting the historical record won't be an option

There are a few things one needs to consider:

Bitcoin software is bound to change. It will be adapted to new systems, hardware, and so forth. Expecting a program from now to work 100 years from now is probably not going to happen.
Bitcoin protocol probably will change, but the change will be less drastic. For example, block size might get changed. If a protocol changes, it makes software that uses old protocol not able to properly communicate with the network.
The last part that needs to be addressed, is whether or not the way bitcoins are "stored" will change. At the moment, everything is handled using secp256k1 ECDSA algorithm. In order to spend bitcoins, one needs to sign a transaction with their private key. The exact specific of what such a transaction might look like is likely to change, but the algorithm itself is very unlikely to change unless some serious threat appears for Bitcoin. At the moment, quantum computers are a thing that might or might not brake that algorithm in the future. If that was to happen, the algorithm would be changed.

In order to be able to access one's bitcoins 100 years from now, one would need to get their hands on a piece of software from that time (pretty easy), that works with the protocol at that time (very easy), and the Bitcoin protocol must still accept ECDSA signatures or at least private keys (unknown).
Provided secp256k1 is still secure in the future, your coins will be yours to claim (unless someone adds an unlikely exception of "coins older than X years cannot be spent").

The present algorithm for public-key/private key cryptogrophy won't survive the invention of quantum computers. It will likely be deprcated in a few decades. If you don't update at that point people with quantum computer will be able to calculate your private key and spend your coins.

So everyone has to upgrade to an Intel Quantum at the same time or any late adopters have their savings stolen?

@uosa: We don't know whether there a possible encryption scheme by which you can do public-key/private key cryptogrophy with a regular PC that can't be broken by a quantum computer. Progress in mathematics is hard to forcast.

Shor's algorithm doesn't impact ECDSA which is why the NSA uses it. Quantum computers currently only impact DLP and RSA based public key systems. Unless there is new research that I'm not aware of

You always can spend bitcoins for which you own the private key. No matter upgrades, versions, protocol changes. If you have your private key then you can get / calculate / derive the then-current key to open your Bitcoin wallet.
May be things become obsolete, like floppy drives.
What's more important is that hash functions used now may be broken at some point of time. In this case, you will have only hours to react. Or, community may save you through some kind of counter measures.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Tick and price data

Possible Duplicate:
Where can I find a graph of Bitcoin value vs USD for over 60 days?
Where can I get raw data series of Bitcoin prices?

Where can I get historical price data for bitcoin?  I know the Apis will give me current data
, but what if I want the day's ticks for say 100 days ago?

Then again, on second thought I suspect you want data points in a convenient format, and not a chart ... so I'm sorry I voted to close. Here's a +1 for you.

There's also this question: Where can I get raw data series of Bitcoin prices?, which looks like a duplicate to me. @Cliff, do you agree?


text:
Bitcoind start at reboot but RPC calls wont work
I have a pine64 (aarch64)
I have set a pruned node.
My user name is pine, when I start the node using bitcoind -daemon I can use bitcoin-cli without problem and the RPC calls are OK.
I want to set in crontab the automatic start of the node if it is rebooted the pine64.
I set crontab as follows
pine@pine64:~$ crontab -e

# m h  dom mon dow   command

@reboot /usr/local/bin/bitcoind &

My bitcoin.conf is this:
pine@pine64:~$ cat .bitcoin/bitcoin.conf
##
## bitcoin.conf configuration file. Lines beginning with # are comments.
##

# Network-related settings:

# Run on the test network instead of the real bitcoin network.
#testnet=0

# Run a regression test network
#regtest=0

# Connect via a SOCKS5 proxy
#proxy=127.0.0.1:9050

# Bind to given address and always listen on it. Use [host]:port notation for IPv6
#bind=<addr>

# Bind to given address and whitelist peers connecting to it. Use [host]:port notation for IPv6
#whitebind=<addr>

##############################################################
##            Quick Primer on addnode vs connect            ##
##  Let's say for instance you use addnode=4.2.2.4          ##
##  addnode will connect you to and tell you about the      ##
##    nodes connected to 4.2.2.4.  In addition it will tell ##
##    the other nodes connected to it that you exist so     ##
##    they can connect to you.                              ##
##  connect will not do the above when you 'connect' to it. ##
##    It will *only* connect you to 4.2.2.4 and no one else.##
##                                                          ##
##  So if you're behind a firewall, or have other problems  ##
##  finding nodes, add some using 'addnode'.                ##
##                                                          ##
##  If you want to stay private, use 'connect' to only      ##
##  connect to "trusted" nodes.                             ##
##                                                          ##
##  If you run multiple nodes on a LAN, there's no need for ##
##  all of them to open lots of connections.  Instead       ##
##  'connect' them all to one node that is port forwarded   ##
##  and has lots of connections.                            ##
##       Thanks goes to [Noodle] on Freenode.               ##
##############################################################

# Use as many addnode= settings as you like to connect to specific peers
#addnode=69.164.218.197
#addnode=10.0.0.2:8333

# Alternatively use as many connect= settings as you like to connect ONLY to specific peers
#connect=69.164.218.197
#connect=10.0.0.1:8333

# Listening mode, enabled by default except when 'connect' is being used
#listen=1

# Maximum number of inbound+outbound connections.
#maxconnections=

#
# JSON-RPC options (for controlling a running Bitcoin/bitcoind process)
#

# server=1 tells Bitcoin-Qt and bitcoind to accept JSON-RPC commands
#server=0

# Bind to given address to listen for JSON-RPC connections. Use [host]:port notation for IPv6.
# This option can be specified multiple times (default: bind to all interfaces)
#rpcbind=<addr>

# If no rpcpassword is set, rpc cookie auth is sought. The default `-rpccookiefile` name
# is .cookie and found in the `-datadir` being used for bitcoind. This option is typically used
# when the server and client are run as the same user.
#
# If not, you must set rpcuser and rpcpassword to secure the JSON-RPC api. The first
# method(DEPRECATED) is to set this pair for the server and client:
#rpcuser=Ulysseys
#rpcpassword=YourSuperGreatPasswordNumber_DO_NOT_USE_THIS_OR_YOU_WILL_GET_ROBBED_385593
#
# The second method `rpcauth` can be added to server startup argument. It is set at initialization time
# using the output from the script in share/rpcuser/rpcuser.py after providing a username:
#
# ./share/rpcuser/rpcuser.py alice
# String to be appended to bitcoin.conf:
# rpcauth=alice:f7efda5c189b999524f151318c0c86$d5b51b3beffbc02b724e5d095828e0bc8b2456e9ac8757ae3211a5d9b16a22ae
# Your password:
# DONT_USE_THIS_YOU_WILL_GET_ROBBED_8ak1gI25KFTvjovL3gAM967mies3E=
#
# On client-side, you add the normal user/password pair to send commands:
#rpcuser=alice
#rpcpassword=DONT_USE_THIS_YOU_WILL_GET_ROBBED_8ak1gI25KFTvjovL3gAM967mies3E=
#
# You can even add multiple entries of these to the server conf file, and client can use any of them:
# rpcauth=bob:b2dd077cb54591a2f3139e69a897ac$4e71f08d48b4347cf8eff3815c0e25ae2e9a4340474079f55705f40574f4ec99

# How many seconds bitcoin will wait for a complete RPC HTTP request.
# after the HTTP connection is established.
#rpcclienttimeout=30

# By default, only RPC connections from localhost are allowed.
# Specify as many rpcallowip= settings as you like to allow connections from other hosts,
# either as a single IPv4/IPv6 or with a subnet specification.

# NOTE: opening up the RPC port to hosts outside your local trusted network is NOT RECOMMENDED,
# because the rpcpassword is transmitted over the network unencrypted.

# server=1 tells Bitcoin-Qt to accept JSON-RPC commands.
# it is also read by bitcoind to determine if RPC should be enabled
#rpcallowip=10.1.1.34/255.255.255.0
#rpcallowip=1.2.3.4/24
#rpcallowip=2001:db8:85a3:0:0:8a2e:370:7334/96

# Listen for RPC connections on this TCP port:
#rpcport=8332

# You can use Bitcoin or bitcoind to send commands to Bitcoin/bitcoind
# running on another host using this option:
#rpcconnect=127.0.0.1

# Create transactions that have enough fees so they are likely to begin confirmation within n blocks (default: 6).
# This setting is over-ridden by the -paytxfee option.
#txconfirmtarget=n

# Miscellaneous options

# Pre-generate this many public/private key pairs, so wallet backups will be valid for
# both prior transactions and several dozen future transactions.
#keypool=100

# Pay an optional transaction fee every time you send bitcoins.  Transactions with fees
# are more likely than free transactions to be included in generated blocks, so may
# be validated sooner.
#paytxfee=0.00

# Enable pruning to reduce storage requirements by deleting old blocks.
# This mode is incompatible with -txindex and -rescan.
# 0 = default (no pruning).
# 1 = allows manual pruning via RPC.
# >=550 = target to stay under in MiB.
prune=1000

# User interface options

# Start Bitcoin minimized
#min=1

# Minimize to the system tray
#minimizetotray=1

Now, when the pine64 get rebooted the node starts but the RPC calls are not working, I get this error:
pine@pine64:~$ bitcoin-cli getconnectioncount
error: couldn't connect to server: unknown (code -1)
(make sure server is running and you are connecting to the correct RPC port)

EDIT: I have checked with top and both are under the same user "pine". The one started with crontab after reboot and the one I started using bitcoind -daemon

ps results when bitcoin -daemon is executed from cli

pine@pine64:~$ ps aux | grep bitcoind
pine      2214  9.9 22.6 1862152 461952 ?      Ssl  Oct31  95:02 bitcoind -daemon
pine     26429  0.0  0.0 121620   908 pts/0    S+   11:53   0:00 grep --color=auto bitcoind

ps results when bitcoin is executed after reboot in crontab

pine@pine64:~$ ps aux | grep bitcoind
pine       636 65.8 11.3 841216 230304 ?       DLl  11:56   0:11 /usr/local/bin/bitcoind
pine      1073  0.0  0.0 121620   904 pts/0    S+   11:57   0:00 grep --color=auto bitcoind

What am I missing in crontab?
Do I need to set RPC username and password? I rather not.
Thanks

I cannot provide the exact answer, but normally you say you have the user "pine", and everything works. When starting from your crontab, not. I guess the daemon should have the same "home dir" and user rights as "pine", which is not covered in your crontab. Look at the process, who is the owner of the bitcoin daemon, when running from crontab, and when running under "pine"... if you found it, you may want to put your answer below.

Hi @pebwindkraft I have checked with top and both are under the same user "pine". The one started with crontab after reboot and the one I started using bitcoind -daemon

hmm, so the process is running. Do a netstat -an to see if a process is listening on port 8333. And something which comes to my mind: maybe a cd to pine's home dir before, and see that PATH variables are the same. Or vice versa: use the pine user, and cd into /tmp, start bitcoind -daemon, and see if it works.

I think I've found the problem but I need your help to confirm my doubt.
First of all, I have check netstat and found 8333 currently is on listening mode.
Then I have checked PATH using printenv
PATH=/home/pine/bin:/home/pine/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games is the result
There is not a folder /home/pine/bin so I did a ls -la /usr/local/bin/ and got -rwxr-xr-x  1 root root  2615992 Oct 28 21:54 bitcoin-cli
So , does that means when bitcoind after a reboot is being executed by user root?

no, it is not executed as root, the listing ("ls -l") just says, it belongs to root, and anyone can execute it (the "x" in -rwxr-xr-x). It would still run as user "pine", as you confirmed in your 1st comment (when checking with top). btw: "ps aux" is probably the better way to do it. From what you posted, the bitcoin.conf file is in /home/pine/.bitcoin. Folder /home/pine/bin is not required, cause executable is in /usr/local/bin. Can you do a pwd (print working directory) in front of the crontab call? If this doesn't help I need to re-activate my Raspberry. It has SuSE, but should be the same.

omg current pwd is /tmp
seems somthing's wrong. can you explain how to do it in front of the crontab call?

just checked on my RasPI2, and it works with SuSE armv7 Linux 4.1.19-1-rpi2. I gave it the "@reboot bitcoind -daemon" command in the crontab for the user normally running bitcoind. I can execute bitcoin-cli without problems (e.g. "bitcoin-cli stop"). You are running arch linux?

I just found went through my system, and stepped over the config item in bitcoin.conf: if you put server=1 in the bitcoin.conf, then maybe you do not need to create rpcuser and rpcpassword...


text:
Manually banning nodes through CLI
I cant find this info: How can I ban through CLI a peer connected to my full node?
I like how can I do it in the 0.12.0 GUI just with right-click and choosing for how much time I want to ban the peer.
tia

As correctly answered here https://bitcointalk.org/index.php?topic=1390192.msg14122567#msg14122567
setban "ip(/netmask)" "add|remove" (bantime) (absolute)

Attempts add or remove a IP/Subnet from the banned list.

Arguments:
1. "ip(/netmask)" (string, required) The IP/Subnet (see getpeerinfo for nodes ip) with a optional netmask (default is /32 = single ip)
2. "command"      (string, required) 'add' to add a IP/Subnet to the list, 'remove' to remove a IP/Subnet from the list
3. "bantime"      (numeric, optional) time in seconds how long (or until when if [absolute] is set) the ip is banned (0 or empty means using the default time of 24h which can also be overwritten by the -bantime startup argument)
4. "absolute"     (boolean, optional) If set, the bantime must be a absolute timestamp in seconds since epoch (Jan 1 1970 GMT)

Examples:
> bitcoin-cli setban "192.168.0.6" "add" 86400
> bitcoin-cli setban "192.168.0.0/24" "add"
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "setban", "params": ["192.168.0.6", "add" 86400] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/


text:
Efficient way to migrate a pruned node
I would like to know what are the step to succefully migrate a pruned node.
I have a Raspnode (rPi2B+) and it is so slow that it doesnt seem to sync the blockchain after several days...
I want to sync the node that I have in my laptop and move it (pruned) to the Raspnode.
I have copy and paste all the files in the .bitcoin folder and when I execute the bitcoind -daemon command the follow is in the debug.log file
2016-03-22 23:25:55 Opening LevelDB in /home/pi/bitcoinData/blocks/index
2016-03-22 23:25:59 Opened LevelDB successfully
2016-03-22 23:25:59 Opening LevelDB in /home/pi/bitcoinData/chainstate
2016-03-22 23:25:59 Opened LevelDB successfully
2016-03-22 23:26:37 LoadBlockIndexDB: last block file = 474
2016-03-22 23:26:45 LoadBlockIndexDB: last block file info: CBlockFileInfo(blocks=57, size=47829393, heights=403730...403810, time=2016-03-22..$
2016-03-22 23:26:48 Checking all blk files are present...
2016-03-22 23:26:48 LoadBlockIndexDB(): Block files have previously been pruned
2016-03-22 23:26:48 LoadBlockIndexDB: transaction index disabled
2016-03-22 23:26:49 LoadBlockIndexDB: hashBestChain=000000000000000005323717f768df54444ee6dfccbe080548287f120546e6e3 height=403810 date=2016-03$
2016-03-22 23:26:49 init message: Verifying blocks...
2016-03-22 23:26:49 Verifying last 288 blocks at level 3
2016-03-22 23:26:51 LevelDB read failure: Corruption: not an sstable (bad magic number)
2016-03-22 23:27:14 Corruption: not an sstable (bad magic number)
2016-03-22 23:27:14 : Error opening block database.

Do you want to rebuild the block database now?
2016-03-22 23:27:14 Aborted block database rebuild. Exiting.
2016-03-22 23:27:14 Shutdown: In progress...
2016-03-22 23:27:14 scheduler thread interrupt
2016-03-22 23:27:14 StopNode()
2016-03-22 23:27:14 Shutdown: done
2016-03-22 23:39:01 AppInit2 : parameter interaction: -prune -> setting -disablewallet=1
2016-03-22 23:39:05 Prune configured to target 30000MiB on disk for block and undo files.
2016-03-22 23:39:08

The idea is to sync the node in my laptop and then maintain the syncing (and pruning) on the rapsberry pi because I cant run the node all the time in my laptop.

Copying .bitcoin folder should work. Make sure bitcoind is not running (try ps -ef | grep bitcoin)  before you attempt to copy. Also make sure bitcoin.conf is same in both places
Also, change the bitcoin.conf file with the new datadir , rpcuser and rpcpassword

Is it safe to share pruned data? If I just want to sync a 500M pruned node can I download the pruned data from a node with the same configuration? In order to get a new node synced ASAP.

@pinhead it should work but I am not sure, if you have done it and it works please update it here. Thanks


text:
help my Bitcoin core wallet won't sync
more  Bitcoin core won't synchronize with network but my wallet has a balance of 0.00  it I have done transactions that reply back as true and if I do balance for those addresses it shows transactions  current in the console then I look around main wallet and still 0

how is your internet connection? what is your OS?

What Bitcoin Core version? What does getchaintips in the console report?


text:
Where are my bitcoins - unconfirmed transactions
Using Bitcoin Core wallet, I sent coins to an address of mine outside of the wallet. All three transactions sit as unconfirmed though show in blockchain.
https://blockchain.info/address/1HYK6Key5EUwAyaxh6SniXKEjSMsPAgY94
they are the bottom three transactions. Not sure why they are showing as "spent" - I did send about 0.65btc to this wallet after which I then spent.
So in short - the bottom three transactions are showing as unconfirmed on BitcoinCore, the btc is not in the account they were sent to. Where are they?
Further info - the bottom 2 of the 3 transactions were sent almost a week ago though didn't show up in blockchain until I reinstalled the wallet app. However, BTW is still nowhere to be found. Fees - bottom two were sent minimum, top of the 3 was sent as recommended and all are showing as "0/unconfirmed" in the wallet app

the precise transation IDs are: d3f86df12c12801ca97244a773287226fd1e833e7151b1ab3a90bff930351e50-000     ---   2c1f5f44d33505eeb2780866626745511e293f60aa8a79c9ef507dfc6317f096-000    -----  90f701b16cc7fd3c463f82f2ec70b80b6a361f18833087bc0731d045787d8fdc-000

Does no one know what the issue is? Seems a bit basic that when I send coins from wallet A to wallet B they ought to arrive...

The transaction d3f86df12c12801ca97244a773287226fd1e833e7151b1ab3a90bff930351e50 has a zero fee, so I doubt it will be confirmed anytime soon. Do you know how to double spend it and specify a higher fee?
The other two transactions also have a very low transaction fee but that would still be OK. The problem is that they are spending from the zero fee transaction. Therefore they cannot become confirmed before the parent with zero fee is confirmed.
You say that you sent those transaction a week ago, but Blockchain shows that it received them yesterday. Maybe they were dropped from the mempool after some days last week and now your wallet did just rebroadcast them. What wallet do you use?

thanks , this has now been confirmed. I sent the btc literally 10 days, straight after I sent another which went through fine. The zero fee transaction basically sat there and did nothing and hadn't registered for a week and half on blockchain. I reinstalled the wallet software, using an older backup of the wallet before this transaction(just reinstalling with doing a bitcoin synch using the current wallet STILL did not send the transaction through!) Once I did a fresh install, using an old wallet, the wallet software finally sent the zero cost transaction and everything else then processed.

In short, there is clearly an issue with Bitcoin Core. I sent a transaction to this precise address which went through fine, then two hours later I sent another transaction with zero fee (which I always do!) and that transaction did not at all register on blockchain. Had to do the above to get it to register. Seems like a fairly serious failure - and since it would not register using the wallet saved after I sent it and required an old wallet before these transactions to register on blockchain it's a bit of a serious error

I would advise against sending any transaction with zero fee. There is no longer any incentive for a miner to include a zero fee transaction and with the standard settings those zero fee transactions will not even be propagated through the network.


text:
listtransactions returning duplicate transactions with category "Send" & "Received" both
I am facing serious problem in listtransactions call. I am getting duplicate transactions with "send" and "Received" category. For I have sent some bitcoins from 31zeoskE8zeyQARFEVzwJzsp7GQpLn5zhF to 13MwqVWaNjad4xbGV5WQPaPVcMekU5YJmB. And when I call listtransactions, I get this output,
    {
    "involvesWatchonly" : true,
    "account" : "",
    "address" : "3Ft9W7HfXeBMwuwcfehV9UPs5gnxbc7Wji",
    "category" : "receive",
    "amount" : 0.00019000,
    "vout" : 1,
    "confirmations" : 20,
    "blockhash" : "0000000000000000007f43360b2d7005c8f25013647359d468b8c2ef281672ab",
    "blockindex" : 438,
    "blocktime" : 1437928178,
    "txid" : "eb0f12741947a3be8fdbb15c0401a663e45bd0c68b317b58f250fbb3a698e5fa",
    "walletconflicts" : [
    ],
    "time" : 1437928101,
    "timereceived" : 1437928101
},
{
    "involvesWatchonly" : true,
    "account" : "",
    "address" : "31zeoskE8zeyQARFEVzwJzsp7GQpLn5zhF",
    "category" : "receive",
    "amount" : 0.00010000,
    "vout" : 0,
    "confirmations" : 20,
    "blockhash" : "0000000000000000007f43360b2d7005c8f25013647359d468b8c2ef281672ab",
    "blockindex" : 438,
    "blocktime" : 1437928178,
    "txid" : "eb0f12741947a3be8fdbb15c0401a663e45bd0c68b317b58f250fbb3a698e5fa",
    "walletconflicts" : [
    ],
    "time" : 1437928101,
    "timereceived" : 1437928101
},
{
    "involvesWatchonly" : true,
    "account" : "",
    "address" : "3Ft9W7HfXeBMwuwcfehV9UPs5gnxbc7Wji",
    "category" : "send",
    "amount" : -0.00019000,
    "vout" : 1,
    "fee" : -0.00010000,
    "confirmations" : 20,
    "blockhash" : "0000000000000000007f43360b2d7005c8f25013647359d468b8c2ef281672ab",
    "blockindex" : 438,
    "blocktime" : 1437928178,
    "txid" : "eb0f12741947a3be8fdbb15c0401a663e45bd0c68b317b58f250fbb3a698e5fa",
    "walletconflicts" : [
    ],
    "time" : 1437928101,
    "timereceived" : 1437928101
},
{
    "involvesWatchonly" : true,
    "account" : "",
    "address" : "31zeoskE8zeyQARFEVzwJzsp7GQpLn5zhF",
    "category" : "send",
    "amount" : -0.00010000,
    "vout" : 0,
    "fee" : -0.00010000,
    "confirmations" : 20,
    "blockhash" : "0000000000000000007f43360b2d7005c8f25013647359d468b8c2ef281672ab",
    "blockindex" : 438,
    "blocktime" : 1437928178,
    "txid" : "eb0f12741947a3be8fdbb15c0401a663e45bd0c68b317b58f250fbb3a698e5fa",
    "walletconflicts" : [
    ],
    "time" : 1437928101,
    "timereceived" : 1437928101
}

Why I am getting duplicate transactions in this output! ?
Any Help will be appreciated, Thanks

It shows up as both send and receive because you sent Bitcoins from the address to the same address. The transaction sends and receives to the same address.

No @NickODell, I have sent from 31zeoskE8zeyQARFEVzwJzsp7GQpLn5zhF to 13MwqVWaNjad4xbGV5WQPaPVcMekU5YJmB

And you've also sent to 31zeosk[snip]. Check the link in my last comment.

Ok that makes sense!
Now what about this, I have edited my Question, You can check another example! in my edited question @NickODell

Same thing. https://blockchain.info/tx/eb0f12741947a3be8fdbb15c0401a663e45bd0c68b317b58f250fbb3a698e5fa It withdraws from 3Ft9[snip] and deposits into 3Ft9[snip].

Yup but why "send" & "received" for 31zeoskE8zeyQARFEVzwJzsp7GQpLn5zhF ??? @NickODell

@NickODell I will be very thankful to you if you just reply to my last comment. Thanks in advance!

One is showing your send, the other is showing your receipt.  Without seeing both entries your accounting would not add up!

Unquestionably, you will see these transactions.
if you have 10 inputs and you are about sending a transaction you should see 11 transactions.
and if you are not sending the full amount and there's some change you should see one "receive transaction" while sending and it's for change.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
What does this blockchain.info error mean?
I added bitcoin payment to my website with bitcoin daemon, but one user is having an error with the blockchain.info API:

Warning! this bitcoin address contains transactions which may be double spends. You should be extremely careful when trusting any transactions to or from this address.

https://blockchain.info/address/163cTKxPehxPi4nJ3oTHAso6eXWywfYr7N
Should I confirm this user's withdrawal, or should I block them? And what is significance of this error? If I use bitcoind to count confirmations, it's not dangerous to accept funds from such an address, right?? Thanks!

Do you have a service which accepts deposits and withdrawals? Can you give an url? Do you know the address 1PN9vEwey7iikTHoKvrrUGJY7PtymhyNNV? Is it the deposit address of your service?

Why do you use both the bitcoind daemon and blockchain.info API?


text:
If bitcoin fails as a currency, how will blockchain tech still be secure for other applications?
We often hear proponents, like Andreas Antonopoulos, say things along the lines of Bitcoin being an application of the Blockchain technology and that Bitcoin as a currency can fail, but blockchain technology will continue.
But the blockchain is only secure (and therefore useful) if there is a large enough and diverse enough (e.g. no one with >50% of the mining power) network of miners securing the network.
If the USD to BTC value goes down too low, or Bitcoin as a currency (for whatever reason) fails, the miners will stop mining. Is it therefore possible that this could then make the bitcoin blockchain technology insecure and put the other applications built on top of the blockchain technology at risk?
I guess one might say, what Andreas means is that new blockchain mining networks, independent of bitcoin could be setup. But what makes the bitcoin blockchain so good, is because the network of miners is so large (and therefore so secure), is it not?

There are a few examples of how alternative, non-currency, applications of blockchains are secured. In most cases, it involves formally requiring some sort of a new blockchain token to use the service that the alternative blockchain provides.

Namecoin is the prime example that comes to mind. Namecoin was the first ever fork of Bitcoin to make an altcoin. It uses its own token (namecoins) to register domain names. Thus, the mining is incentivized through a token which provides access to the service that the block chain provides. This model could be applied to other applications.
You may also find Counterparty to be an interesting example. They have their own token (XCP) that limits access to the creation of new tokens. From what I have read, however, they use transactions on the bitcoin block chain for security and use XCP for spam prevention. This is an interesting case because it shows how the bitcoin blockchain can be used for something other than just the transferring of bitcoins.

It all comes down to there being a use-case for your blockchain. Bitcoin is mainly advertised as a new currency, so if it no longer is valued as a currency, then the chain will likely become insecure.

I had heard about namecoin before but assumed it used the bitcoin blockchain too. Good to know this is false. I'm still having a hard time understanding how namecoin as a domain registrar works though.. another Q for SE I guess. Thanks for the answer and edit, marking as accepted.

I understand it exactly the same way as you .. the currency needs to be worth the time and effort of the miners or at least the have to believe it is in the long run.

Thanks. Glad I'm not the only one concerned.

He means that the use case of currency may bot be successful and other alt could get it right  Or be more advanced and replace bitcoin but that blockchain technology cannot be uninvented.
PD, Namecoin uses another blockchain that is mined at the same time with bitcoin. Only BTC miners can get NMC. Why not 100% of them do it is another story.

What do you mean by PD?


text:
Where can I find the structure and layout of what exactly gets hashed by miners?
I understand that a miner has a list of bitcoin transactions since the last time a a block was discovered. The first entry is the reward for who discovered the previous block. As more transactions gets added, they're appended to this list. This part is speculation, but I think there's also a nonce that the miners inject in order to produce a hash output that meets the difficulty.
Where can I find out the specifics about what exactly is hashed? I'm looking to understand the exact bytes and structure.

possible duplicate of What are bitcoin miners really solving?

The first entry is not the reward for who discovered the previous block. The first transaction is unique to each miner and causes the block reward of the upcoming block to be spend to the miner that discovers the block.

The data that's hashed is the block header. You can find a description of the format and layout at https://en.bitcoin.it/wiki/Block_hashing_algorithm

How does a Generation block differ? What goes in the hashPrevBlock section of the generation block? All zeros?

@CoreyOgburn: Do you mean the genesis block, the very first block in the block chain?  Yes, the hashPrevBlock field is set to zero.  Everything else is the same.


text:
Does a transaction with a lock time need more time to be confirmed?
I've made this transaction in the testnet:
https://testnet.blockexplorer.com/tx/2f18c646a2b2ee8ee1f295bb5a0f5cc51c5e820a123a14b0c0e170f9777518bb
It's a multisign tx with locktime. The locktime has expired and the tx is signed, but it isn't confirmed... Does somebody know why this tx isn't confirmed?
Thanks

You may need to send it again? Nodes don't keep timelocked transactions in their mempool. It's the responsibility of the sender to make sure the transactions is stored until the locktime expires and then to broadcast the transacion. Another reason might be a too low fee, but I haven't clicked your link, so I'm just guessing.

Finally, the tx is confimed (almost a day to confirm). It's a lot of time. The fee was 0.00010001 BTC. I've tried to send another transaction with a lock time and 0.00033 fee but this isn't confirmed to past an hour. Does a tx with lock time need more time to be confirmed?

Again: did you re-send the transaction after the lock time expired?

Mempools are constantly changing. Each node has its own policy (how much of it to keep, when it gets cleared, which ones stay when a block is found, etc) so it's difficult to know if your transaction is on the network. Generally, you can be sure that a tx with a sufficiently high locktime won't be in the blocks before that locktime, but you are not guaranteed that it will be in the blocks after for a lot of other reasons (insufficient fee and mempool turnover being the two big ones). Generally with these types of transactions, it's recommended that you broadcast after the locktime has passed.


text:
Import private key on multiple computers
I decided to make some custom addresses for personal use and I have two computers running bitcoin clients. I imported the private key of the wallet I generated to the wrong computer and then I imported it to the correct computer. So now I have two wallets with the same public address in them. Questions are:

What happens when I receive a payment?
Will it take itself out of either wallet?
Is there anything I can do to fix this?
Thanks

Incoming payments will show up in both wallets.
If you spend any of the balance, the other wallet may show a 0 balance because the "change" will only go to the wallet you sent from. The other wallet won't know about the new "change" address.
The safest thing to do is to transfer all the funds to a new address.


text:
Why is the accept / utility of one of my miners consistently higher than the others?
I'm playing around with a couple of Antminer U2s, and two Block Erupters, running them off of a vanilla BFG setup using BTCGuild, I'm consistently seeing the following:

So, I'm curious as to why one of my miners (always a single AMU) always has such a higher Accept and Utility statistic than the other devices.

It appears that the worker with the more shares/utility is solving low difficulty pool shares, where the other 3 are probably mining at a more appropriate difficulty level.
Utility is the measure of how many shares are submitted per minute (diff1*pool difficulty mining at). That suggests further that the unit is working on lower difficulty shares than the other workers.
Usually on your pool website there will be a spot to change worker difficulty, and for those units, I would recommend 2 for the ICA and 8 for AMU, but you could always adjust according to your preference.


text:
Xemian Xchange Api for Java, returning a default of 100 market orders
For sometime I am using this java API http://xeiam.com/xchange/ for building bitcoin trading robots. Today I got a bit stuck and I wanted to see if somebody had the same issue before.
I call the order books like this:
OrderBook orderBook = exchangeMarket.getExchange().getPollingMarketDataService().
                                getOrderBook(CurrencyPair.LTC_BTC, new int[] {20});

My problem is that the orderBook object contains 100 asks and 100 bids. I just want 20. Does anybody know why this is not returning the amount I pass in the second parameter? BTW, if I try 150, it also returns 100. I don't know how to modify the amount of returned elements.

The xchange docs say that the meaning of getOrderBook's second argument is exchange-specific. Does the exchange you're polling support limits? Do they support them in the manner that you're using them?

@Nick ODell I am interested in the exchanges Cryptsy and BTCE, but I am not sure how to find if they support limits. Also if they do support, how do I pass the parameter? I tried different things like new Integer[]{20,20}... but nothing worked, I would like to confirm that indeed there is no such support in those exchanges.

The Cryptsy driver does not support this, or any kind of argument, actually.
https://github.com/timmolter/XChange/blob/df9eb4e4d95c5bb3954b1527f585d9238514fa94/xchange-cryptsy/src/main/java/com/xeiam/xchange/cryptsy/service/polling/CryptsyPublicMarketDataService.java#L39
Neither does BTCE.
https://github.com/timmolter/XChange/blob/df9eb4e4d95c5bb3954b1527f585d9238514fa94/xchange-btce/src/main/java/com/xeiam/xchange/btce/v2/service/polling/BTCEMarketDataService.java#L55
However, the BTCE getTrades method does support a limit argument.
https://github.com/timmolter/XChange/blob/df9eb4e4d95c5bb3954b1527f585d9238514fa94/xchange-btce/src/main/java/com/xeiam/xchange/btce/v2/service/polling/BTCEMarketDataService.java#L78


text:
Can I replace the fans in a Zeus Hurricane x3?
This thing sounds like there is a jet waiting to take off in my office.
Can I replace the fans with quieter ones? If so, can you recommend which fans to buy to replace the stock ones?
Thanks!!

Just looked up a video of this on youtube. Wow, that is loud. https://www.youtube.com/watch?v=zZ5j7MXGk3s

Maybe that's why they call it "Hurricane".

You're looking for a 120mm x 120mm x 38mm fan which can produce at least 120 CFM of airflow and runs on DC 12V. (Source.)
According to a random guy on the internet, the stock fans produce about 60-70dB of noise.
There are various fans you can buy, but they're all pretty similar in terms of noise.

http://www.newegg.com/Product/Product.aspx?Item=N82E16835213006

You can also buy one that has less airflow, but is much quieter.

http://www.newegg.com/Product/Product.aspx?Item=N82E16835132022

...or, if you've ever looked at your Hurricane and decided you wanted twice as much airflow, you could install this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16835706015
(The product reviews even use the phrase "jet engine.")

This will void your warranty. (Assuming you have one.)

Thanks. I guess I'm going to have to figure out how to move it to the garage. Im not sure I like living on an airport runway. Haha

Heres what you need:

TWO (yes two) equivalent size silent fans (these will do)
a CPU fan splitter cable (this is good)
Screwdriver (duh)

Extra points (Optional):

Drill with metal drill bit
Zipties

The Fractal Design Silent Series R2 have a noise rating of 18dB and push 66CFM of air.There are cheaper ones as well that push less CFM. Just to be safe I wouldn't cheap out on these, the more CFM the better. NCIX has awesome selection of fans and are always having sales so you might find something even cheaper.
Keep in mind that stock 120 CFM fan will not be operating at max capacity and a push-pull setup like what I am describing will operate at a much higher efficiency rating.
Heres what you wanna do:

Open up the case
Replace the front vent fan with one of the new silent fans taking care to orient the fan backwards so the air is pulled out of the machine (use zipties or rubber grommets to reduce vibration)
If you don't have a drill, jam one in between the radiator blades and the case on the other side, taking care to orient the fan so it is pushing air inside the machine. You can use a piece of rubber/metal/wood (I wouldn't recommend using something plastic)
Attach both fans together using the splitter cable, then plug the splitter cable into the mainboard or powersupply.
Reattach case

Extra Points:

With your Drill, and the case OFF drill 4 holes in the intake side equivalent to the 4 holes on the corner of the fan (try to line it up so the 4 holes are in the center of the radiator fan)
Line up the fan with the 4 holes and using zip ties, tighten the fan into place taking care to orient the fan properly

*Pro tip: loop the zipties from the fan-side so that the plastic nubs don't stick out and cut the tails off your zip ties for christs sakes!
Voila! you have reduced your 70-90dB monster growl to a 20-25dB kitty purr.
Air is pushed into and along the radiator blades by a 66CFM fan and is pulled along and out the other side by another 66CFM fan. Operating temps might be a little higher but nothing to worry about. Also can be used to quietly heat a room (save on heating in the winter).


text:
How do I create a new genesis block for an altcoin?
I'm trying to clone the Blackcoin sourcecode just for the hell of it but I can't seem to generate a genesis block. I can do it on normal coins, but not here. The Blackcoin developers seem to have shifted a lot of code into weird places.
For example, all of the coins major parameters are in chainparams.cpp. However, there is no code in the link above or in main.cpp to create a genesis block.
How do I make a genesis block for this coin?

I'd love to know myself but without being versed in C++ it's very difficult I gather. The other issue is the information is not shared openly in my experience. Why? Because of the influx of scams (Altcoin clones were released at the rate of 4-5 daily in July 2014; many were outright scams, including DafuqCoin, which was a Trojan, USBcoin, and Cachecoin, which just saw the developers charged) then there's the algorithms; Keep in mind Blackcoin is proof of stake and IIRC doesn't use sha256. I wish I could add more.

I am stuck here too. Have you find solution? Thx.

They just removed the gen-generation part from the sources as it's not needed after the genesis being generated and already implemented (hardcoded) into the sources.

Hi. Then where is working code for newest source?


text:
I transferred BTC from mtgox and they have disappeared - What should/can I do?
I sent 3 btc from mtgox to cavirtex. The address used is correct and I was given a transaciton ID by mtgox. Yet blockchain.info shows no record of a transaction and 3 btc are missing.
I have written to both mtgox and cavirtex to ask about them - still no replies.
What can I do? How do I know if they have been stolen?
This question with an accepted answer is related - or more to the point mine is a duplicate of it:
Transaction not found

Why would you write to cavirtex? To ask them why they didn't credit you for a transaction that has no confirmations?

Because they might know what I can do/try.

Check if the transaction is in the list of unconfirmed transctions. If it's not, then the sender is at fault, Mt Gox in your case. If it is, then just be patient. It can take awhile for a transaction to get included by a miner.

Thanks - the transaction is not in the list of unconfirmed transactions. What should I tell MtGox? What is the most likely reason for this happening?

@val You should tell Gox that they haven't performed your withdrawal and they need to do so. It's hard to know why it's happening without knowing about Gox's internal procedures. Since you have the transaction ID, they must already know what funds they're going to use, so it's hard to imagine why they wouldn't have released the transaction. (I have a theory though. If I'm right, when the withdrawals does happen, it will not have the transaction ID you were given.)

Thanks again. I'll do that. They have been deducted from the balance at Mt Gox. nether space...

Maybe the transaction id is just an internal transaction id and not a bitcoin transacion id. I have reviewed my withdrawals and in the accoun history you can see the address and in the emails there is a code but it is not a bitcoin transaction id.

@frisco Ahh, then they probably just haven't processed it yet.

@frisco Yes I noticed this code vs transaction ID difference you speak of too. (wow - awkward wording)


text:
What is the conversion then for MH/s to GH/s and so on
I've seen this answer and maybe I'm just tired

What is the difference between kH/s, MH/s, and GH/s?

1 kH/s is 1,000 hashes per second (sometimes mistakenly written KH/s).
1 MH/s is 1,000,000 hashes per second.
1 GH/s is 1,000,000,000 hashes per second.
1 TH/s is 1,000,000,000,000 hashes per second.

so if I have 1 TH/s I would have
1000 GH/s?

and 1 GH/s would be
1000 MH/s

or am I missing the math here?


text:
What does change address mean inside Electrum wallet?
I am bit confused with the change label that is inside Electrum Wallet . Can I receive bitcoin if i give this address which are under change label? What is the difference between Receiving and Change Label Address?

Start by reading http://bitcoin.stackexchange.com/questions/736/how-does-change-work-in-a-bitcoin-transaction

Receiving addresses are addresses generated specifically for sharing with people to send payments to you. Change addresses are generated by your wallet automatically when you send funds to someone else.
To understand how change addresses work, consider this example. Say you received 0.1 BTC once, and 0.2 BTC another time. Now you have two UTXOs (unspent transaction outputs) to use to send to someone else. Now you want to send 0.25 BTC to someone. You have to use both of your outputs to have enough to send, but then you have 0.05 too much. You can't partially spend UTXOs, so what you have to do is make a transaction that spends both the 0.1 BTC UTXO and the 0.2 BTC UTXO, and sends 0.25 to the receiver and 0.05 back to yourself in a new address called the 'change' address.
You should not be giving addresses from the 'change' section out to other people. Use receiving addresses for receiving, and let your wallet program automatically handle change addresses.

What will happen when you turn off change addresses in electric settings ?

"you should" means that technically I could, the btc would not become unusable and the app would pick it up, right? Now, what does the "Use multiple change addresses" mean?


text:
Does hardware specialization provide security against 51% attack via on-demand computing?
I've heard it argued that when a mining algorithm is prone to hardware specialization, the centralization that introduces (e.g. one factory producing 25% of all ASICs) is a security risk.
I'm wondering if there's also a security benefit to hardware specialization: Since the amount of on-demand computation available to purchase may vastly exceed the amount of computation going into mining a cryptocurrency, is there a risk of someone executing a 51% attack by briefly renting an amount of computation greater than the network's?
If that's a significant risk, does hardware specialization mitigate it by increasing the miners' computing power relative to the power of general-purpose on-demand computing?

Does hardware specialization provide security against 51% attack via on-demand computing?

It depends on what hardware the on-demand computing is offering. Hardware specialization might make a cryptocurrency less vulnerable to attack from inefficient on-demand hardware, like a botnet. But as hardware becomes more specialized, the on-demand hardware leasors tends to upgrade their hardware to stay competitive.
Keep in mind that the effectiveness of one's mining is relative to the total hash power of the network. If everyone on the network doubles their hashing power, everyone will continue earning the same # of coins after the difficulty adjusts.


text:
Are there any publications about deanonymizing Bitcoin?
At the Model United Conference I attend, there is a resolution proposed to de-anonymize BTC in order to cull Darknet transactions.
I know it is impossible but how do i prove it to the other delegates?
Scientific peer-reviewed publications would be amazing.

A good resource is http://arxiv.org/. Search bitcoin in the search bar, and then look for "anon" on the page to find articles about anonymization and de-anonymization in bitcoin.
Doing that, I found these examples:

http://arxiv.org/pdf/1510.07782.pdf
http://arxiv.org/pdf/1509.06160.pdf
http://arxiv.org/pdf/1405.7418.pdf
http://arxiv.org/pdf/1107.4524.pdf

authors: Костя Олимид

authors: Максим Коробкин


text:
Retaining Ownership of an 'Approval' Indicator Coin
I want to use some form of crypto-currency/blockchain algorithm to represent the notion of "endorsement", in the sense of approval.  One approach is to have a coin that you can give to a recipient, while retaining ownership and control of the coin, so that you can withdraw it at any time and give it to someone else.
Is there such a thing? Is there any reason why you can't do this with a blockchain?  What are the issues?

You can do this with a block chain. The easiest way is pro bably to form a payment that can be claimed by either of two public keys. One of them is yours used to take the coins back, the other of which has no corresponding private key but is used to indicate what you're endorsing.

Thanks, @DavidSchwartz,  do you know any implementations of such a scheme, where I could find out more?


text:
MULTIBIT: How to restore wallet with following information?
I am a noob to this whole BTC thing, so please bear with me.
I reformatted my computer and lost everything on it.
I decided I want to restore my multibit wallet but I only have the following info:

Secret words
Old password

I do not have a backup of the wallet file or whatever it is called.
My question is, how do I reopen this wallet with that information? It has a lot of BTCs it in and I really want to salvage it.
Thanks for reading!

The MultiBit HD wallet can be restored with just the seed words. Click "Restore" on the unlock screen and follow the instructions.

I would start with a data recovery service. As far as I know the password will only unlock the backup file, it's like having the key to a lockbox but not the lockbox!
A data recovery service might be able to retrieve the backup file (maybe!)


text:
Is there any bitcoin fork which goal is storing arbitrary information?
I know that there is Namecoin, which saves key:value pair.
Is thete other similar solutions?
Maybe for arbitrary textblocks?
Update: how they do it?
Delaware Blockchain Initiative to Streamline Record-Keeping for Private Companies
http://flip.it/wqxKJ

Storj is a blockchain based solution for encrypting and storing data. More information can be found about the project at storj.io

Storj don't save data in the blockchain but this is a good option.

Also Siacoin and Filecoin

Blockchains are more complicated than other distributed storage applications, because they have to enforce a global ordered history. It's very important whether Transaction A or Transaction B came first.
This is a huge design constraint, and it makes it much harder to design scaling solutions. Any prior block could potentially affect the validity of a new block, so new clients must download every old block and check them.
It doesn't make any sense to keep this constraint if you're designing a distributed data storage system. If there's a missing piece of data for an old block, the storage system should ignore that and keep going.

As I understand, most of DBs like PostgreSQL also ensure strong ordering of all transactions.

They don't enforce ordering between different databases. If I have a database tracking bird migrations, and you have a database tracking parts in a warehouse, there's no synchronization between them. If I start an operation before you start an operation, there's no guarantee that mine will finish before yours. In contrast, if my transaction gets into the blockchain before yours does, it will always run first, even on nodes that do initial block download years later. (Barring a re-org, anyway.)

Not exactly a Bitcoin fork, but the Factom project (factom.org) uses their own data structures and the Bitcoin blockchain to store information in an immutable way.
The user first creates a digital fingerprint of his data that gets into the Factom ledger/blockchain. Then, at regular intervals, the fingerprint of that ledger is published to the Bitcoin blockchain. This way, the amount and complexity of the data that can be much bigger than if that user puts the hash of his information directly on the Bitcoin blockchain, which is limited in size and expensive to publish to.
The project tries to give tools for proof of existence, proof of process and proof of audit.
This couple of videos may give you a good overview of the project:
Factor is Forever: https://www.youtube.com/embed/gVwT-XrrekY
How Does Factom Blockchain Technology Work: https://www.youtube.com/embed/MlzyI1bfyD4

But Factom does not store information actually. It storesonly signatures of documents.

You are right. It only stores hashes, not the actual information. I'm not sure if any projects tries to store the actual information in the blockchain, but that would be really inefficient.

Why not efficient? It may be something like forum based on blockchaine.

A blockchain is not efficient to store information because it generates thousands of copies of the information. In Bitcoin's case, transactions are small, but even with that many people argue that it doesn't make any sense to copy the payment for a coffee in thousands of copies of the blockchain that live in different computers.

Yes, there is no sense to save copies of coffee payment, but for some valuable information it may have sense.

It does not make sense. If your goal is data storage and burdening users with that data, you can't provide a competitive currency. Without valuable currency, you can't reward your miners for cooperation. Without incentive for miners, the immutability property of the chain disappears, and you could just have used bittorrent instead.


text:
Law / country specifics to start Ripple Gateway
There is requirement in https://ripple.com/wiki/Gateway_Integration_Manual
Gateways should comply with the BSA, have AML policies and require KYC information.
As i understand this requirements can be accomplished only by banks, funds or other financial institutes, am i right?
if so, what is the minimum starters level of capital need to make own gateway?

Contact a lawyer in your area. Anything anyone else says is irrelevant. I believe many areas allow businesses other than banks to do these things. Especially if they limit the amounts involved (e.g. where I am there is very little required for amounts less then a couple thousand).

According to Ripple the url https://ripple.com/wiki/Gateway_Integration_Manual for the Gateway Integration Manual is "DEPRECATED". Ripple says "This page has been replaced with the new Gateway Guide on ripple.com. Please refer to that document instead."
Here is their newer doc: https://ripple.com/build/gateway-guide/
Ripple does not prohibit those who are not "banks, funds or other financial institutes" from building a gateway. Just the opposite. It is in Ripples' best interest if widespread (Ripple compliant) adoption is made. In their example Ripple uses "a fictional online currency exchange named “ACME” and its users as examples, to show how ACME can expand its business to include being a Ripple gateway".
Businesses that link the Ripple network to the rest of the world such as "online financial services, such as payment systems and digital currency exchange" are businesses which could build a ripple gateway.
Looking at the list of Ripple Popular Gateways shows some of the types of businesses which could become gateways:
https://ripple.com/knowledge_center/gateway-information/
These include Panama Bitcoins (http://ptycoin.com/ripple), SnapSwap (https://snapswap.us/ and https://snapswap.eu/), and LakeBTC (https://www.lakebtc.com/) amongst many others.
To answer your query about "AML policies and require KYC information" the specific compliance regimes for this depend on the jurisdiction your ripple gateway lies within, and where your customers reside. For example if your theoretical Ripple Gateway was physically located within the USA then American AML KYC legislation would apply to your business. The same would apply if your gateway was outside of the US, but traded with US citizens residing in the USA. Other jurisdictions will have other legislation. Many crypto businesses have implemented their own brand of AML KYC specific to their own jurisdictional requirements.
There are more countries which do not have definitive crypto legislation than countries which do, so the applicability of traditional legislation itself is even in question for example the lack of a definition of what bitcoin is in each country can create a situation in which it is not clear whether or not legislation including AML or KYC applies to cryptocurrency, or even more undefined internationally, Ripples' legal financial exposure in transferring value globally in affected countries. This will be different in each country.
To answer your question "what is the minimum starters level of capital need to make own gateway?" the level of capital required would depend on the nature of the market you intended to serve. Different markets would require varying levels of financial commitment, the depth of the trust line you wanted to maintain would affect this, and the scope and geolocation of your organizational and technology infrastructure would also come into play.
Overall, it is highly beneficial to understand the law in each jurisdiction your Ripple Gateway will do business in. The opposite is also true.


text:
Bitcoin bet on price of Brent crude
Is there a place where I can bet on the price of Brent crude oil? For example, I bet 1 BTC and:

if the oil price increases by 1%, I will lose the bet.
if the oil price decreases by 1%, I will double my bet.

I am Russian and need a kind of insurance against the rouble falling. This bet will be a much cheaper solution than changing a lot of money into dollars or bitcoins.

That seems like an incredibly convoluted method. What if the oil price falls, but Bitcoin's value plummets? Why not just buy a currency future priced in some more stable currency?

It is not problem. If you live in russia and want to store you money safe you need to put half of money into US dollas, or euros. But it still  will be ok for 40/60 or 60/40. From mathematical point of view, function near maximum value does not change very much. For example cos(x)>0.99 if |x| < 0.1
So this protection scheme work even with bitcoin price change. May be I will win or loose extra money but in general it will be zero.
Main point of view - to spend less money into transaction costs.
If you try to transfer half of money into dollars, and later transfer back  you will loose 1-2%

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
What is currently the fastest way to buy a large amount Bitcoin?
I want to purchase on the order of $10k of Bitcoin in USD. I can't seem to a find a way of accomplishing this in less time than multiple weeks.
I've been looking at the major exchanges, and it seems to be bad news all around.
Mt.Gox requires you to verify your account before allowing incoming wire transfers. This could take 5 days. Then you are required to wait at least 5 business days for it to be processed, then wait an unspecified period for their AML checks to be completed.
Other exchanges I've looked at (such as btc-e, bitfloor, etc) allow incoming wire transfers, however don't specify how long the processing should take.
What is the quickest way I could theoretically accomplish this?

Related: http://bitcoin.stackexchange.com/questions/91/how-do-you-obtain-bitcoins

This might be your best bet... https://localbitcoins.com/

For 10k of bitcoins? I think most localbitcoins exchangers deal in much smaller amounts.

@NickODell: I've seen in person BTC transactions of that size take place at San Francisco Bitcoin meetups.

The AML laws in the US deliberately make this hard. Suddenly moving $10K of USD into BTC is exactly the kind of thing that makes the government worry about money laundering. So, without any case law protecting them, most exchanges aren't going to be willing to risk it without verifying your identity to help them get in compliance with the KYC/AML laws.
My personal opinion is that Bitfloor might be the fastest now, but I haven't tried everyone. But, even that is going to take a few days. And I started there with a smaller sum of money. $10K might hit some triggers that slow it down.
Or you could try to put several smaller transactions through bitinstant or localbitcoins, if you are more tolerant of fees and hassle. Those "non exchanges" won't be as concerned about AML.

Networking person to person, exchanges limit how much you can purchase at one time then you get taxed on it so exchanges are poor choice. Meetups or and look for tor services but be very careful


text:
BTC/USD price changes approximately the same way over many exchanges at the same time, how?
I have seen this many times, the same minute the price goes down on GDAX, it also has gone down on Bitfinex and Bitmex and Binance USDT etc. These exchanges have different prices, that's understandable, but how come they follow the same movement and not go all for each own path? I suspect there is something behind all this that brings them together even tho they are different places to trade on. I need to know what this is. Perhaps it's the price of the USD? Is it the same seller(s) selling at the same time over several exchanges?

To be more specific about the "arbitrage strategies" in Tanmay's answer:
Suppose there were a difference in price between two exchanges: at A the price is $10,000 and at B it is $10,100.  Then, in principle, someone could turn a quick and risk-free(*) profit by buying coins on A, transferring them to B, and selling them for the higher price.  This is called arbitrage.  As they do so, it will tend to drive up prices on A: the people who were offering coins for sale at $10,000 on A are having their offers accepted.  Eventually those offers will all be gone, and people who want to buy will have to take the next-best offer, which will be at a higher price.  Similarly, this strategy will also tend to drive down prices on B.
Arbitrage thus tends to make prices on different exchanges converge towards equilibrium.  And it can happen very fast, so significant differences in price, even if they should occur, don't tend to last very long.  Most of the time you see prices that are close together.
I have left out some details: for instance, the arbitrage strategy will incur transaction and trading costs, and it is not completely risk-free since prices could change in between trades.  This is part of why you don't see prices looking exactly the same at all times.  But the principle applies, and it's a fundamental principle in the study of finance.

There are a lot of traders who are are running arbitrage strategies. The whole premise is that, if the value of BTC relative to USD increases/decreases on one exchange due to a short term decrease/increase of supply, it should reflect on the other exchanges too (since at the end of the day, BTC is BTC regardless of what exchange it is being traded on).
So to answer your question- what brings all these exchanges together: it is a mixture of the same traders trading on all of the said exchanges and traders who hold the same short term opinion on the price of bitcoin.
Most of the arbitrage is done by algorithmic traders; human traders would be too slow to react fast enough to keep up with the market.


text:
Why bitcoin rise causes altcoins to drop?
Bitcoin has grown significantly in the last few days. From what I can see on Binance, price of the majority of altcoins has dropped significantly relative to bitcoin at the same time. I've been thinking that bitcoin rise should make another cryptocurrencies even more valuable but looks like there is an inverse correlation.
So why are the altcoins dropping related to bitcoin so heavily? Can anybody explain what's causing such relationship? Thank you.

What do you get when you sell an average altcoin? Do you get dollars? No. You get bitcoins. When people sell Altcoins, they get bitcoins => offer decreases => price rises.

You could also add that many altcoins propose advantages over Bitcoin. So when good Bitcoin gets good news it effectively gains against these coins.

@Alpha I really like your answer, that explained it to me pretty well. If I think that bitcoin price will rise, what, in your opinion, would be the best for me - sell all altcoins for BTC or continue holding altcoins assuming they will gain even more overtime? I'm just curious to know your point of view.

@Ivan Yurchenko, I know/learn about the technology of bitcoin but I don't want to tell you much about the market because I'm not an expert. But if you think that the BTC price could rise more than others (and increse its dominance ~ 40% at the moment) in the next weeks, changing only 50% of your altcoins to BTC is maybe not a bad solution. So you would still profit if an altcoin price explodes.

@Alpha Got it, thank you. I never thought about such opposite correlation, there were times where altcoins were rising alongside with bitcoin, but I think in that case it was due to a whale who carried the price. Do you mind adding me on Telegram to exchange ideas? As you can see, I'm far from being expert as well but I have researched into the market and had some profitable trades (i.e. I doubled my NANO investment and sold on .0016). Though currently I'm in negative in terms of BTC due to its recent rise (I hold alts only). If you would be interested you're welcome: t.me/lazermax

There are a few reasons, some examples (not limited to the below of course):
People will buy coins before forks, in the hope of claiming both coins and getting a "dividend" even if they don't believe the fork coin has value, they can simply sell at any price to get "free" money.  Possibly these people will then sell the coin they bought for bitcoin anyway, benefiting from the rise as other people bought in, and the sale of the fork.
Another possibility, if you're a BTC maximalist (and a "Whale"), is driving alt coins up, after the coin has pumped, you can sell back for BTC, increasing your BTC holdings.  Buying randomcoin and a few cents, driving the price up, or waiting for an announcement etc, will mean, again, you can safely move back to BTC increasing your holdings.  There's some circumstantial evidence of this happening.
People realising "gains" from alts, moving to BTC, people tell you to "diversify", but that's not always the best long term strategy, especially if your altcoins have experienced a gain, moving profits back to BTC (in lieu of FIAT) makes sense.
Dont forget the power of FOMO (Fear Of Missing Out), people will buy anything if the price is rising!

The one ane only reason is that everybody opting for BTC rather than altcoins. And this may create a bullrun for BTC but will also be the reason for the greatest dump ever. The pro traders will get the benefits out of it.


text:
Is bitcoinica.com planning to reopen after the 11th May 2012 theft?
On 11th May, 2012, 18,547 BTC were reported stolen from bitcoinica.com as stated here: https://bitcointalk.org/index.php?topic=81045.0
The bitcoinica.com website is unresponsive at the time of writing this. Are they planning to reopen? Have they stated whether their users' deposits will be refunded? If yes to either of those question, have they give a timeframe?

Zhou tong has stated here that reopening is being considered, with a time frame of several months.
He has also stated that deposits will be refunded; Most recently, he has stated that a claim page has been opened at https://claims.bitcoinica.com/, but at the time of this writing it seems to be unavailable.
Update: I can now access it.


text:
What are Forward Blocks?
Mark Friedenbach says "Bitcoin’s Block Size Can Be Increased Without Hard Fork".
Can someone ELI5 what are Forward Blocks?

From this week's Bitcoin Optech

One well-known method for soft forking an increase in the Bitcoin
  block size is extension blocks—a data structure that’s invisible to
  nodes that haven’t upgraded to the soft fork and so is not subject to
  their historic limits on block size. By itself, this is an undesirable
  method for increasing block size because preventing old nodes from
  seeing the transactions in the extension block also prevents them from
  being able to enforce any other consensus rules on those
  transactions—such as rules that prevent a malicious user from spending
  other users’ bitcoins or from creating more bitcoins than allowed by
  the 21 million bitcoin subsidy schedule.
However, one doesn’t need to increase block size to increase the
  amount of data that can be added to the block chain per minute—it’s
  also possible to increase capacity by increasing the frequency of
  blocks (reducing the average time between blocks). A method for gaming
  Bitcoin’s difficulty adjustment algorithm—called a time-warp attack—is
  well-known among experts and has been used successfully in
  demonstration attacks against Bitcoin’s testnet and real attacks
  against altcoins. (Note: although Bitcoin is technically vulnerable to
  this attack, it’d be a slow attack that would give the userbase a
  significant amount of time to respond.) By itself, increasing block
  frequency is also an undesirable method for increasing capacity
  because shorter block intervals increase the effectiveness of miners
  with large amounts of hashrate and so is likely to increase mining
  centralization.1
Perhaps disproving the saying that “two wrongs don’t make a right,”
  this talk describes a novel way of combining extension blocks and the
  time-warp attack to allow both upgraded nodes and old nodes to gain
  the same capacity increase and see all the same transactions for
  validation while simultaneously slightly reducing mining
  centralization risk. Upgraded nodes would validate one or more
  extension blocks (called “forward blocks”) that provide additional
  block space with a centralization-reducing 15 minute average interval,
  but the upgraded nodes would also restrict the time stamps in legacy
  blocks to ensure a permanent (but limited) time warp attack increased
  the frequency of legacy blocks enough to allow them to include the
  same transactions that previously appeared in the forward blocks.

Video / Transcript / Paper

Apparently, Mark Freidenbach refers to this work on Freicoin as the origins of ‘forward blocks’.
https://freicoinalliance.com/topic/638-changing-the-proof-of-work-algorithm/

No, that's orthogonal.


text:
What is 'birthday' in the context of BIP39 / Lightning seed generation?
In this talk about Lightning Network, roasbeef speaks about BIP39 as having no support for 'birthdays'. What does that mean?
https://www.youtube.com/watch?v=LXY0L8eeG3k minute 22

It simply means that BIP39 seeds have no way to tell you when they were created - If you need to check one for transactions, you have to start at the genesis block and work your way up to the present day.
This is in contrast to the traditional Bitcoin-qt wallet.dat, which maintains a date for when the address was created. Usually, it will not check for transactions for that address before that date (if the birthday is missing, it will check from genesis)


text:
Can I do blind refunds relatively reliably?
If I receive a Bitcoin payment, and do not have any other information about the sender, can I refund the payment with a decent degree of reliability?
The current state of things is that the general problem didn't have a catch all solution, but blockchain.info wallets, and I believe coinbase as well, allows you to send the tx back.
How reliable are blind refunds in practice?

I wouldn't try it. Take a refund address up-front, or have some means of contacting the user. Or request a signed message, from the address you received funds from, to the effect of "I authorize [ripper234's company or name or btc address], transaction number [], to refund address [], at [date/time]"

Not sure what you mean. What's wrong with sending the amount back to the sender?

@Luca: See the answer by CoinHeavy.

Do not use the raw protocol to issue refunds to addresses without first confirming with the sender that this is acceptable.
Most services generate unique addresses for each transaction.  Unless your customer owns the private key to the address from which the initial funds were sent, you can't be sure that they will receive the refund.  Different services have different implementations but if a customer sends you funds from a third party service that uses a single address for payments, the funds would be deducted from their account via a SQL entry and sent through a shared address.  The returned funds would be received by the service but not necessarily by your customer.
You should contact customers and have them confirm a refund address before sending.

If you can, try to get the refund address in advance. You can use Payment Protocol (a new feature introduced in 0.9) for this.


text:
Prevent rounding errors when displaying bitcoin values in javascript
What is the correct way to prevent Floating Point Precision errors when displaying bitcon values in javascript? I've seen many answers on the topic, but they all seem to have their drawbacks.
Here's what I've tried:
I've chosen to store bitcoin values in satoshis, then simply convert to float on the front end using simple math. Is this correct? I'm trying to avoid float precision errors. It seems to work as intended when testing with a calculator as reference, but I would love to know for sure.
var units = {

    // In satoshis
    coin: 100000000,

    format_to: function(val) {
        // 1 BTC = 10^8 Satoshis
        return (val / units.coin).toFixed(8);
    },

    format_from: function(val) {
        // Parse the string as float the multiply * coin.
        return (parseFloat(val) * units.coin);
    }

};

You should probably try to rephrase your question so that it is more generally applicable. Bitcoin SE is more suited towards learning than code review...

@StephenM347 ok, i've tried to improve the question.

Good idea on storing it in Satoshis. With anything involving money, you want to avoid floats due to rounding errors. The best way of doing this would be to parse the value in Satoshis as a string, then simply put a decimal place 8 digits from the end to get the value in Satoshis.
function convertToBTC(satoshis){
    var satoshi_string = satoshis.toString();
    var len_satoshi   = satoshi_string.length;
    if (len_satoshi < 9){
        concat_string = concat_zeroes(9 - len_satoshi, satoshi_string);
     }
    var btc_len = concat_string.length;
    var decimal_place = btc_len-8;
    var bitcoin_string = concat_string.slice(0,decimal_place).concat('.').concat(concat_string.slice(decimal_place, btc_len));
    return bitcoin_string;
}

function concat_zeroes(num_zeroes, string1){
    while(num_zeroes){
         string1 = '0'.concat(string1);
         num_zeroes -= 1;
    }
    return string1;
}


text:
Why does the BFL Single produce ~50% stales with P2Pool?
I've heard from users on bitcointalk forums that the BFL single doesn't work with P2Pool as it produces about 50% rejected shares, which is insanely high.
Why is this?
Is it possible that the hashing is not actually being done on the chip itself? And it's just taking place on an external server then submitted to the P2Pool node, which would maybe explain why the stale rate is so high due to network latency? (especially since BFL refuse to say what chip they are actually using in their Singles)
Thanks

I would hope that someone has tested the BFL on a node with no network connectivity (or heavily limited and monitored network connectivity) to rule out this kind of shenanigans.

@David Not necessary. The BFL units can run on CGminer, a separately developed mining program. It calls the low-level functions, not just "return hash". Unless the creator of CGminer (who has been around for quite a while) is in league with BFL, seems to me that eliminates the scheme you mentioned. BFL probably doesn't want to release the chip because they got some older model on a special sale, and want to keep the stock to themselves.

The BFL single produces high stale rates on P2Pool because of the way its firmware is designed. The BFL does 2^32 hashes and then reports any shares found. This takes it about 5 seconds.
With solo mining or typical pools, the work unit you get is valid for several minutes or until a new block is found (on average, one every ten minutes). So the average delay of 2-1/2 seconds between when you find a share and when it's reported has no effect. But P2Pool operates with an effectively much higher block rate because you're building blocks for the P2Pool chain.
Essentially, it comes down to which races you're trying to win and whether an average 2-1/2 second handicap matters.
Solo mining: You're trying to find a block before someone else does. That happens on average every 10 minutes. So your 2-1/2 second handicap costs you about .4%.
Conventional mining pool: You're trying to find a share before the block is invalid. You can find multiple shares inside the same work unit. Work units typically last at least 4 minutes. Worst case, your 2-1/2 second handicap costs you about 1% (usually less, especially if the pool has a forgiving stale policy).
P2Pool: You're trying to mine a P2Pool block before anyone else finds a share. Multiple shares in a work unit are useless as only one block can come next on the P2Pool chain. The average time to find a new P2Pool block is 10 seconds. Your 2-1/2 second handicap (plus loss of additional shares per block) costs you about 25%.
Unfortunately, all these penalties should be doubled because the same penalty hits you when a new block is first found. All your units spend, on average, an extra 2-1/2 seconds finishing their work on the old block. (Effectively, the entire 5 seconds spent on a work unit while a new block is found is wasted. Any shares found before the five seconds are over are wasted since it's too late to use them, and any shares found after the five seconds are over are wasted since they were based on the wrong block.)
The fix would be a simple firmware change to make the FPGA report a share as soon as one is found. That would solve half the problem. The next change would be to allow the FPGA to start working on a new work unit when a new one is available without having to finish the previous. That would solve the other half of the problem.

Great answer.  In summary: P2Pool blocks are found on average every 10 seconds.  The BFL takes 5 seconds to test a bunch of hashes.  If another peer finds a share during those 5 seconds (which happens 50% of the time) then the BFL's work is wasted.

Thanks for putting it so simply. And the fix would be two firmware changes: 1) When a new block is found elsewhere, you need to interrupt the current work and start working on the new block immediately. 2) When a new block is found locally, you need to report that block to the host immediately, not after searching the rest of the space.


text:
Does Litecoin have a higher chance of address collision than Bitcoin?
I assume Litecoin has different rules of generating addresses with Bitcoin, since all Litecoin addresses are 34-characters long which is different than Bitcoin.
Given that the rules for generating addresses are different, does Litecoin have a higher chance of address collision than Bitcoin?

When encoding the 20 byte public key hash with base-58, a prefix for the version byte is prepended. In Bitcoin, this version byte is 0x00 so that bitcoin addresses always start with a 1. In Litecoin, this version byte is 0x48 so that addresses always start with an L. This also has the side effect that the base58 encoding of these hashes is 26-34 characters for Bitcoin, and always 34 characters for Litecoin. See https://en.bitcoin.it/wiki/List_of_address_prefixes
But this doesn't change the fact that there is 20 bytes of information being encoded (addresses are really just human readable short-hand for this 20 bytes of data), and each possible combination has a unique encoding. Therefore, the chance of address collision is exactly the same in the two coins.


text:
bitcoind (JSON-RPC) returned HTTP 403 error, i don't know why
I set up bitcoind in Ubuntu 14.04 and I requested "getinfo",
but returned HTTP 403 error "FORBIDDEN". I don't know why...
The environment is below..
・Ubuntu is installed in Virtualbox and bitcoind is installed in the Ubuntu.
・The Host OS is Mac OS.
・The Host OS and the gest OS (Ubuntu) is connected host only adapter.
  (Host OS -> 10.0.2.2  Gest OS-> 192.168.33.33)
The bitcoin.conf is below

server=1
daemon=1
rpcallowip = 10.0.2.0/24
rpcuser=...
rpcpassword=...
rpcport=8332
txindex=1
keypool=100

From the browser, type "http://rpcuser:rpcpassword@192.168.33.33:8332/"
but it gives "Forbidden"
Forthermore, i tried to use easybitcoin.php (https://github.com/aceat64/EasyBitcoin-PHP/blob/master/easybitcoin.php),
but also the same like "HTTP_FORBIDDEN" "403"
Can you give me any advices?

Just to check, you are attempting http://user:password@192.168.33.33:8332/?

I tried , but the same, "Forbidden"

Your rpcallowip setting is 10.0.2.0, but you listed 10.0.2.2 as the host OS's IP. That could be your issue.


text:
Can we use google cloud service as a virtual server to mine bitcoins and is there any profitability of using their service?
Our computers has very less power when we compare it to the difficulty level of mining and it's very hard to get one bit coin. But to overcome the second issue there are "pools". But still the first issue remains the same. The ordinary desktop computers doesn't perform in a good manner relative to "performance/costs spent for the hardware". But, Google has a variety of cloud computing services such as "compute" "bigdata" etc. Can we use those services to mine bit coins in a profitable manner? if not provide reasons. and what kind of gross profitability will be there if I use their services?. Or if there are any other paid virtual machines we can hire to get a decent profits?
Are there any people(not billionaires, who invest in billions on hardware but people who can invest fairly decent amount of money for servers etc)  earn a gross profit and what their methods are to earn such profit
Further, I don't want to order specified hardware because when they arrive home, they will only be used as a room heater (eg: Butterflylabs). Furthermore, the recovery period of capital spend to buy those hardware is very long time, but within very short time, the bought hardware would be obsolete.
I'm trying to invest and make a fixed income without doing a job.

Your last sentence summarizes your post quite nicely: "I'm trying to invest and make a fixed income without doing a job." Maybe you should add: "and I'm expecting you to exactly tell me how."

@Jannes So, you say, that helping someone is bad ?

Trying to invest and make a fixed income without doing a job? realestate.stackoverflow.com

No, this will not work.  Cloud computing services give you the ability to rent any number of virtual servers, but each one has comparable capabilities to your desktop computer - you'd still be mining on a CPU.  The costs still outweigh the returns by a factor of thousands, if not millions.  You can rent more servers to get more mining power, but the costs increase linearly in the same way - this will only increase your losses.
The only possible way to profitably mine Bitcoin is with ASIC hardware, either buying it (and accepting that it will soon be obsolete) or contracting someone to run it on your behalf (which has many pitfalls of its own).

I'm trying to invest and make a fixed income without doing a job.

Anything related to cryptocurrency is really not a good way to make a fixed income - the inherent risks are simply too high.

the inherent risks are simply too high.So true. But I'd kick myself when 1 bitcoin will be worth 1 million €

@RaymondChenon: That's a terrible way to make investment decisions - you could apply the same flawed reasoning to justify any awful investment.

Can we use those services to mine bit coins in a profitable manner? if not provide reasons.

Because everyone would do so too, right?
I'll quote your the same paragraph you wrote:

Our computers has very less power when we compare it to the difficulty
  level of mining and it's very hard to get one bit coin. But to
  overcome the second issue there are "pools". But still the first issue
  remains the same. The ordinary desktop computers doesn't perform in a
  good manner relative to "performance/costs spent for the hardware"

I can provide references, but given the quote below, likewise, I'll forego the effort:

I'm trying to invest and make a fixed income without doing a job.

I know mate, and I'm telling you this isn't a money printing solution. If I come across as flippant I apologise

Now it is not profitable at all to mine Bitcoin on a VPS, but you can consider to mine some altcoins, such as Bytecoin, Monero or Gridcoin instead.


text:
Is reliance on a UTXO Set provided by other users dangerous?
One of the largest hurdles in my mind to increasing the number of full nodes operating is the startup cost related to downloading the blockchain.  A similar but less important (in my mind) issue is the amount of disk space required by the full blockchain.
In Would moving a transaction from an old block to a new one allow more pruning? Murch suggested that some assumptions be checked, and I think one of them was my assumption that it would be safe to rely on a UTXO Set provided by other users.  Given the answers to another assumption Murch suggested I check, it seems that the answer is "Not usually," but if there were a standard proof, such as a signed UTXO set or a UTXO Committment in the header, then the answer seems to change to "Yes!"
In any case, Murch suggested that the assumptions be checked, so I've created this question to check that one.

First, you can validate the utxo set for the most part using SPV proofs. Essentially, that would mean you need the 80-byte block headers from every block (currently 410,000 or so, which means a 32MB worth of headers) and every transaction in the utxo set can carry a merkle proof for the block that it was published in, which can help you validate the set. So getting a UTXO set along with the merkle proofs for each transaction would at the very least have some decent promises of validity.
Second, it's possible the UTXO set that someone else gives you can be either missing certain UTXOs or otherwise be sending spent transaction outputs. In that way, it's possible for another user to fool you about the UTXO set being complete.
Third, the danger in getting a UTXO set from someone else is that you compromise your own privacy. This is fine for a lot of people (those who use SPV wallets, for example), but it may not be for you.

How does getting the UTXO Set from someone else compromise your own privacy?  If you got the UTXO Set using the same technology that bit torrent uses, would that prevent that compromise?  Thanks!

The person you got the UTXO set from would know you control those addresses. If you're sufficiently anonymous (using Tor for example), then yes, it's possible to prevent that compromise. This is not that easy, though, as using something like bittorrent still exposes your IP address, which can be linked back to you.

I think you're imagining that I'm talking about a UTXO Set for a specific set of addresses. I'm not. I'm talking about the full UTXO set. If you knew that, then what addresses are you talking about?

In that case, there would only be the concern about whether the person providing the utxo set was being honest with you. It's annoying, but definitely do-able to verify each utxo with another person.