From 804e742557dbafe85ae65c072ce96ef13f4bf972 Mon Sep 17 00:00:00 2001 From: Matt Birkholz Date: Thu, 2 Nov 2017 16:56:48 -0700 Subject: [PATCH] blowfish plugin: Add texinfo manual, scraped from OpenSSL manpages. --- src/blowfish/Makefile.am | 4 +- src/blowfish/blowfish.scm | 41 -- src/blowfish/mit-scheme-blowfish.texi | 723 ++++++++++++++++++++++++++ 3 files changed, 725 insertions(+), 43 deletions(-) create mode 100644 src/blowfish/mit-scheme-blowfish.texi diff --git a/src/blowfish/Makefile.am b/src/blowfish/Makefile.am index cc67d56f6..e0b129c29 100644 --- a/src/blowfish/Makefile.am +++ b/src/blowfish/Makefile.am @@ -41,8 +41,8 @@ binaries = @MIT_SCHEME_BCIs@ @MIT_SCHEME_COMs@ scmlib_sub_DATA = $(sources) $(binaries) scmlib_sub_DATA += make.scm @MIT_SCHEME_PKD@ -#info_TEXINFOS = mit-scheme-blowfish.texi -#AM_MAKEINFOHTMLFLAGS = --no-split +info_TEXINFOS = mit-scheme-blowfish.texi +AM_MAKEINFOHTMLFLAGS = --no-split AM_CPPFLAGS = -I@MIT_SCHEME_INCLUDEDIR@ AM_CFLAGS = @MIT_CFLAGS@ diff --git a/src/blowfish/blowfish.scm b/src/blowfish/blowfish.scm index cd5869dd6..7cab6e675 100644 --- a/src/blowfish/blowfish.scm +++ b/src/blowfish/blowfish.scm @@ -49,9 +49,6 @@ USA. (C-include "blowfish") (define (blowfish-set-key bytes) - ;; Generate a Blowfish key from BYTES. - ;; BYTES must be 72 bytes or less in length. - ;; For text-string keys, use MD5 on the text, and pass the digest here. (guarantee bytevector? bytes 'blowfish-set-key) (let ((len (bytevector-length bytes))) (if (> len 72) @@ -61,24 +58,12 @@ USA. key))) (define (blowfish-ecb input output key encrypt?) - ;; Apply Blowfish in Electronic Code Book mode. - ;; INPUT is an 8-byte bytevector. - ;; OUTPUT is an 8-byte bytevector. - ;; KEY is a Blowfish key. - ;; ENCRYPT? says whether to encrypt (#T) or decrypt (#F). (guarantee-bfkey key 'blowfish-ecb) (guarantee-8byte-arg input 'blowfish-ecb) (guarantee-8byte-arg output 'blowfish-ecb) (C-call "BF_ecb_encrypt" input output key (bf-de/encrypt encrypt?))) (define (blowfish-cbc input output key init-vector encrypt?) - ;; Apply Blowfish in Cipher Block Chaining mode. - ;; INPUT is a bytevector whose length is a multiple of 8 bytes. - ;; OUTPUT is a bytevector whose length is the same as INPUT. - ;; KEY is a Blowfish key. - ;; INIT-VECTOR is an 8-byte bytevector; it is modified after each call. - ;; The value from any call may be passed in to a later call. - ;; ENCRYPT? says whether to encrypt (#T) or decrypt (#F). (guarantee-init-vector init-vector 'blowfish-cbc) (guarantee-bfkey key 'blowfish-cbc) (guarantee-8Xbyte-arg input 'blowfish-cbc) @@ -92,18 +77,6 @@ USA. (define (blowfish-cfb64 input istart iend output ostart key init-vector num encrypt?) - ;; Apply Blowfish in Cipher Feed-Back mode. - ;; (INPUT,ISTART,IEND) is an arbitrary bytevector range. - ;; OUTPUT is a bytevector. - ;; OSTART says where to start writing in OUTPUT. - ;; KEY is a Blowfish key. - ;; INIT-VECTOR is an 8-byte bytevector; it is modified after each call. - ;; The value from any call may be passed in to a later call. - ;; The initial value must be unique for each message/key pair. - ;; NUM is a digit from 0 to 7 inclusive; it is the low 3 bits of the - ;; number of bytes that have previously been processed in this stream. - ;; ENCRYPT? says whether to encrypt (#T) or decrypt (#F). - ;; Returned value is the new value of NUM. (guarantee-bfkey key 'blowfish-cfb64) (guarantee-init-vector init-vector 'blowfish-cfb64) (guarantee-subbytevector input istart iend 'blowfish-cfb64) @@ -123,17 +96,6 @@ USA. (define (blowfish-ofb64 input istart iend output ostart key init-vector num) - ;; Apply Blowfish in Output Feed-Back mode. - ;; (INPUT,ISTART,IEND) is an arbitrary bytevector range. - ;; OUTPUT is a bytevector. - ;; OSTART says where to start writing in OUTPUT. - ;; KEY is a Blowfish key. - ;; INIT-VECTOR is an 8-byte bytevector; it is modified after each call. - ;; The value from any call may be passed in to a later call. - ;; The initial value must be unique for each message/key pair. - ;; NUM is a digit from 0 to 7 inclusive; it is the low 3 bits of the - ;; number of bytes that have previously been processed in this stream. - ;; Returned value is the new value of NUM. (guarantee-bfkey key 'blowfish-ofb64) (guarantee-init-vector init-vector 'blowfish-ofb64) (guarantee-subbytevector input istart iend 'blowfish-ofb64) @@ -221,9 +183,6 @@ USA. (bytevector-fill! output-buffer 0))))) (define (compute-blowfish-init-vector) - ;; This init vector includes a timestamp with a resolution of - ;; milliseconds, plus 20 random bits. This should make it very - ;; difficult to generate two identical vectors. (let ((iv (make-bytevector 8))) (do ((i 0 (fix:+ i 1)) (t (+ (* (+ (* (get-universal-time) 1000) diff --git a/src/blowfish/mit-scheme-blowfish.texi b/src/blowfish/mit-scheme-blowfish.texi new file mode 100644 index 000000000..2fbf3b284 --- /dev/null +++ b/src/blowfish/mit-scheme-blowfish.texi @@ -0,0 +1,723 @@ +\input texinfo @c -*-texinfo-*- +@comment %**start of header +@setfilename mit-scheme-blowfish.info +@include version.texi +@set SCMVERS 9.2.1 +@settitle MIT/GNU Scheme Blowfish Plugin Manual +@comment %**end of header + +@copying +This manual documents MIT/GNU Scheme Blowfish @value{VERSION}. + +Copyright @copyright{} 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, + 2015, 2016, 2017 Matthew Birkholz + +@quotation +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no +Invariant Sections, with 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 quotation +@end copying + +@dircategory Programming Languages +@direntry +* Blowfish: (mit-scheme-blowfish). + Blowfish plugin. +@end direntry + +@titlepage +@title MIT/GNU Scheme Blowfish Plugin Manual +@subtitle a Blowfish block cipher plugin (version @value{VERSION}) +@subtitle for MIT/GNU Scheme version @value{SCMVERS} +@subtitle @value{UPDATED} +@author by Matt Birkholz +@page +@vskip 0pt plus 1filll +@insertcopying +@end titlepage + +@ifnottex +@node Top +@top Blowfish Plugin Manual + +@insertcopying +@end ifnottex + +@menu +* Introduction:: +* Procedures:: +* DES Modes:: +* GNU Free Documentation License:: +@end menu + +@node Introduction +@chapter Introduction + +This plugin is a dynamically loadable wrapper of the Blowfish block +cipher C API as implemented by libssl (OpenSSL). + +The cipher operates on 64 bit (8 byte) blocks of data and uses a +variable size key. Keys with 128 bits (16 bytes) are considered good +for strong encryption. Blowfish can be used in the same modes as DES +and is currently one of the faster block ciphers. It is quite a bit +faster than DES, and much faster than IDEA or RC2. + +The plugin includes a Scheme procedure to feed bytes from a binary +input port to the library, and write the encrypted bytes to a binary +output port. + +@node Procedures +@chapter Procedures + +Blowfish consists of a key setup phase and the actual encryption or +decryption phase. + +@deffn Procedure blowfish-set-key bytes +Generate a Blowfish key from @var{bytes}, which must be 72 bytes or +less in length. For text keys (strings), apply @code{md5} to the +string, and use the digest for @var{bytes}. +@end deffn + +@deffn Procedure blowfish-ecb input output key encyrpt? +Apply Blowfish in Electronic Code Book mode. +@var{Input} is an 8-byte byte vector. +@var{Output} is an 8-byte byte vector. +@var{Key} is a Blowfish key. +@var{Encrypt?} specifies whether to encrypt (when @code{#t}) or decrypt +(when @code{#f}). +@end deffn + +The mode functions below all operate on variable length data. They +all take an initialization vector which needs to be passed along into +the next call of the same function for the same message. The vector +may be initialized with anything, but the recipient needs to know what +it was initialized with, or it won't be able to decrypt. Some +programs and protocols simplify this, like SSH, where the vector is +simply initialized to zero. @code{Blowfish-cbc} operates on data that +is a multiple of 8 bytes long, while @code{blowfish-cfb64} and +@code{blowfish-ofb64} are used to encrypt any number of bytes. The +purpose of the latter two is to simulate stream ciphers, and +therefore, they have a parameter @code{num}, the current offset in the +initialization vector, which should start at zero and be stored +between calls. + +@deffn Procedure blowfish-cbc input output key init encrypt? +Apply Blowfish in Cipher Block Chaining mode. +@var{Input} is a multiple of 8 bytes. +@var{Output} is the same number of bytes as in Input. +@var{Key} is a Blowfish key. +@var{Init} is an 8 byte initialization vector; + it is modified after each call. + The value from any call may be passed in to a later call. +@var{Encrypt?} specifies whether to encrypt (when @code{#t}) or decrypt +(when @code{#f}). +@end deffn + +@deffn Procedure blowfish-cfb64 input istart iend output ostart key init num encrypt? +Apply Blowfish in Cipher Feed-Back mode. +@var{Istart} and @var{Iend} specify a range of bytes in @var{Input}. +@var{Ostart} specifies the first byte to write in @var{Output}. +@var{Key} is a Blowfish key. +@var{Init} is an 8 byte initialization vector; + it is modified after each call. + The value from any call may be passed in to a later call. + The initial value must be unique for each message/key pair. +@var{Num} is an integer from 0 to 7 inclusive, the low 3 bits of the + number of bytes that have previously been processed in this stream. +@var{Encrypt?} specifies whether to encrypt (when @code{#t}) or decrypt +(when @code{#f}). +The returned value is the new value of Num. +@end deffn + +@deffn Procedure blowfish-ofb64 input istart iend output ostart key init num +Apply Blowfish in Output Feed-Back mode. +@var{Istart} and @var{Iend} specify a range of bytes in @var{Input}. +@var{Ostart} specifies the first byte to write in @var{Output}. +@var{Key} is a Blowfish key. +@var{Init} is an 8 byte initialization vector; + it is modified after each call. + The value from any call may be passed in to a later call. + The initial value must be unique for each message/key pair. +@var{Num} is an integer from 0 to 7 inclusive, the low 3 bits of the + number of bytes that have previously been processed in this stream. +The returned value is the new value of Num. +@end deffn + +Two convenience procedures are also provided. + +@deffn Procedure blowfish-encrypt-port input output key init encrypt? +Reads bytes from @var{input}, which should be in blocking mode, until +the end. Feeds the bytes to @code{blowfish-cfb64} and writes the +resulting, encrypted bytes to @var{output}. @var{Key} and +@var{init} are passed to @code{blowfish-cfb64} (which modifies +the latter). +@var{Encrypt?} specifies whether to encrypt (when @code{#t}) or decrypt +(when @code{#f}). +@end deffn + +@deffn Procedure compute-blowfish-init-vector +Returns a new initialization vector that includes a timestamp with a +resolution of milliseconds, plus 20 random bits. This should make it +very likely unique. +@end deffn + +The Blowfish cipher was invented and described by Counterpane (see +@url{http://www.counterpane.com/blowfish.html}). Most of this manual +was adapted from the OpenSSL manual pages. + +@node DES Modes +@chapter DES Modes + +This chapter was written in large parts by Eric Young in his original +documentation for SSLeay, the predecessor of OpenSSL. In turn, he +attributed it to: + +@smallexample +AS 2805.5.2 +Australian Standard +Electronic funds transfer - Requirements for interfaces, +Part 5.2: Modes of operation for an n-bit block cipher algorithm +Appendix A +@end smallexample + +@section Electronic Codebook Mode (ECB) + +64 bits are enciphered at a time. + +The order of the blocks can be rearranged without detection. + +The same plain text block always produces the same cipher text block +(for the same key) making it vulnerable to a dictionary attack. + +An error will only affect one cipher text block. + +@section Cipher Block Chaining Mode (CBC) + +A multiple of 64 bits are enciphered at a time. + +The CBC mode produces the same cipher text whenever the same plain text +is encrypted using the same key and starting variable. + +The chaining operation makes the cipher text blocks dependent on the +current and all preceding plain text blocks and therefore blocks can +not be rearranged. + +The use of different starting variables prevents the same plain text +enciphering to the same cipher text. + +An error will affect the current and the following cipher text blocks. + +@section Cipher Feedback Mode (CFB) + +Any number of bits, j, up to 64, are enciphered at a time. + +The CFB mode produces the same cipher text whenever the same plain text +is encrypted using the same key and starting variable. + +The chaining operation makes the cipher text variables dependent on +the current and all preceding variables and therefore j-bit variables +are chained together and can not be rearranged. + +The use of different starting variables prevents the same plain text +enciphering to the same cipher text. + +The strength of the CFB mode depends on the size of k (maximal if j += k). In my implementation this is always the case. + +Selection of a small value for j will require more cycles through the +encipherment algorithm per unit of plain text and thus cause greater +processing overheads. + +Only multiples of j bits can be enciphered. + +An error will affect the current and the following cipher text +variables. + +@section Output Feedback Mode (OFB) + +Any number of bits, j, up to 64, are enciphered at a time. + +The OFB mode produces the same cipher text whenever the same plain text +enciphered using the same key and starting variable. More over, in +the OFB mode the same key stream is produced when the same key and +start variable are used. Consequently, for security reasons a +specific start variable should be used only once for a given key. + +The absence of chaining makes the OFB more vulnerable to specific +attacks. + +The use of different start variables values prevents the same +plain text enciphering to the same cipher text, by producing different +key streams. + +Selection of a small value for j will require more cycles through the +encipherment algorithm per unit of plain text and thus cause greater +processing overheads. + +Only multiples of j bits can be enciphered. + +OFB mode of operation does not extend cipher text errors in the +resultant plain text output. Every bit error in the cipher text causes +only one bit to be in error in the deciphered plain text. + +OFB mode is not self-synchronizing. If the two operations of +encipherment and decipherment get out of synchronism, the system +needs to be re-initialized. + +Each re-initialization should use a value of the start variable +different from the start variable values used before with the same +key. The reason for this is that an identical bit stream would be +produced each time from the same parameters. This would be +susceptible to a 'known plain text' attack. + +@node GNU Free Documentation License +@appendix GNU Free Documentation License + +@cindex FDL, GNU Free Documentation License +@center Version 1.2, November 2002 + +@display +Copyright @copyright{} 2000,2001,2002 Free Software Foundation, Inc. +51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA + +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. 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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 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 Warrany 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 for under this License. Any other attempt to +copy, modify, sublicense or distribute the Document is void, and will +automatically terminate your rights under this License. However, +parties who have received copies, or rights, from you under this +License will not have their licenses terminated so long as such +parties remain in full compliance. + +@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 +Free Software Foundation. If the Document does not specify a version +number of this License, you may choose any version ever published (not +as a draft) by the Free Software Foundation. +@end enumerate + +@page +@appendixsec 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 1.2 + 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...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. + +@bye -- 2.25.1