.\"	$NetBSD: openssl_md5.3,v 1.8 2003/07/24 14:16:51 itojun Exp $
.\"
.\" Automatically generated by Pod::Man version 1.02
.\" Thu Jul 24 13:08:07 2003
.\"
.\" Standard preamble:
.\" ======================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Ip \" List item
.br
.ie \\n(.$>=3 .ne \\$3
.el .ne 3
.IP "\\$1" \\$2
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R

.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  | will give a
.\" real vertical bar.  \*(C+ will give a nicer C++.  Capital omega is used
.\" to do unbreakable dashes and therefore won't be available.  \*(C` and
.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
.tr \(*W-|\(bv\*(Tr
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` `
.    ds C' '
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
'br\}
.\"
.\" If the F register is turned on, we'll generate index entries on stderr
.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
.\" index entries marked with X<> in POD.  Of course, you'll have to process
.\" the output yourself in some meaningful fashion.
.if \nF \{\
.    de IX
.    tm Index:\\$1\t\\n%\t"\\$2"
.    .
.    nr % 0
.    rr F
.\}
.\"
.\" For nroff, turn off justification.  Always turn off hyphenation; it
.\" makes way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.bd B 3
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ======================================================================
.\"
.IX Title "md5 3"
.TH md5 3 "0.9.7b" "2000-08-14" "OpenSSL"
.UC
.SH "NAME"
\&\s-1MD2\s0, \s-1MD4\s0, \s-1MD5\s0, MD2_Init, MD2_Update, MD2_Final, MD4_Init, MD4_Update,
MD4_Final, MD5_Init, MD5_Update, MD5_Final \- \s-1MD2\s0, \s-1MD4\s0, and \s-1MD5\s0 hash functions
.SH "LIBRARY"
libcrypto, -lcrypto
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/md2.h>
.Ve
.Vb 2
\& unsigned char *MD2(const unsigned char *d, unsigned long n,
\&                  unsigned char *md);
.Ve
.Vb 4
\& void MD2_Init(MD2_CTX *c);
\& void MD2_Update(MD2_CTX *c, const unsigned char *data,
\&                  unsigned long len);
\& void MD2_Final(unsigned char *md, MD2_CTX *c);
.Ve
.Vb 1
\& #include <openssl/md4.h>
.Ve
.Vb 2
\& unsigned char *MD4(const unsigned char *d, unsigned long n,
\&                  unsigned char *md);
.Ve
.Vb 4
\& void MD4_Init(MD4_CTX *c);
\& void MD4_Update(MD4_CTX *c, const void *data,
\&                  unsigned long len);
\& void MD4_Final(unsigned char *md, MD4_CTX *c);
.Ve
.Vb 1
\& #include <openssl/md5.h>
.Ve
.Vb 2
\& unsigned char *MD5(const unsigned char *d, unsigned long n,
\&                  unsigned char *md);
.Ve
.Vb 4
\& void MD5_Init(MD5_CTX *c);
\& void MD5_Update(MD5_CTX *c, const void *data,
\&                  unsigned long len);
\& void MD5_Final(unsigned char *md, MD5_CTX *c);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\s-1MD2\s0, \s-1MD4\s0, and \s-1MD5\s0 are cryptographic hash functions with a 128 bit output.
.PP
\&\fIMD2()\fR, \fIMD4()\fR, and \fIMD5()\fR compute the \s-1MD2\s0, \s-1MD4\s0, and \s-1MD5\s0 message digest
of the \fBn\fR bytes at \fBd\fR and place it in \fBmd\fR (which must have space
for \s-1MD2_DIGEST_LENGTH\s0 == \s-1MD4_DIGEST_LENGTH\s0 == \s-1MD5_DIGEST_LENGTH\s0 == 16
bytes of output). If \fBmd\fR is \s-1NULL\s0, the digest is placed in a static
array.
.PP
The following functions may be used if the message is not completely
stored in memory:
.PP
\&\fIMD2_Init()\fR initializes a \fB\s-1MD2_CTX\s0\fR structure.
.PP
\&\fIMD2_Update()\fR can be called repeatedly with chunks of the message to
be hashed (\fBlen\fR bytes at \fBdata\fR).
.PP
\&\fIMD2_Final()\fR places the message digest in \fBmd\fR, which must have space
for \s-1MD2_DIGEST_LENGTH\s0 == 16 bytes of output, and erases the \fB\s-1MD2_CTX\s0\fR.
.PP
\&\fIMD4_Init()\fR, \fIMD4_Update()\fR, \fIMD4_Final()\fR, \fIMD5_Init()\fR, \fIMD5_Update()\fR, and
\&\fIMD5_Final()\fR are analogous using an \fB\s-1MD4_CTX\s0\fR and \fB\s-1MD5_CTX\s0\fR structure.
.PP
Applications should use the higher level functions
EVP_DigestInit(3)
etc. instead of calling the hash functions directly.
.SH "NOTE"
.IX Header "NOTE"
\&\s-1MD2\s0, \s-1MD4\s0, and \s-1MD5\s0 are recommended only for compatibility with existing
applications. In new applications, \s-1SHA-1\s0 or \s-1RIPEMD-160\s0 should be
preferred.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIMD2()\fR, \fIMD4()\fR, and \fIMD5()\fR return pointers to the hash value. 
.PP
\&\fIMD2_Init()\fR, \fIMD2_Update()\fR, \fIMD2_Final()\fR, \fIMD4_Init()\fR, \fIMD4_Update()\fR,
\&\fIMD4_Final()\fR, \fIMD5_Init()\fR, \fIMD5_Update()\fR, and \fIMD5_Final()\fR do not return
values.
.SH "CONFORMING TO"
.IX Header "CONFORMING TO"
\&\s-1RFC\s0 1319, \s-1RFC\s0 1320, \s-1RFC\s0 1321
.SH "SEE ALSO"
.IX Header "SEE ALSO"
openssl_sha(3), openssl_ripemd(3), EVP_DigestInit(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fIMD2()\fR, \fIMD2_Init()\fR, \fIMD2_Update()\fR \fIMD2_Final()\fR, \fIMD5()\fR, \fIMD5_Init()\fR,
\&\fIMD5_Update()\fR and \fIMD5_Final()\fR are available in all versions of SSLeay
and OpenSSL.
.PP
\&\fIMD4()\fR, \fIMD4_Init()\fR, and \fIMD4_Update()\fR are available in OpenSSL 0.9.6 and
above.