code:
@c The GNU Free Documentation License.
@center Version 1.3, 3 November 2008

@c This file is intended to be included within another document,
@c hence no sectioning command or @node.

@display
Copyright @copyright{} 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
@uref{http://fsf.org/}

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
@end display

@enumerate 0
@item
PREAMBLE

The purpose of this License is to make a manual, textbook, or other
functional and useful document @dfn{free} in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.

This License is a kind of ``copyleft'', which means that derivative
works of the document must themselves be free in the same sense.  It
complements the GNU General Public License, which is a copyleft
license designed for free software.

We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does.  But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book.  We recommend this License
principally for works whose purpose is instruction or reference.

@item
APPLICABILITY AND DEFINITIONS

This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
distributed under the terms of this License.  Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that
work under the conditions stated herein.  The ``Document'', below,
refers to any such manual or work.  Any member of the public is a
licensee, and is addressed as ``you''.  You accept the license if you
copy, modify or distribute the work in a way requiring permission
under copyright law.

A ``Modified Version'' of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
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A ``Secondary Section'' is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
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The ``Invariant Sections'' are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License.  If a
section does not fit the above definition of Secondary then it is not
allowed to be designated as Invariant.  The Document may contain zero
Invariant Sections.  If the Document does not identify any Invariant
Sections then there are none.

The ``Cover Texts'' are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License.  A Front-Cover Text may
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A ``Transparent'' copy of the Document means a machine-readable copy,
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Examples of suitable formats for Transparent copies include plain
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The ``Title Page'' means, for a printed book, the title page itself,
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The ``publisher'' means any person or entity that distributes copies
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A section ``Entitled XYZ'' means a named subunit of the Document whose
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of such a section when you modify the Document means that it remains a
section ``Entitled XYZ'' according to this definition.

The Document may include Warranty Disclaimers next to the notice which
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Disclaimers are considered to be included by reference in this
License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and has
no effect on the meaning of this License.

@item
VERBATIM COPYING

You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License.  You may not use
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You may also lend copies, under the same conditions stated above, and
you may publicly display copies.

@item
COPYING IN QUANTITY

If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document's license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
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the back cover.  Both covers must also clearly and legibly identify
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Copying with changes limited to the covers, as long as they preserve
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as verbatim copying in other respects.

If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
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If you publish or distribute Opaque copies of the Document numbering
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It is requested, but not required, that you contact the authors of the
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@item
MODIFICATIONS

You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it.  In addition, you must do these things in the Modified Version:

@enumerate A
@item
Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the Document).  You may use the same title as a previous version
if the original publisher of that version gives permission.

@item
List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified
Version, together with at least five of the principal authors of the
Document (all of its principal authors, if it has fewer than five),
unless they release you from this requirement.

@item
State on the Title page the name of the publisher of the
Modified Version, as the publisher.

@item
Preserve all the copyright notices of the Document.

@item
Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.

@item
Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the
terms of this License, in the form shown in the Addendum below.

@item
Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document's license notice.

@item
Include an unaltered copy of this License.

@item
Preserve the section Entitled ``History'', Preserve its Title, and add
to it an item stating at least the title, year, new authors, and
publisher of the Modified Version as given on the Title Page.  If
there is no section Entitled ``History'' in the Document, create one
stating the title, year, authors, and publisher of the Document as
given on its Title Page, then add an item describing the Modified
Version as stated in the previous sentence.

@item
Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and likewise
the network locations given in the Document for previous versions
it was based on.  These may be placed in the ``History'' section.
You may omit a network location for a work that was published at
least four years before the Document itself, or if the original
publisher of the version it refers to gives permission.

@item
For any section Entitled ``Acknowledgements'' or ``Dedications'', Preserve
the Title of the section, and preserve in the section all the
substance and tone of each of the contributor acknowledgements and/or
dedications given therein.

@item
Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles.  Section numbers
or the equivalent are not considered part of the section titles.

@item
Delete any section Entitled ``Endorsements''.  Such a section
may not be included in the Modified Version.

@item
Do not retitle any existing section to be Entitled ``Endorsements'' or
to conflict in title with any Invariant Section.

@item
Preserve any Warranty Disclaimers.
@end enumerate

If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant.  To do this, add their titles to the
list of Invariant Sections in the Modified Version's license notice.
These titles must be distinct from any other section titles.

You may add a section Entitled ``Endorsements'', provided it contains
nothing but endorsements of your Modified Version by various
parties---for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.

You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version.  Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity.  If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.

@item
COMBINING DOCUMENTS

You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy.  If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled ``History''
in the various original documents, forming one section Entitled
``History''; likewise combine any sections Entitled ``Acknowledgements'',
and any sections Entitled ``Dedications''.  You must delete all
sections Entitled ``Endorsements.''

@item
COLLECTIONS OF DOCUMENTS

You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all
other respects regarding verbatim copying of that document.

@item
AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an ``aggregate'' if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation's users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which are not themselves
derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half of
the entire aggregate, the Document's Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.

@item
TRANSLATION

Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections.  You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers.  In case of a disagreement between
the translation and the original version of this License or a notice
or disclaimer, the original version will prevail.

If a section in the Document is Entitled ``Acknowledgements'',
``Dedications'', or ``History'', the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.

@item
TERMINATION

You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License.  Any attempt
otherwise to copy, modify, sublicense, or distribute it is void, and
will automatically terminate your rights under this License.

However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
fails to notify you of the violation by some reasonable means prior to
60 days after the cessation.

Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does
not give you any rights to use it.

@item
FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions
of the GNU Free Documentation License from time to time.  Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns.  See
@uref{http://www.gnu.org/copyleft/}.

Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License ``or any later version'' applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
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number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation.  If the Document
specifies that a proxy can decide which future versions of this
License can be used, that proxy's public statement of acceptance of a
version permanently authorizes you to choose that version for the
Document.

@item
RELICENSING

``Massive Multiauthor Collaboration Site'' (or ``MMC Site'') means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works.  A
public wiki that anybody can edit is an example of such a server.  A
``Massive Multiauthor Collaboration'' (or ``MMC'') contained in the
site means any set of copyrightable works thus published on the MMC
site.

``CC-BY-SA'' means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.

``Incorporate'' means to publish or republish a Document, in whole or
in part, as part of another Document.

An MMC is ``eligible for relicensing'' if it is licensed under this
License, and if all works that were first published under this License
somewhere other than this MMC, and subsequently incorporated in whole
or in part into the MMC, (1) had no cover texts or invariant sections,
and (2) were thus incorporated prior to November 1, 2008.

The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009,
provided the MMC is eligible for relicensing.

@end enumerate

@page
@heading ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:

@smallexample
@group
  Copyright (C)  @var{year}  @var{your name}.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.
@end group
@end smallexample

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the ``with@dots{}Texts.''@: line with this:

@smallexample
@group
    with the Invariant Sections being @var{list their titles}, with
    the Front-Cover Texts being @var{list}, and with the Back-Cover Texts
    being @var{list}.
@end group
@end smallexample

If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.

@c Local Variables:
@c ispell-local-pdict: "ispell-dict"
@c End:


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2012, 2014, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt base16)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-60)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 vlist)
  #:use-module (ice-9 format)
  #:export (bytevector->base16-string
            base16-string->bytevector))

;;;
;;; Base 16.
;;;

(define (bytevector->base16-string bv)
  "Return the hexadecimal representation of BV's contents."
  (define len
    (bytevector-length bv))

  (let-syntax ((base16-chars (lambda (s)
                               (syntax-case s ()
                                 (_
                                  (let ((v (list->vector
                                            (unfold (cut > <> 255)
                                                    (lambda (n)
                                                      (format #f "~2,'0x" n))
                                                    1+
                                                    0))))
                                    v))))))
    (define chars base16-chars)
    (let loop ((i len)
               (r '()))
      (if (zero? i)
          (string-concatenate r)
          (let ((i (- i 1)))
            (loop i
                  (cons (vector-ref chars (bytevector-u8-ref bv i)) r)))))))

(define base16-string->bytevector
  (let ((chars->value (fold (lambda (i r)
                              (vhash-consv (string-ref (number->string i 16)
                                                       0)
                                           i r))
                            vlist-null
                            (iota 16))))
    (lambda (s)
      "Return the bytevector whose hexadecimal representation is string S."
      (define bv
        (make-bytevector (quotient (string-length s) 2) 0))

      (string-fold (lambda (chr i)
                     (let ((j (quotient i 2))
                           (v (and=> (vhash-assv chr chars->value) cdr)))
                       (if v
                           (if (zero? (logand i 1))
                               (bytevector-u8-set! bv j
                                                   (arithmetic-shift v 4))
                               (let ((w (bytevector-u8-ref bv j)))
                                 (bytevector-u8-set! bv j (logior v w))))
                           (error "invalid hexadecimal character" chr)))
                     (+ i 1))
                   0
                   s)
      bv)))

repo_name: Brendan/guile

license: mit


code:
;; -*- mode: scheme; coding: utf-8 -*-
;;
;; This module was renamed from (weinholt text base64 (1 0 20100612)) to
;; (guix base64) by Nikita Karetnikov <nikita@karetnikov.org> on
;; February 12, 2014.  It was later renamed to (gcrypt base64) by
;; Christopher Allan Webber <cwebber@dustycloud.org> on May 20, 2017.
;;
;; Some optimizations made by Ludovic Courtès <ludo@gnu.org>, 2015.
;; Turned into a Guile module (instead of R6RS).
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
;;
;; This file incorporates work covered by the following copyright and
;; permission notice:
;;
;;   Copyright © 2009, 2010 Göran Weinholt <goran@weinholt.se>
;;
;;   Permission is hereby granted, free of charge, to any person obtaining a
;;   copy of this software and associated documentation files (the "Software"),
;;   to deal in the Software without restriction, including without limitation
;;   the rights to use, copy, modify, merge, publish, distribute, sublicense,
;;   and/or sell copies of the Software, and to permit persons to whom the
;;   Software is furnished to do so, subject to the following conditions:
;;
;;   The above copyright notice and this permission notice shall be included in
;;   all copies or substantial portions of the Software.
;;
;;   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;;   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;;   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
;;   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;;   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
;;   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
;;   DEALINGS IN THE SOFTWARE.

;; RFC 4648 Base-N Encodings

(define-module (gcrypt base64)
  #:export (base64-encode
            base64-decode
            base64-alphabet
            base64url-alphabet
            get-delimited-base64
            put-delimited-base64)
  #:use-module (rnrs)
  #:use-module ((srfi srfi-13)
                #:select (string-index
                          string-prefix? string-suffix?
                          string-concatenate string-trim-both)))

(define-syntax define-alias
  (syntax-rules ()
    ((_ new old)
     (define-syntax new (identifier-syntax old)))))

;; Force the use of Guile's own primitives to avoid the overhead of its 'fx'
;; procedures.

(define-alias fxbit-field bitwise-bit-field)
(define-alias fxarithmetic-shift ash)
(define-alias fxarithmetic-shift-left ash)
(define-alias fxand logand)
(define-alias fxior logior)
(define-alias fxxor logxor)

(define base64-alphabet
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")

(define base64url-alphabet
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_")

(define base64-encode
  (case-lambda
    ;; Simple interface. Returns a string containing the canonical
    ;; base64 representation of the given bytevector.
    ((bv)
     (base64-encode bv 0 (bytevector-length bv) #f #f base64-alphabet #f))
    ((bv start)
     (base64-encode bv start (bytevector-length bv) #f #f base64-alphabet #f))
    ((bv start end)
     (base64-encode bv start end #f #f base64-alphabet #f))
    ((bv start end line-length)
     (base64-encode bv start end line-length #f base64-alphabet #f))
    ((bv start end line-length no-padding)
     (base64-encode bv start end line-length no-padding base64-alphabet #f))
    ((bv start end line-length no-padding alphabet)
     (base64-encode bv start end line-length no-padding alphabet #f))
    ;; Base64 encodes the bytes [start,end[ in the given bytevector.
    ;; Lines are limited to line-length characters (unless #f),
    ;; which must be a multiple of four. To omit the padding
    ;; characters (#\=) set no-padding to a true value. If port is
    ;; #f, returns a string.
    ((bv start end line-length no-padding alphabet port)
     (assert (or (not line-length) (zero? (mod line-length 4))))
     (let-values (((p extract) (if port
                                   (values port (lambda () (values)))
                                   (open-string-output-port))))
       (letrec ((put (if line-length
                         (let ((chars 0))
                           (lambda (p c)
                             (when (fx=? chars line-length)
                               (set! chars 0)
                               (put-char p #\linefeed))
                             (set! chars (fx+ chars 1))
                             (put-char p c)))
                         put-char)))
         (let lp ((i start))
           (cond ((= i end))
                 ((<= (+ i 3) end)
                  (let ((x (bytevector-uint-ref bv i (endianness big) 3)))
                    (put p (string-ref alphabet (fxbit-field x 18 24)))
                    (put p (string-ref alphabet (fxbit-field x 12 18)))
                    (put p (string-ref alphabet (fxbit-field x 6 12)))
                    (put p (string-ref alphabet (fxbit-field x 0 6)))
                    (lp (+ i 3))))
                 ((<= (+ i 2) end)
                  (let ((x (fxarithmetic-shift-left (bytevector-u16-ref bv i (endianness big)) 8)))
                    (put p (string-ref alphabet (fxbit-field x 18 24)))
                    (put p (string-ref alphabet (fxbit-field x 12 18)))
                    (put p (string-ref alphabet (fxbit-field x 6 12)))
                    (unless no-padding
                      (put p #\=))))
                 (else
                  (let ((x (fxarithmetic-shift-left (bytevector-u8-ref bv i) 16)))
                    (put p (string-ref alphabet (fxbit-field x 18 24)))
                    (put p (string-ref alphabet (fxbit-field x 12 18)))
                    (unless no-padding
                      (put p #\=)
                      (put p #\=)))))))
       (extract)))))

  ;; Decodes a base64 string. The string must contain only pure
  ;; unpadded base64 data.

(define base64-decode
  (case-lambda
    ((str)
     (base64-decode str base64-alphabet #f))
    ((str alphabet)
     (base64-decode str alphabet #f))
    ((str alphabet port)
     (unless (zero? (mod (string-length str) 4))
       (error 'base64-decode
              "input string must be a multiple of four characters"))
     (let-values (((p extract) (if port
                                   (values port (lambda () (values)))
                                   (open-bytevector-output-port))))
       (do ((i 0 (+ i 4)))
           ((= i (string-length str))
            (extract))
         (let ((c1 (string-ref str i))
               (c2 (string-ref str (+ i 1)))
               (c3 (string-ref str (+ i 2)))
               (c4 (string-ref str (+ i 3))))
           ;; TODO: be more clever than string-index
           (let ((i1 (string-index alphabet c1))
                 (i2 (string-index alphabet c2))
                 (i3 (string-index alphabet c3))
                 (i4 (string-index alphabet c4)))
             (cond ((and i1 i2 i3 i4)
                    (let ((x (fxior (fxarithmetic-shift-left i1 18)
                                    (fxarithmetic-shift-left i2 12)
                                    (fxarithmetic-shift-left i3 6)
                                    i4)))
                      (put-u8 p (fxbit-field x 16 24))
                      (put-u8 p (fxbit-field x 8 16))
                      (put-u8 p (fxbit-field x 0 8))))
                   ((and i1 i2 i3 (char=? c4 #\=)
                         (= i (- (string-length str) 4)))
                    (let ((x (fxior (fxarithmetic-shift-left i1 18)
                                    (fxarithmetic-shift-left i2 12)
                                    (fxarithmetic-shift-left i3 6))))
                      (put-u8 p (fxbit-field x 16 24))
                      (put-u8 p (fxbit-field x 8 16))))
                   ((and i1 i2 (char=? c3 #\=) (char=? c4 #\=)
                         (= i (- (string-length str) 4)))
                    (let ((x (fxior (fxarithmetic-shift-left i1 18)
                                    (fxarithmetic-shift-left i2 12))))
                      (put-u8 p (fxbit-field x 16 24))))
                   (else
                    (error 'base64-decode "invalid input"
                           (list c1 c2 c3 c4)))))))))))

(define (get-line-comp f port)
  (if (port-eof? port)
      (eof-object)
      (f (get-line port))))

  ;; Reads the common -----BEGIN/END type----- delimited format from
  ;; the given port. Returns two values: a string with the type and a
  ;; bytevector containing the base64 decoded data. The second value
  ;; is the eof object if there is an eof before the BEGIN delimiter.

(define (get-delimited-base64 port)
  (define (get-first-data-line port)
    ;; Some MIME data has header fields in the same format as mail
    ;; or http. These are ignored.
    (let ((line (get-line-comp string-trim-both port)))
      (cond ((eof-object? line) line)
            ((string-index line #\:)
             (let lp ()                           ;read until empty line
               (let ((line (get-line-comp string-trim-both port)))
                 (if (string=? line "")
                     (get-line-comp string-trim-both port)
                     (lp)))))
            (else line))))
  (let ((line (get-line-comp string-trim-both port)))
    (cond ((eof-object? line)
           (values "" (eof-object)))
          ((string=? line "")
           (get-delimited-base64 port))
          ((and (string-prefix? "-----BEGIN " line)
                (string-suffix? "-----" line))
           (let* ((type (substring line 11 (- (string-length line) 5)))
                  (endline (string-append "-----END " type "-----")))
             (let-values (((outp extract) (open-bytevector-output-port)))
               (let lp ((line (get-first-data-line port)))
                 (cond ((eof-object? line)
                        (error 'get-delimited-base64
                               "unexpected end of file"))
                       ((string-prefix? "-" line)
                        (unless (string=? line endline)
                          (error 'get-delimited-base64
                                 "bad end delimiter" type line))
                        (values type (extract)))
                       (else
                        (unless (and (= (string-length line) 5)
                                     (string-prefix? "=" line)) ;Skip Radix-64 checksum
                          (base64-decode line base64-alphabet outp))
                        (lp (get-line-comp string-trim-both port))))))))
          (else     ;skip garbage (like in openssl x509 -in foo -text output).
           (get-delimited-base64 port)))))

(define put-delimited-base64
  (case-lambda
    ((port type bv line-length)
     (display (string-append "-----BEGIN " type "-----\n") port)
     (base64-encode bv 0 (bytevector-length bv)
                    line-length #f base64-alphabet port)
     (display (string-append "\n-----END " type "-----\n") port))
    ((port type bv)
     (put-delimited-base64 port type bv 76))))


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt common)
  #:use-module (gcrypt package-config)
  #:use-module (system foreign)
  #:use-module (ice-9 match)
  #:export (gcrypt-version
            libgcrypt-func
            error-source error-string))

;;; Commentary:
;;;
;;; Common code for the GNU Libgcrypt bindings.  Loading this module
;;; initializes Libgcrypt as a side effect.
;;;
;;; Code:

(define libgcrypt-func
  (let ((lib (dynamic-link %libgcrypt)))
    (lambda (func)
      "Return a pointer to symbol FUNC in libgcrypt."
      (dynamic-func func lib))))

(define gcrypt-version
  ;; According to the manual, this function must be called before any other,
  ;; and it's not clear whether it can be called more than once.  So call it
  ;; right here from the top level.
  (let* ((ptr     (libgcrypt-func "gcry_check_version"))
         (proc    (pointer->procedure '* ptr '(*)))
         (version (pointer->string (proc %null-pointer))))
    (lambda ()
      "Return the version number of libgcrypt as a string."
      version)))

(define error-source
  (let* ((ptr  (libgcrypt-func "gcry_strsource"))
         (proc (pointer->procedure '* ptr (list int))))
    (lambda (err)
      "Return the error source (a string) for ERR, an error code as thrown
along with 'gcry-error'."
      (pointer->string (proc err)))))

(define error-string
  (let* ((ptr  (libgcrypt-func "gcry_strerror"))
         (proc (pointer->procedure '* ptr (list int))))
    (lambda (err)
      "Return the error description (a string) for ERR, an error code as
thrown along with 'gcry-error'."
      (pointer->string (proc err)))))

(define (gcrypt-error-printer port key args default-printer)
  "Print the gcrypt error specified by ARGS."
  (match args
    ((proc err)
     (format port "In procedure ~a: ~a: ~a"
             proc (error-source err) (error-string err)))))

(set-exception-printer! 'gcry-error gcrypt-error-printer)

;;; gcrypt.scm ends here


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2019 Brendan Tildesley <mail@brendan.scot>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt hash)
  #:use-module (gcrypt common)
  #:use-module (gcrypt utils)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 binary-ports)
  #:use-module (ice-9 hash-table)
  #:use-module (system foreign)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:export (gcrypt-hash
            open-hash-input-port
            open-hash-port
            port-hash
            file-hash

            ;; Deprecated
            sha1
            sha256
            open-sha256-port
            port-sha256
            file-sha256
            open-sha256-input-port))

;;; Commentary:
;;;
;;; Cryptographic hashes.
;;;
;;; Code:

;;;
;;; Hash.
;;;

;; Algorithm ID's can be found in libgcrypt's src/gcrypt.h.in.

;; I tried using gcry_md_get_algo_dlen get the hash lengths, but it does not
;; work for every available algorithm, so they are embedded here.
(define get-algorithm-data
  (let ((data
         (alist->hashq-table
          (list         ;; Algorithm ID | Hash length (bytes).
           (cons 'md5            (cons 1 16))
           (cons 'sha1           (cons 2 20))
           (cons 'rmd160         (cons 3 20))
           ;; 6 is TIGER from GnuPG < 1.3.2, so we use the tiger symbol for the updated
           ;; TIGER1.
           (cons 'sha256         (cons 8 32))
           (cons 'sha384         (cons 9 48))
           (cons 'sha512         (cons 10 64))
           (cons 'sha224         (cons 11 28))
           (cons 'md4            (cons 301 16))
           (cons 'crc32          (cons 302 4))
           (cons 'crc32-rfc1510  (cons 303 4))
           (cons 'crc24-rfc2440  (cons 304 3))
           (cons 'whirlpool      (cons 305 64))
           (cons 'tiger          (cons 306 24)) ; GCRY_MD_TIGER1
           (cons 'tiger2         (cons 307 24))
           (cons 'gostr3411-94   (cons 308 32))
           (cons 'stribog256     (cons 309 32))
           (cons 'stribog512     (cons 310 64))
           (cons 'gostr3411cp   (cons 311 32))
           (cons 'sha3-224       (cons 312 28))
           (cons 'sha3-256       (cons 313 32))
           (cons 'sha3-384       (cons 314 48))
           (cons 'sha3-512       (cons 315 64))
           (cons 'blake2b-512    (cons 318 64))
           (cons 'blake2b-384    (cons 319 48))
           (cons 'blake2b-256    (cons 320 32))
           (cons 'blake2b-160    (cons 321 20))
           (cons 'blake2s-256    (cons 322 32))
           (cons 'blake2s-224    (cons 323 28))
           (cons 'blake2s-160    (cons 324 20))
           (cons 'blake2s-128    (cons 325 16))
           ))))
    (lambda (algorithm)
      (let ((data (hashq-ref data algorithm)))
        (if data
            data
            (error (string-append
                    (symbol->string algorithm)
                    " does not appear to be a supported digest algorithm.")))))))

(define (hash-size algorithm)
  (cdr (get-algorithm-data algorithm)))

(define (algorithm-id algorithm)
  (car (get-algorithm-data algorithm)))

(define gcrypt-hash
  (let ((hash (pointer->procedure void
                                  (libgcrypt-func "gcry_md_hash_buffer")
                                  `(,int * * ,size_t))))
    (lambda* (bv algorithm #:optional size)
      "Return the hash HASH, using the digest ALGORITHM, of BV as a
bytevector. For variable length hashes, SIZE must be specified."
      (let* ((size (if size size (hash-size algorithm)))
             (digest (make-bytevector size)))
        (hash (algorithm-id algorithm)
              (bytevector->pointer digest)
              (bytevector->pointer bv)
              (bytevector-length bv))
        digest))))

(define (sha1 bv) (gcrypt-hash bv 'sha1))
(define (sha256 bv) (gcrypt-hash bv 'sha256))

(define open-hash-md
  (let ((open (pointer->procedure int
                                  (libgcrypt-func "gcry_md_open")
                                  `(* ,int ,unsigned-int))))
    (lambda (algorithm)
      (let* ((md  (bytevector->pointer (make-bytevector (sizeof '*))))
             (err (open md (algorithm-id algorithm) 0)))
        (if (zero? err)
            (dereference-pointer md)
            (throw 'gcrypt-error err))))))

(define md-write
  (pointer->procedure void
                      (libgcrypt-func "gcry_md_write")
                      `(* * ,size_t)))

(define md-read
  (pointer->procedure '*
                      (libgcrypt-func "gcry_md_read")
                      `(* ,int)))

(define md-close
  (pointer->procedure void
                      (libgcrypt-func "gcry_md_close")
                      '(*)))

(define (open-hash-port algorithm)
  "Return two values: an output port, and a thunk.  When the thunk is called,
it returns the hash (a bytevector) of all the data written to the
output port with the specified hash algorithm."
  (define hash-md
    (open-hash-md algorithm))

  (define digest #f)
  (define position 0)

  (define (finalize!)
    (let ((ptr (md-read hash-md 0)))
      (set! digest (bytevector-copy
                    (pointer->bytevector ptr (hash-size algorithm))))
      (md-close hash-md)))

  (define (write! bv offset len)
    (if (zero? len)
        (begin
          (finalize!)
          0)
        (let ((ptr (bytevector->pointer bv offset)))
          (md-write hash-md ptr len)
          (set! position (+ position len))
          len)))

  (define (get-position)
    position)

  (define (close)
    (unless digest
      (finalize!)))

  (values (make-custom-binary-output-port (symbol->string algorithm)
                                          write! get-position #f
                                          close)
          (lambda ()
            (unless digest
              (finalize!))
            digest)))

(define (port-hash algorithm port)
  "Return the hash (a bytevector) of all the data drained from PORT with the
specified hash algorithm."
  (let-values (((out get)
                (open-hash-port algorithm)))
    (dump-port port out)
    (close-port out)
    (get)))

(define (open-hash-input-port algorithm port)
  "Return an input port that wraps PORT and a thunk to get the hash of all the
data read from PORT.  The thunk always returns the same value."
  (define md
    (open-hash-md algorithm))

  (define (read! bv start count)
    (let ((n (get-bytevector-n! port bv start count)))
      (if (eof-object? n)
          0
          (begin
            (unless digest
              (let ((ptr (bytevector->pointer bv start)))
                (md-write md ptr n)))
            n))))

  (define digest #f)

  (define (finalize!)
    (let ((ptr (md-read md 0)))
      (set! digest (bytevector-copy
                    (pointer->bytevector ptr (hash-size algorithm))))
      (md-close md)))

  (define (get-hash)
    (unless digest
      (finalize!))
    digest)

  (define (unbuffered port)
    ;; Guile <= 2.0.9 does not support 'setvbuf' on custom binary input ports.
    ;; If you get a wrong-type-arg error here, the fix is to upgrade Guile.  :-)
    (setvbuf port _IONBF)
    port)

  (values (unbuffered (make-custom-binary-input-port (symbol->string algorithm) read! #f #f #f))
          get-hash))

(define (file-hash algorithm file)
  (call-with-input-file file (cut port-hash algorithm <>)))

(define (open-sha256-input-port port) (open-hash-input-port 'sha256 port))
(define (open-sha256-port) (open-hash-port 'sha256))
(define (port-sha256 port) (port-hash 'sha256 port))
(define (file-sha256 file) (file-hash 'sha256 file))

;;; hash.scm ends here


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt hmac)
  #:use-module (ice-9 hash-table)
  #:use-module (ice-9 format)
  #:use-module (ice-9 match)
  #:use-module (gcrypt base64)
  #:use-module (gcrypt common)
  #:use-module (gcrypt random)
  #:use-module (rnrs bytevectors)
  #:use-module (system foreign)
  #:export (sign-data
            sign-data-base64
            verify-sig verify-sig-base64
            gen-signing-key))

;;; HMAC
;;; ====

(define %no-error 0)  ; GPG_ERR_NO_ERROR

(define-wrapped-pointer-type <mac>
  mac?
  pointer->mac mac->pointer
  (lambda (mac port)
    (format port "#<mac ~x>"
            (pointer-address (mac->pointer mac)))))

(define %gcry-mac-open
  (pointer->procedure int (libgcrypt-func "gcry_mac_open")
                      `(* ,int ,unsigned-int *)))  ; gcry_mac_hd_t *HD, int ALGO,
                                                   ; unsigned int FLAGS, gcry_ctx_t CTX

(define mac-algorithms-mapping
  (alist->hashq-table
   `((sha256 . 101)
     (sha512 . 103)
     (sha3-256 . 116)
     (sha3-512 . 118))))

(define (mac-algo-ref sym)
  (hashq-ref mac-algorithms-mapping sym))

(define mac-algo-maclen
  (let ((proc (pointer->procedure
               int (libgcrypt-func "gcry_mac_get_algo_maclen")
               `(,int))))
    (lambda (sym)
      "Get expected length in bytes of mac yielded by algorithm SYM"
      (proc (mac-algo-ref sym)))))

(define (mac-open algorithm)
  "Create a <mac> object set to use ALGORITHM"
  (let* ((mac (bytevector->pointer (make-bytevector (sizeof '*))))
         (algo (mac-algo-ref algorithm))
         (err (%gcry-mac-open mac algo 0 %null-pointer)))
    (if (= err 0)
        (pointer->mac (dereference-pointer mac))
        (throw 'gcry-error 'mac-open err))))

(define %gcry-mac-setkey
  (pointer->procedure int (libgcrypt-func "gcry_mac_setkey")
                      `(* * ,size_t)))

(define (mac-setkey mac key)
  "Set the KEY on <mac> object MAC

In our case, KEY is either a string or a bytevector."
  (let* ((key (match key
                ((? bytevector? key)
                 key)
                ((? string? key)
                 (string->utf8 key))))
         (err (%gcry-mac-setkey (mac->pointer mac)
                                (bytevector->pointer key)
                                (bytevector-length key))))
    (if (= err 0)
        #t
        (throw 'gcry-error 'mac-setkey err))))

(define mac-close
  (let ((proc (pointer->procedure
               void (libgcrypt-func "gcry_mac_close")
               '(*))))  ; gcry_mac_hd_t H
    (lambda (mac)
      "Release all resources of MAC.

Running this on an already closed <mac> might segfault :)"
      (proc (mac->pointer mac)))))

(define mac-write
  (let ((proc (pointer->procedure
               int (libgcrypt-func "gcry_mac_write")
               `(* * ,size_t))))
    (lambda (mac obj)
      "Writes string or bytevector OBJ to MAC"
      (let* ((bv (match obj
                   ((? bytevector? obj)
                    obj)
                   ((? string? obj)
                    (string->utf8 obj))))
             (err (proc (mac->pointer mac)
                        (bytevector->pointer bv)
                        (bytevector-length bv))))
        (if (= err 0)
            #t
            (throw 'gcry-error 'mac-write err))))))

(define mac-read
  (let ((proc (pointer->procedure
               int (libgcrypt-func "gcry_mac_read")
               `(* * *))))
    (lambda (mac algorithm)
      "Get bytevector representing result of MAC's written, signed data"
      (define (int-bv* n)
        ;; Get the pointer to a bytevector holding an integer with this number
        (let ((bv (make-bytevector (sizeof int))))
          (bytevector-uint-set! bv 0 n (native-endianness) (sizeof int))
          (bytevector->pointer bv)))
      (let* ((bv-len (mac-algo-maclen algorithm))
             (bv (make-bytevector bv-len))
             (err (proc (mac->pointer mac)
                        (bytevector->pointer bv)
                        (int-bv* bv-len))))
        (if (= err 0)
            bv
            (throw 'gcry-error 'mac-read err))))))

;; GPG_ERR_CHECKSUM *should* be 10, but it seems to return here as
;; 16777226... unfortunately this is because we're pulling back an integer
;; rather than the gcry_error_t type.

(define mac-verify
  (let ((proc (pointer->procedure
               int (libgcrypt-func "gcry_mac_verify")
               `(* * ,size_t))))
    (lambda (mac bv)
      "Verify that BV matches result calculated in MAC

BV should be a bytevector with previously calculated data."
      (let ((err (proc (mac->pointer mac)
                       (bytevector->pointer bv)
                       (bytevector-length bv))))
        (if (= err 0)
            (values #t err)
            ;; TODO: This is WRONG!  See the comment above
            ;;   this procedure's definition for why.  If we could
            ;;   parse it as the appropriate GPG error, GPG_ERR_CHECKSUM
            ;;   should be 10.
            (values #f err))))))

(define* (sign-data key data #:key (algorithm 'sha512))
  "Signs DATA with KEY for ALGORITHM.  Returns a bytevector."
  (let ((mac (mac-open algorithm)))
    (mac-setkey mac key)
    (mac-write mac data)
    (let ((result (mac-read mac algorithm)))
      (mac-close mac)
      result)))

(define* (sign-data-base64 key data #:key (algorithm 'sha512))
  "Like sign-data, but conveniently encodes to base64."
  (base64-encode (sign-data key data #:algorithm algorithm)))

;; @@: Shouldn't this be "valid-sig?"
(define* (verify-sig key data sig #:key (algorithm 'sha512))
  "Verify that DATA with KEY matches previous signature SIG for ALGORITHM."
  (let ((mac (mac-open algorithm)))
    (mac-setkey mac key)
    (mac-write mac data)
    (let ((result (mac-verify mac sig)))
      (mac-close mac)
      result)))

(define* (verify-sig-base64 key data b64-sig #:key (algorithm 'sha512))
  (verify-sig key data
               (base64-decode b64-sig)
               #:algorithm algorithm))

(define* (gen-signing-key #:optional (key-length 128))
  "Generate a signing key (a bytevector).

KEY-LENGTH is the length, in bytes, of the key.  The default is 128.
This should be a multiple of 8."
  (gen-random-bv key-length %gcry-very-strong-random))


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt package-config)
  #:export (%libgcrypt
            %guile-gcrypt-package-name %guile-gcrypt-version))

(define %libgcrypt
  "@LIBGCRYPT@")

(define %guile-gcrypt-package-name
  "@PACKAGE_NAME@")

(define %guile-gcrypt-version
  "@PACKAGE_VERSION@")


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2013, 2014, 2015, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt pk-crypto)
  #:use-module (gcrypt base16)
  #:use-module (gcrypt common)

  #:use-module (system foreign)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 match)
  #:use-module (ice-9 rdelim)
  #:export (canonical-sexp?
            error-source
            error-string
            string->canonical-sexp
            canonical-sexp->string
            read-file-sexp
            number->canonical-sexp
            canonical-sexp-car
            canonical-sexp-cdr
            canonical-sexp-nth
            canonical-sexp-nth-data
            canonical-sexp-length
            canonical-sexp-null?
            canonical-sexp-list?
            bytevector->hash-data
            hash-data->bytevector
            key-type
            sign
            verify
            generate-key
            find-sexp-token
            canonical-sexp->sexp
            sexp->canonical-sexp)
  #:re-export (gcrypt-version))

;;; Commentary:
;;;
;;; Public key cryptographic routines from GNU Libgcrypt.
;;;;
;;; Libgcrypt uses "canonical s-expressions" to represent key material,
;;; parameters, and data.  We keep it as an opaque object to map them to
;;; Scheme s-expressions because (1) Libgcrypt sexps may be stored in secure
;;; memory, and (2) the read syntax is different.
;;;
;;; A 'canonical-sexp->sexp' procedure is provided nevertheless, for use in
;;; cases where it is safe to move data out of Libgcrypt---e.g., when
;;; processing ACL entries, public keys, etc.
;;;
;;; Canonical sexps were defined by Rivest et al. in the IETF draft at
;;; <http://people.csail.mit.edu/rivest/Sexp.txt> for the purposes of SPKI
;;; (see <http://www.ietf.org/rfc/rfc2693.txt>.)
;;;
;;; Code:

;; Libgcrypt "s-expressions".
(define-wrapped-pointer-type <canonical-sexp>
  canonical-sexp?
  naked-pointer->canonical-sexp
  canonical-sexp->pointer
  (lambda (obj port)
    ;; Don't print OBJ's external representation: we don't want key material
    ;; to leak in backtraces and such.
    (format port "#<canonical-sexp ~a | ~a>"
            (number->string (object-address obj) 16)
            (number->string (pointer-address (canonical-sexp->pointer obj))
                            16))))

(define finalize-canonical-sexp!
  (libgcrypt-func "gcry_sexp_release"))

(define-inlinable (pointer->canonical-sexp ptr)
  "Return a <canonical-sexp> that wraps PTR."
  (let* ((sexp (naked-pointer->canonical-sexp ptr))
         (ptr* (canonical-sexp->pointer sexp)))
    ;; Did we already have a <canonical-sexp> object for PTR?
    (when (equal? ptr ptr*)
      ;; No, so we can safely add a finalizer (in Guile 2.0.9
      ;; 'set-pointer-finalizer!' *adds* a finalizer rather than replacing the
      ;; existing one.)
      (set-pointer-finalizer! ptr finalize-canonical-sexp!))
    sexp))

(define string->canonical-sexp
  (let* ((ptr  (libgcrypt-func "gcry_sexp_new"))
         (proc (pointer->procedure int ptr `(* * ,size_t ,int))))
    (lambda (str)
      "Parse STR and return the corresponding gcrypt s-expression."

      ;; When STR comes from 'canonical-sexp->string', it may contain
      ;; characters that are really meant to be interpreted as bytes as in a C
      ;; 'char *'.  Thus, convert STR to ISO-8859-1 so the byte values of the
      ;; characters are preserved.
      (let* ((sexp (bytevector->pointer (make-bytevector (sizeof '*))))
             (err  (proc sexp (string->pointer str "ISO-8859-1") 0 1)))
        (if (= 0 err)
            (pointer->canonical-sexp (dereference-pointer sexp))
            (throw 'gcry-error 'string->canonical-sexp err))))))

(define-syntax GCRYSEXP_FMT_ADVANCED
  (identifier-syntax 3))

(define canonical-sexp->string
  (let* ((ptr  (libgcrypt-func "gcry_sexp_sprint"))
         (proc (pointer->procedure size_t ptr `(* ,int * ,size_t))))
    (lambda (sexp)
      "Return a textual representation of SEXP."
      (let loop ((len 1024))
        (let* ((buf  (bytevector->pointer (make-bytevector len)))
               (size (proc (canonical-sexp->pointer sexp)
                           GCRYSEXP_FMT_ADVANCED buf len)))
          (if (zero? size)
              (loop (* len 2))
              (pointer->string buf size "ISO-8859-1")))))))

(define (read-file-sexp file)
  "Return the canonical sexp read from FILE."
  (call-with-input-file file
    (compose string->canonical-sexp
             read-string)))

(define canonical-sexp-car
  (let* ((ptr  (libgcrypt-func "gcry_sexp_car"))
         (proc (pointer->procedure '* ptr '(*))))
    (lambda (lst)
      "Return the first element of LST, an sexp, if that element is a list;
return #f if LST or its first element is not a list (this is different from
the usual Lisp 'car'.)"
      (let ((result (proc (canonical-sexp->pointer lst))))
        (if (null-pointer? result)
            #f
            (pointer->canonical-sexp result))))))

(define canonical-sexp-cdr
  (let* ((ptr  (libgcrypt-func "gcry_sexp_cdr"))
         (proc (pointer->procedure '* ptr '(*))))
    (lambda (lst)
      "Return the tail of LST, an sexp, or #f if LST is not a list."
      (let ((result (proc (canonical-sexp->pointer lst))))
        (if (null-pointer? result)
            #f
            (pointer->canonical-sexp result))))))

(define canonical-sexp-nth
  (let* ((ptr  (libgcrypt-func "gcry_sexp_nth"))
         (proc (pointer->procedure '* ptr `(* ,int))))
    (lambda (lst index)
      "Return the INDEXth nested element of LST, an s-expression.  Return #f
if that element does not exist, or if it's an atom.  (Note: this is obviously
different from Scheme's 'list-ref'.)"
      (let ((result (proc (canonical-sexp->pointer lst) index)))
        (if (null-pointer? result)
            #f
            (pointer->canonical-sexp result))))))

(define (dereference-size_t p)
  "Return the size_t value pointed to by P."
  (bytevector-uint-ref (pointer->bytevector p (sizeof size_t))
                       0 (native-endianness)
                       (sizeof size_t)))

(define canonical-sexp-length
  (let* ((ptr  (libgcrypt-func "gcry_sexp_length"))
         (proc (pointer->procedure int ptr '(*))))
    (lambda (sexp)
      "Return the length of SEXP if it's a list (including the empty list);
return zero if SEXP is an atom."
      (proc (canonical-sexp->pointer sexp)))))

(define token-string?
  (let ((token-cs (char-set-union char-set:digit
                                  char-set:letter
                                  (char-set #\- #\. #\/ #\_
                                            #\: #\* #\+ #\=))))
    (lambda (str)
      "Return #t if STR is a token as per Section 4.3 of
<http://people.csail.mit.edu/rivest/Sexp.txt>."
      (and (not (string-null? str))
           (string-every token-cs str)
           (not (char-set-contains? char-set:digit (string-ref str 0)))))))

(define canonical-sexp-nth-data
  (let* ((ptr  (libgcrypt-func "gcry_sexp_nth_data"))
         (proc (pointer->procedure '* ptr `(* ,int *))))
    (lambda (lst index)
      "Return as a symbol (for \"sexp tokens\") or a bytevector (for any other
\"octet string\") the INDEXth data element (atom) of LST, an s-expression.
Return #f if that element does not exist, or if it's a list."
      (let* ((size*  (bytevector->pointer (make-bytevector (sizeof '*))))
             (result (proc (canonical-sexp->pointer lst) index size*)))
        (if (null-pointer? result)
            #f
            (let* ((len (dereference-size_t size*))
                   (str (pointer->string result len "ISO-8859-1")))
              ;; The sexp spec speaks of "tokens" and "octet strings".
              ;; Sometimes these octet strings are actual strings (text),
              ;; sometimes they're bytevectors, and sometimes they're
              ;; multi-precision integers (MPIs).  Only the application knows.
              ;; However, for convenience, we return a symbol when a token is
              ;; encountered since tokens are frequent (at least in the 'car'
              ;; of each sexp.)
              (if (token-string? str)
                  (string->symbol str)   ; an sexp "token"
                  (bytevector-copy       ; application data, textual or binary
                   (pointer->bytevector result len)))))))))

(define (number->canonical-sexp number)
  "Return an s-expression representing NUMBER."
  (let ((hex-number
         (match (number->string number 16)
           ;; Append a 0 if necessary.  For whatever reason gcrypt
           ;; rejects hex numbers that don't have an even number of
           ;; digits.
           ((? (lambda (s) (odd? (string-length s))) odd-string)
            (string-append "0" odd-string))
           (even-str even-str))))
    (string->canonical-sexp (string-append "#" hex-number "#"))))

(define* (bytevector->hash-data bv
                                #:optional
                                (hash-algo "sha256")
                                #:key (key-type 'ecc))
  "Given BV, a bytevector containing a hash of type HASH-ALGO, return an
s-expression suitable for use as the 'data' argument for 'sign'.  KEY-TYPE
must be a symbol: 'dsa, 'ecc, or 'rsa."
  (string->canonical-sexp
   (format #f "(data (flags ~a) (hash \"~a\" #~a#))"
           (case key-type
             ((ecc dsa) "rfc6979")
             ((rsa)     "pkcs1")
             (else (error "unknown key type" key-type)))
           hash-algo
           (bytevector->base16-string bv))))

(define (key-type sexp)
  "Return a symbol denoting the type of public or private key represented by
SEXP--e.g., 'rsa', 'ecc'--or #f if SEXP does not denote a valid key."
  (case (canonical-sexp-nth-data sexp 0)
    ((public-key private-key)
     (canonical-sexp-nth-data (canonical-sexp-nth sexp 1) 0))
    (else #f)))

(define* (hash-data->bytevector data)
  "Return two values: the hash value (a bytevector), and the hash algorithm (a
string) extracted from DATA, an sexp as returned by 'bytevector->hash-data'.
Return #f if DATA does not conform."
  (let ((hash (find-sexp-token data 'hash)))
    (if hash
        (let ((algo  (canonical-sexp-nth-data hash 1))
              (value (canonical-sexp-nth-data hash 2)))
          (values value (symbol->string algo)))
        (values #f #f))))

(define sign
  (let* ((ptr  (libgcrypt-func "gcry_pk_sign"))
         (proc (pointer->procedure int ptr '(* * *))))
    (lambda (data secret-key)
      "Sign DATA, a canonical s-expression representing a suitable hash, with
SECRET-KEY (a canonical s-expression whose car is 'private-key'.)  Note that
DATA must be a 'data' s-expression, as returned by
'bytevector->hash-data' (info \"(gcrypt) Cryptographic Functions\")."
      (let* ((sig (bytevector->pointer (make-bytevector (sizeof '*))))
             (err (proc sig (canonical-sexp->pointer data)
                        (canonical-sexp->pointer secret-key))))
        (if (= 0 err)
            (pointer->canonical-sexp (dereference-pointer sig))
            (throw 'gcry-error 'sign err))))))

(define verify
  (let* ((ptr  (libgcrypt-func "gcry_pk_verify"))
         (proc (pointer->procedure int ptr '(* * *))))
    (lambda (signature data public-key)
      "Verify that SIGNATURE is a signature of DATA with PUBLIC-KEY, all of
which are gcrypt s-expressions."
      (zero? (proc (canonical-sexp->pointer signature)
                   (canonical-sexp->pointer data)
                   (canonical-sexp->pointer public-key))))))

(define generate-key
  (let* ((ptr  (libgcrypt-func "gcry_pk_genkey"))
         (proc (pointer->procedure int ptr '(* *))))
    (lambda (params)
      "Return as an s-expression a new key pair for PARAMS.  PARAMS must be an
s-expression like: (genkey (rsa (nbits 4:2048)))."
      (let* ((key (bytevector->pointer (make-bytevector (sizeof '*))))
             (err (proc key (canonical-sexp->pointer params))))
        (if (zero? err)
            (pointer->canonical-sexp (dereference-pointer key))
            (throw 'gcry-error 'generate-key err))))))

(define find-sexp-token
  (let* ((ptr  (libgcrypt-func "gcry_sexp_find_token"))
         (proc (pointer->procedure '* ptr `(* * ,size_t))))
    (lambda (sexp token)
      "Find in SEXP the first element whose 'car' is TOKEN and return it;
return #f if not found."
      (let* ((token (string->pointer (symbol->string token)))
             (res   (proc (canonical-sexp->pointer sexp) token 0)))
        (if (null-pointer? res)
            #f
            (pointer->canonical-sexp res))))))

(define-inlinable (canonical-sexp-null? sexp)
  "Return #t if SEXP is the empty-list sexp."
  (null-pointer? (canonical-sexp->pointer sexp)))

(define (canonical-sexp-list? sexp)
  "Return #t if SEXP is a list."
  (or (canonical-sexp-null? sexp)
      (> (canonical-sexp-length sexp) 0)))

(define (canonical-sexp-fold proc seed sexp)
  "Fold PROC (as per SRFI-1) over SEXP, a canonical sexp."
  (if (canonical-sexp-list? sexp)
      (let ((len (canonical-sexp-length sexp)))
        (let loop ((index  0)
                   (result seed))
          (if (= index len)
              result
              (loop (+ 1 index)
                    ;; XXX: Call 'nth-data' *before* 'nth' to work around
                    ;; <https://bugs.g10code.com/gnupg/issue1594>, which
                    ;; affects 1.6.0 and earlier versions.
                    (proc (or (canonical-sexp-nth-data sexp index)
                              (canonical-sexp-nth sexp index))
                          result)))))
      (error "sexp is not a list" sexp)))

(define (canonical-sexp->sexp sexp)
  "Return a Scheme sexp corresponding to SEXP.  This is particularly useful to
compare sexps (since Libgcrypt does not provide an 'equal?' procedure), or to
use pattern matching."
  (if (canonical-sexp-list? sexp)
      (reverse
       (canonical-sexp-fold (lambda (item result)
                              (cons (if (canonical-sexp? item)
                                        (canonical-sexp->sexp item)
                                        item)
                                    result))
                            '()
                            sexp))

      ;; As of Libgcrypt 1.6.0, there's no function to extract the buffer of a
      ;; non-list sexp (!), so we first enlist SEXP, then get at its buffer.
      (let ((sexp (string->canonical-sexp
                   (string-append "(" (canonical-sexp->string sexp)
                                  ")"))))
        (or (canonical-sexp-nth-data sexp 0)
            (canonical-sexp-nth sexp 0)))))

(define (sexp->canonical-sexp sexp)
  "Return a canonical sexp equivalent to SEXP, a Scheme sexp as returned by
'canonical-sexp->sexp'."
  ;; XXX: This is inefficient, but the Libgcrypt API doesn't allow us to do
  ;; much better.
  (string->canonical-sexp
    (call-with-output-string
     (lambda (port)
       (define (write item)
         (cond ((list? item)
                (display "(" port)
                (for-each write item)
                (display ")" port))
               ((symbol? item)
                (format port " ~a" item))
               ((bytevector? item)
                (format port " #~a#"
                        (bytevector->base16-string item)))
               (else
                (error "unsupported sexp item type" item))))

       (write sexp)))))

;;; pk-crypto.scm ends here


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt random)
  #:use-module (gcrypt common)
  #:use-module (gcrypt base64)
  #:use-module (rnrs bytevectors)
  #:use-module (system foreign)
  #:use-module (ice-9 match)
  #:export (%gcry-weak-random
            %gcry-strong-random
            %gcry-very-strong-random
            gen-random-bv
            random-token))

(define %gcry-weak-random 0)  ; not used
(define %gcry-strong-random 1)
(define %gcry-very-strong-random 2)

(define %gcry-randomize
  (pointer->procedure void (libgcrypt-func "gcry_randomize")
                      `(* ,size_t ,int)))  ; buffer, length, level

(define* (gen-random-bv #:optional (bv-length 50)
                        (level %gcry-strong-random))
  (let* ((bv (make-bytevector bv-length))
         (bv-ptr (bytevector->pointer bv)))
    (%gcry-randomize bv-ptr bv-length %gcry-strong-random)
    bv))

(define %gcry-create-nonce
  (pointer->procedure void (libgcrypt-func "gcry_create_nonce")
                      `(* ,size_t)))  ; buffer, length

(define* (gen-random-nonce #:optional (bv-length 50))
  (let* ((bv (make-bytevector bv-length))
         (bv-ptr (bytevector->pointer bv)))
    (%gcry-create-nonce bv-ptr bv-length)
    bv))

(define* (random-token #:optional (bv-length 30)
                       (type 'strong))
  "Generate a random token.

Generates a token of bytevector BV-LENGTH, default 30.

The default TYPE is 'strong.  Possible values are:
 - strong: Uses libgcrypt's gcry_randomize procedure with level
   GCRY_STRONG_RANDOM (\"use this level for session keys and similar
   purposes\").
 - very-strong: Also uses libgcrypt's gcry_randomize procedure with level
   GCRY_VERY_STRONG_RANDOM (\"Use this level for long term key material\")
 - nonce: Uses libgcrypt's gcry_xcreate_nonce, whose documentation I'll
   just quote inline:

     Fill BUFFER with LENGTH unpredictable bytes.  This is commonly
     called a nonce and may also be used for initialization vectors and
     padding.  This is an extra function nearly independent of the other
     random function for 3 reasons: It better protects the regular
     random generator's internal state, provides better performance and
     does not drain the precious entropy pool."
  (let ((bv (match type
              ('strong
               (gen-random-bv bv-length %gcry-strong-random))
              ('very-strong
               (gen-random-bv bv-length %gcry-very-strong-random))
              ('nonce
               (gen-random-nonce bv-length)))))
    (base64-encode bv 0 bv-length #f #t base64url-alphabet)))


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gcrypt utils)
  #:use-module (rnrs bytevectors)
  #:use-module (rnrs io ports)
  #:export (dump-port))

(define* (dump-port in out
                    #:key (buffer-size 16384)
                    (progress (lambda (t k) (k))))
  "Read as much data as possible from IN and write it to OUT, using chunks of
BUFFER-SIZE bytes.  Call PROGRESS at the beginning and after each successful
transfer of BUFFER-SIZE bytes or less, passing it the total number of bytes
transferred and the continuation of the transfer as a thunk."
  (define buffer
    (make-bytevector buffer-size))

  (define (loop total bytes)
    (or (eof-object? bytes)
        (let ((total (+ total bytes)))
          (put-bytevector out buffer 0 bytes)
          (progress total
                    (lambda ()
                      (loop total
                            (get-bytevector-n! in buffer 0 buffer-size)))))))

  ;; Make sure PROGRESS is called when we start so that it can measure
  ;; throughput.
  (progress 0
            (lambda ()
              (loop 0 (get-bytevector-n! in buffer 0 buffer-size)))))


code:
\input texinfo
@c -*-texinfo-*-

@c %**start of header
@setfilename guile-gcrypt.info
@documentencoding UTF-8
@settitle Guile-Gcrypt Reference Manual
@c %**end of header

@include version.texi

@copying
Copyright @copyright{} 2018 Ludovic Courtès@*

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.  A
copy of the license is included in the section entitled ``GNU Free
Documentation License''.
@end copying

@dircategory The Algorithmic Language Scheme
@direntry
* Guile-Gcrypt: (guile-gcrypt).   Cryptographic library for Guile.
@end direntry

@titlepage
@title Guile-Gcrypt Reference Manual
@author The Guile-Gcrypt Developers

@page
@vskip 0pt plus 1filll
Edition @value{EDITION} @*
@value{UPDATED} @*

@insertcopying
@end titlepage

@contents

@c *********************************************************************
@node Top
@top Guile-Gcrypt

This manual documents Guile-Gcrypt, a Guile 2.x interface to the
GNU@tie{}Libgcrypt crytographic library, which is itself used by the
GNU@tie{}Privacy Guard (GPG).  @xref{Top,,, gcrypt, The Libgcrypt
Library}, for more information on Libgcrypt.

Actually this is very much a stub more than an actual manual.  Please
visit @uref{https://notabug.org/cwebber/guile-gcrypt} or email
@email{guile-user@@gnu.org} if you'd like to give a hand!

@menu
* Introduction::                      Getting started.
* Hash Functions::                    SHA1 and its friends.
* Message Authentication Codes::      HMAC.
* Public-Key Cryptography::           Signing and encrypting.
* Random Numbers::                    Generating random numbers.
* Miscellany::                        Bonuses!

* GNU Free Documentation License::    The license of this manual.
* Index::                             Index of concepts and procedures.
@end menu

@node Introduction
@chapter Introduction

@cindex modules
Libgcrypt functionality is exposed in a set of Guile modules in the
@code{(gcrypt @dots{})} name space (@pxref{Modules,,, guile, The Guile
Reference Manual}).  Each module provides specific functionality from
Libgcrypt.  For example, the following code imports cryptographic hash
functions:

@lisp
(use-modules (gcrypt hash))
@end lisp

@findex string->canonical-sexp
Procedure names are not a direct mapping of the C function names;
instead, more ``Schemey'' names are chosen for your enjoyment.  For
example, the Libgcrypt's C function called @code{gcry_sexp_new} is
exposed in Scheme as the @code{string->canonical-sexp} procedure in the
@code{(gcrypt pk-crypto)}---more pleasant to the eye, no?

@cindex error handling
@cindex exceptions
When an error occurs, Guile-Gcrypt procedures raise an exception with
the key @code{'gcry-error} (@pxref{Exceptions,,, guile, The Guile
Reference Manual}).  Exceptions have two arguments: the name of the
procedure that raised it, and an @dfn{error number}.  The @code{(gcrypt
common)} modules provides procedures to interpret error numbers:
@code{error-source} and @code{error-string}.  Here's an example showing
how you could report Libgcrypt errors to the user:

@lisp
(catch 'gcry-error
  (lambda ()
    ;; Do something with Guile-Gcrypt...
    )
  (lambda (key proc err)
    (format (current-error-port) "error from '~a': ~a: ~a~%"
            proc (error-source err) (error-string err))))
@end lisp

These two procedures are detailed below.

@deffn {Scheme Procedure} error-source @var{err}
Return the error source (a string) for @var{err}, an error code as thrown
along with @code{gcry-error}.
@end deffn

@deffn {Scheme Procedure} error-string @var{err}
Return the error description (a string) for @var{err}, an error code as
thrown along with @code{gcry-error}.
@end deffn

@node Hash Functions
@chapter Hash Functions

The @code{(gcrypt hash)} module exports @dfn{cryptographic hash
functions} (@pxref{Hashing,,, gcrypt, The Libgcrypt Library}).
Currently only a small subset of hash functions is exposed by
Guile-Gcrypt, listed here.

@deffn {Scheme Procedure} sha1 @var{bv}
@deffnx {Scheme Procedure} sha256 @var{bv}
Return the SHA1 or SHA256 hash of the data in @var{bv}, a bytevector.
The returned hash is itself represented as a bytevector
(@pxref{Bytevectors,,, guile, The Guile Reference Manual}).
@end deffn

@deffn {Scheme Procedure} open-sha256-port
Return two values: an output port, and a thunk.  When the thunk is called,
it returns the SHA256 hash (a bytevector) of all the data written to the
output port.
@end deffn

@deffn {Scheme Procedure} port-sha256 @var{port}
Return the SHA256 hash (a bytevector) of all the data drained from
@var{port}.
@end deffn

@deffn {Scheme Procedure} file-sha256 @var{file}
Return the SHA256 hash (a bytevector) of @var{file}.
@end deffn

@deffn {Scheme Procedure} open-sha256-input-port @var{port}
Return an input port that wraps @var{port} and a thunk to get the hash of all the
data read from @var{port}.  The thunk always returns the same value.
@end deffn

@node Message Authentication Codes
@chapter Message Authentication Codes

The @code{(gcrypt hmac)} module provides procedures to deal with
@dfn{message authentication codes} or @dfn{MACs} (@pxref{Message
Authentication Codes,,, gcrypt, The Libgcrypt Library}).

@node Public-Key Cryptography
@chapter Public-Key Cryptography

@cindex public-key cryptography
@cindex canonical S-expressions
Tools for @dfn{public-key cryptography} (@pxref{Public Key
cryptography,,, gcrypt, The Libgcrypt Library}) are provided by the
@code{(gcrypt pk-crypto)} module.

This module includes code to deal with @dfn{canonical S-expressions} (or
``sexps'') @uref{http://people.csail.mit.edu/rivest/Sexp.txt, as defined
by Rivest et al.}  They are used to specify public-key cryptography
parameters (@pxref{Used S-expressions,,, gcrypt, The Libgcrypt
Library}).  Naturally, there are procedures to convert a Guile sexp to a
Libgcrypt canonical sexp object and @i{vice versa}:

@deffn {Scheme Procedure} canonical-sexp->sexp @var{sexp}
Return a Scheme sexp corresponding to @var{sexp}.  This is particularly useful to
compare sexps (since Libgcrypt does not provide an @code{equal?} procedure), or to
use pattern matching.
@end deffn

@deffn {Scheme Procedure} sexp->canonical-sexp @var{sexp}
Return a canonical sexp equivalent to @var{sexp}, a Scheme sexp as returned by
@code{canonical-sexp->sexp}.
@end deffn

@deffn {Scheme Procedure} string->canonical-sexp @var{str}
Parse @var{str} and return the corresponding gcrypt s-expression.
@end deffn

@deffn {Scheme Procedure} canonical-sexp->string @var{sexp}
Return a textual representation of @var{sexp}.
@end deffn

@cindex key pair generation
@cindex generating key pairs
For example, here is how you would generate an Ed25519 key pair and
display its public key as a canonical sexp:

@findex generate-key
@findex find-sexp-token
@lisp
(use-modules (gcrypt pk-crypto))

(let* ((parameters (sexp->canonical-sexp
                     '(genkey
                        (ecdsa (curve Ed25519) (flags rfc6979)))))
       (pair       (generate-key parameters))
       (public     (find-sexp-token pair 'public-key)))
  (display (canonical-sexp->string public)))

@print{}
(public-key
 (ecc
  (curve Ed25519)
  (q #141D9C42@dots{}CE853B#)
  )
 )
@end lisp

Notice that we did @emph{not} pass @code{pair} to
@code{canonical-sexp->sexp}: that would have worked, but the private key
would have been copied to memory managed by the garbage collector, which
is a security risk---Libgcrypt might have stored the private key in
so-called ``secure memory'' protected from swap, whereas Guile does no
such thing for its objects (@pxref{Initializing the library, secure
memory,, gcrypt, The Libgcrypt Library}).  Thus the above example uses
@code{find-sexp-token}, which accesses the canonical sexp directly, in
search for the @code{public-key} symbol.

@xref{Used S-expressions,,, gcrypt, The Libgcrypt Library}, for more
information on the canonical sexps consumed and produced by public-key
cryptography functions.

@node Random Numbers
@chapter Random Numbers
The @code{(gcrypt random)} module provides tools to generate random
number of different quality levels (@pxref{Random Numbers,,, gcrypt, The
Libgcrypt Library}).

@node Miscellany
@chapter Miscellany

As a bonus, Guile-Gcrypt provides two useful modules:

@itemize
@item @code{(gcrypt base16)} provides procedures to encode and decode
hexadecimal strings;

@item @code{(gcrypt base64)} provides procedures to encode and decode
base64 strings as defined in @uref{https://tools.ietf.org/html/rfc4648,
RFC 4648}.
@end itemize

@c *********************************************************************
@node GNU Free Documentation License
@appendix GNU Free Documentation License
@cindex license, GNU Free Documentation License
@include fdl-1.3.texi

@c *********************************************************************
@node Index
@unnumbered Index
@printindex cp
@syncodeindex tp fn
@syncodeindex vr fn
@printindex fn

@bye

@c Local Variables:
@c ispell-local-dictionary: "american";
@c End:


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(use-modules (guix packages)
             (guix build-system gnu)
             (guix download)
             (guix git-download)
             (guix gexp)
             ((guix build utils) #:select (with-directory-excursion))
             (gnu packages)
             (gnu packages autotools)
             (gnu packages base)
             (gnu packages guile)
             (gnu packages pkg-config)
             (gnu packages texinfo)
             (gnu packages gnupg)
             (guix licenses))

(define %source-dir (dirname (current-filename)))

(define guile-gcrypt
  (package
    (name "guile-gcrypt")
    (version "git")
    (source (local-file %source-dir
                        #:recursive? #t
                        #:select? (git-predicate %source-dir)))
    (build-system gnu-build-system)
    (arguments
     '(#:phases
       (modify-phases %standard-phases
         (add-after 'unpack 'bootstrap
           (lambda _ (zero? (system* "sh" "bootstrap.sh")))))))
    (native-inputs
     `(("pkg-config" ,pkg-config)
       ("autoconf" ,autoconf)
       ("automake" ,automake)
       ("texinfo" ,texinfo)))
    (inputs
     `(("guile" ,guile-2.2)
       ("libgcrypt" ,libgcrypt)))
    (home-page "https://notabug.org/cwebber/guile-gcrypt")
    (synopsis "Crypto library for Guile using libgcrypt")
    (description "guile-gcrypt uses Guile's foreign function interface to wrap
libgcrypt to provide a variety of encryption tooling.")
    (license gpl3+)))

guile-gcrypt


code:
dnl GNU Guix --- Functional package management for GNU
dnl Copyright © 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
dnl Copyright © 2014 Mark H Weaver <mhw@netris.org>
dnl
dnl This file is part of GNU Guix.
dnl
dnl GNU Guix is free software; you can redistribute it and/or modify it
dnl under the terms of the GNU General Public License as published by
dnl the Free Software Foundation; either version 3 of the License, or (at
dnl your option) any later version.
dnl
dnl GNU Guix is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
dnl GNU General Public License for more details.
dnl
dnl You should have received a copy of the GNU General Public License
dnl along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

dnl GUIX_ASSERT_LIBGCRYPT_USABLE
dnl
dnl Assert that GNU libgcrypt is usable from Guile.
AC_DEFUN([GUIX_ASSERT_LIBGCRYPT_USABLE],
  [AC_CACHE_CHECK([whether $LIBGCRYPT can be dynamically loaded],
    [guix_cv_libgcrypt_usable_p],
    [GUILE_CHECK([retval],
      [(dynamic-func \"gcry_md_hash_buffer\" (dynamic-link \"$LIBGCRYPT\"))])
     if test "$retval" = 0; then
       guix_cv_libgcrypt_usable_p="yes"
     else
       guix_cv_libgcrypt_usable_p="no"
     fi])

   if test "x$guix_cv_libgcrypt_usable_p" != "xyes"; then
     AC_MSG_ERROR([GNU libgcrypt does not appear to be usable; see `--with-libgcrypt-prefix' and `README'.])
   fi])

dnl GUIX_LIBGCRYPT_LIBDIR VAR
dnl
dnl Attempt to determine libgcrypt's LIBDIR; store the result in VAR.
AC_DEFUN([GUIX_LIBGCRYPT_LIBDIR], [
  AC_PATH_PROG([LIBGCRYPT_CONFIG], [libgcrypt-config])
  AC_CACHE_CHECK([libgcrypt's library directory],
    [guix_cv_libgcrypt_libdir],
    [if test "x$LIBGCRYPT_CONFIG" != "x"; then
       guix_cv_libgcrypt_libdir=`$LIBGCRYPT_CONFIG --libs | grep -e -L | sed -e "s/.*-L\([[^ ]]\+\)[[[:blank:]]]\+-lgcrypt.*/\1/g"`
     else
       guix_cv_libgcrypt_libdir=""
     fi])
  $1="$guix_cv_libgcrypt_libdir"
])


code:
#!/bin/sh

# srt2vtt --- SRT to WebVTT converter
# Copyright © 2015 David Thompson <davet@gnu.org>
# Copyright © 2015, 2016 Christopher Allan Webber <cwebber@dustycloud.org>
#
# srt2vtt is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# srt2vtt is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with srt2vtt.  If not, see <http://www.gnu.org/licenses/>.

abs_top_srcdir="`cd "@abs_top_srcdir@" > /dev/null; pwd`"
abs_top_builddir="`cd "@abs_top_builddir@" > /dev/null; pwd`"

GUILE_LOAD_COMPILED_PATH="$abs_top_builddir${GUILE_LOAD_COMPILED_PATH:+:}$GUILE_LOAD_COMPILED_PATH"
GUILE_LOAD_PATH="$abs_top_builddir:$abs_top_srcdir${GUILE_LOAD_PATH:+:}:$GUILE_LOAD_PATH"
export GUILE_LOAD_COMPILED_PATH GUILE_LOAD_PATH

PATH="$abs_top_builddir/scripts:$PATH"
export PATH

GUILE_GCRYPT_DATADIR="$abs_top_builddir/data"
export GUILE_GCRYPT_DATADIR

exec "$@"


code:
;;; guile-gcrypt --- crypto tooling for guile
;;; Copyright © 2012, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (test-base16)
  #:use-module (gcrypt base16)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-64)
  #:use-module (rnrs bytevectors))

(test-begin "base16")

(test-assert "bytevector->base16-string->bytevector"
  (every (lambda (bv)
           (equal? (base16-string->bytevector
                    (bytevector->base16-string bv))
                   bv))
         (map string->utf8 '("" "f" "fo" "foo" "foob" "fooba" "foobar"))))

(test-end "base16")


code:
;;; guile-gcrypt --- crypto tooling for guile
;;;
;;; Code taken from:
;;;
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.org>
;;;
;;; This file is part of guile-gcrypt.
;;;
;;; guile-gcrypt is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; guile-gcrypt is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with guile-gcrypt.  If not, see <http://www.gnu.org/licenses/>.

(define-module (test-base64)
  #:use-module (gcrypt base64)
  #:use-module (rnrs bytevectors)
  #:use-module (srfi srfi-64))

(define (string->base64 str)
  (base64-encode (string->utf8 str)))

;;; Test vectors from <https://tools.ietf.org/rfc/rfc4648.txt>.

(test-begin "base64")

(test-equal "empty string"
  (string->base64 "")
  "")

(test-equal "f"
  (string->base64 "f")
  "Zg==")

(test-equal "fo"
  (string->base64 "fo")
  "Zm8=")

(test-equal "foo"
  (string->base64 "foo")
  "Zm9v")

(test-equal "foob"
  (string->base64 "foob")
  "Zm9vYg==")

(test-equal "fooba"
  (string->base64 "fooba")
  "Zm9vYmE=")

(test-equal "foobar"
  (string->base64 "foobar")
  "Zm9vYmFy")

(test-end "base64")