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Diffstat (limited to 'static/openbsd/man3/MD5Init.3')
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diff --git a/static/openbsd/man3/MD5Init.3 b/static/openbsd/man3/MD5Init.3 new file mode 100644 index 00000000..5bb3c697 --- /dev/null +++ b/static/openbsd/man3/MD5Init.3 @@ -0,0 +1,213 @@ +.\" +.\" Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.\" If we meet some day, and you think this stuff is worth it, you +.\" can buy me a beer in return. Poul-Henning Kamp +.\" +.\" $OpenBSD: MD5Init.3,v 1.4 2025/06/13 18:34:00 schwarze Exp $ +.\" +.Dd $Mdocdate: June 13 2025 $ +.Dt MD5INIT 3 +.Os +.Sh NAME +.Nm MD5Init , +.Nm MD5Update , +.Nm MD5Pad , +.Nm MD5Final , +.Nm MD5Transform , +.Nm MD5End , +.Nm MD5File , +.Nm MD5FileChunk , +.Nm MD5Data +.Nd calculate MD5 message digest +.Sh SYNOPSIS +.In sys/types.h +.In md5.h +.Ft void +.Fn MD5Init "MD5_CTX *context" +.Ft void +.Fn MD5Update "MD5_CTX *context" "const u_int8_t *data" "size_t len" +.Ft void +.Fn MD5Pad "MD5_CTX *context" +.Ft void +.Fn MD5Final "u_int8_t digest[MD5_DIGEST_LENGTH]" "MD5_CTX *context" +.Ft void +.Fn MD5Transform "u_int32_t state[4]" "u_int8_t block[MD5_BLOCK_LENGTH]" +.Ft char * +.Fn MD5End "MD5_CTX *context" "char *buf" +.Ft char * +.Fn MD5File "const char *filename" "char *buf" +.Ft char * +.Fn MD5FileChunk "const char *filename" "char *buf" "off_t offset" "off_t length" +.Ft char * +.Fn MD5Data "const u_int8_t *data" "size_t len" "char *buf" +.Sh DESCRIPTION +The MD5 functions calculate a 128-bit cryptographic checksum (digest) +for any number of input bytes. +A cryptographic checksum is a one-way +hash-function, that is, you cannot find (except by exhaustive search) +the input corresponding to a particular output. +This net result is a +.Dq fingerprint +of the input-data, which doesn't disclose the actual input. +.Pp +MD5 has been broken; it should only be used where necessary for +backward compatibility. +The attack on MD5 is in the nature of finding +.Dq collisions +\(em that is, multiple inputs which hash to the same value. +It is still unlikely for an attacker to be able to determine the exact +original input given a hash value. +.Pp +The +.Fn MD5Init , +.Fn MD5Update , +and +.Fn MD5Final +functions are the core functions. +Allocate an +.Vt MD5_CTX , +initialize it with +.Fn MD5Init , +run over the data with +.Fn MD5Update , +and finally extract the result using +.Fn MD5Final . +.Pp +The +.Fn MD5Pad +function can be used to apply padding to the message digest as in +.Fn MD5Final , +but the current context can still be used with +.Fn MD5Update . +.Pp +The +.Fn MD5Transform +function is used by +.Fn MD5Update +to hash 512-bit blocks and forms the core of the algorithm. +Most programs should use the interface provided by +.Fn MD5Init , +.Fn MD5Update +and +.Fn MD5Final +instead of calling +.Fn MD5Transform +directly. +.Pp +.Fn MD5End +is a wrapper for +.Fn MD5Final +which converts the return value to an MD5_DIGEST_STRING_LENGTH-character +(including the terminating '\e0') +ASCII string which represents the 128 bits in hexadecimal. +.Pp +.Fn MD5File +calculates the digest of a file, and uses +.Fn MD5End +to return the result. +If the file cannot be opened, a null pointer is returned. +.Pp +.Fn MD5FileChunk +behaves like +.Fn MD5File +but calculates the digest only for that portion of the file starting at +.Fa offset +and continuing for +.Fa length +bytes or until end of file is reached, whichever comes first. +A zero +.Fa length +can be specified to read until end of file. +A negative +.Fa length +or +.Fa offset +will be ignored. +.Fn MD5Data +calculates the digest of a chunk of data in memory, and uses +.Fn MD5End +to return the result. +.Pp +When using +.Fn MD5End , +.Fn MD5File , +.Fn MD5FileChunk , +or +.Fn MD5Data , +the +.Ar buf +argument can be a null pointer, in which case the returned string +is allocated with +.Xr malloc 3 +and subsequently must be explicitly deallocated using +.Xr free 3 +after use. +If the +.Ar buf +argument is non-null, it must point to at least MD5_DIGEST_STRING_LENGTH +characters of buffer space. +.Sh SEE ALSO +.Xr cksum 1 , +.Xr md5 1 , +.Xr RMD160Init 3 , +.Xr SHA1Init 3 , +.Xr SHA256Init 3 +.Rs +.%A H. Dobbertin +.%D 1995 +.%J CryptoBytes +.%N 1(3):5 +.%T Alf Swindles Ann +.Re +.Rs +.%A MJ. B. Robshaw +.%D November 12, 1996 +.%J RSA Laboratories Bulletin +.%N 4 +.%T On Recent Results for MD4 and MD5 +.Re +.Rs +.%A Hans Dobbertin +.%T Cryptanalysis of MD5 Compress +.Re +.Sh STANDARDS +.Rs +.%A R. Rivest +.%D April 1992 +.%R RFC 1321 +.%T The MD5 Message Digest Algorithm +.Re +.Sh HISTORY +These functions appeared in +.Ox 2.0 . +.Sh AUTHORS +.An -nosplit +The original MD5 routines were developed by +RSA Data Security, Inc., and published in the above references. +This code is derived from a public domain implementation written by +.An Colin Plumb . +.Pp +The +.Fn MD5End , +.Fn MD5File , +.Fn MD5FileChunk , +and +.Fn MD5Data +helper functions are derived from code written by +.An Poul-Henning Kamp . +.Sh BUGS +Collisions have been found for the full version of MD5. +The use of the SHA2 functions is recommended instead. |