From 2abdcece17d2d6b98a68ced92bdf17565e8f1471 Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Mon, 28 Sep 2015 19:34:27 +0200 Subject: info: hashing files MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- doc/info/libkeccak.texinfo | 64 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) (limited to 'doc/info/libkeccak.texinfo') diff --git a/doc/info/libkeccak.texinfo b/doc/info/libkeccak.texinfo index 8c511ab..6b238d7 100644 --- a/doc/info/libkeccak.texinfo +++ b/doc/info/libkeccak.texinfo @@ -73,6 +73,7 @@ with support for bit-oriented data. * State of the hashing:: The structure used to keep track of the hashing process. * Hashing messages:: Functions used to hash a message. * Hexadecimal hashes:: Converting between binary and hexadecimal. +* Hashing files:: Functions used to hash entire files. * GNU Affero General Public License:: Copying and sharing libkeccak. * GNU Free Documentation License:: Copying and sharing this manual. @@ -81,7 +82,6 @@ with support for bit-oriented data. * Data type index:: Index of data types. * Function index:: Index of functions. @end menu -@c TODO @detailmenu (`C-c C-u m`) @@ -566,6 +566,68 @@ and have an even length. +@node Hashing files +@chapter Hashing files + +libkeccak provides functions for calculating +hashes of files directly, from a file descriptor. + +The generalised function is named +@code{libkeccak_generalised_sum_fd}. It has +five parameters: +@itemize @bullet{} +@item +The file descriptor. +@item +A pointer to a state variable. Must not be +initalised, lest you will suffer a memory leak. +@item +The specifications for the hashing functions. +@item +The message suffix. +@item +The output buffer for the binary hash. +It must have an allocation size of at least +@code{(spec->output / 8) * sizeof(char)}, +where @code{spec} is the third argument, or +be @code{NULL}. +@end itemize +@code{libkeccak_generalised_sum_fd} returns +zero upon successful completion. On error, +@code{errno} is set to describe the error, +and @code{-1} is returned. + +There are also algorithm specific functions. +@table @code +@item libkeccak_keccaksum_fd +This function is used for Keccak without message +suffix. It is identical to @code{libkeccak_generalised_sum_fd} +sans the fourth parameter (the message suffix.) + +@item libkeccak_sha3sum_fd +This function is used for SHA-3. It is similar +to @code{libkeccak_generalised_sum_fd}, however +it does not have the fourth parameter, and the +third parameter is simple the the output size. +The output buffer must have and allocation size +of at least @code{(output / 8) * sizeof(char)}, +where @code{output} is the third parameter, or +be @code{NULL}. + +@item libkeccak_rawshakesum_fd +This function is used for RawSHAKE, it is +otherwise identical to @code{libkeccak_sha3sum_fd}, +except it as a parameter for the semicapacity +before the output size, that is to say, as its +third parameter. + +@item libkeccak_shakesum_fd +This function is used for SHAKE, it is +otherwise identical to @code{libkeccak_rawshakesum_fd}. +@end table + + + @node GNU Affero General Public License @appendix GNU Affero General Public License @include agpl-3.0.texinfo -- cgit v1.2.3-70-g09d2