213 lines
5.8 KiB
Groff
213 lines
5.8 KiB
Groff
.\" $NetBSD: sha1.3,v 1.1 1999/02/04 05:08:58 explorer Exp $
|
|
.\" $OpenBSD: sha1.3,v 1.9 1998/03/07 22:18:12 millert Exp $
|
|
.\"
|
|
.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by Todd C. Miller.
|
|
.\" 4. The name of the author may not be used to endorse or promote products
|
|
.\" derived from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
|
.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
|
|
.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
|
|
.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
|
.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
|
.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
|
|
.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
|
.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
|
.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" See http://csrc.nist.gov/fips/fip180-1.txt for the detailed standard
|
|
.\"
|
|
.Dd July 10, 1997
|
|
.Dt SHA1 3
|
|
.Sh NAME
|
|
.Nm SHA1Init ,
|
|
.Nm SHA1Update ,
|
|
.Nm SHA1Final ,
|
|
.Nm SHA1Transform ,
|
|
.Nm SHA1End ,
|
|
.Nm SHA1File ,
|
|
.Nm SHA1Data
|
|
.Nd calculate the NIST Secure Hash Algorithm
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <sha1.h>
|
|
.Ft void
|
|
.Fn SHA1Init "SHA1_CTX *context"
|
|
.Ft void
|
|
.Fn SHA1Update "SHA1_CTX *context" "const u_char *data" "u_int len"
|
|
.Ft void
|
|
.Fn SHA1Final "u_char digest[20]" "SHA1_CTX *context"
|
|
.Ft void
|
|
.Fn SHA1Transform "u_int32_t state[5]" "u_char buffer[64]"
|
|
.Ft "char *"
|
|
.Fn SHA1End "SHA1_CTX *context" "char *buf"
|
|
.Ft "char *"
|
|
.Fn SHA1File "char *filename" "char *buf"
|
|
.Ft "char *"
|
|
.Fn SHA1Data "u_char *data" "u_int len" "char *buf"
|
|
.Sh DESCRIPTION
|
|
The SHA1 functions implement the NIST Secure Hash Algorithm (SHA-1),
|
|
FIPS PUB 180-1. SHA-1 is used to generate a condensed representation
|
|
of a message called a message digest. The algorithm takes a
|
|
message less than 2^64 bits as input and produces a 160-bit digest
|
|
suitable for use as a digital signature.
|
|
.Pp
|
|
The SHA1 functions are considered to be more secure than the
|
|
.Xr md4 3
|
|
and
|
|
.Xr md5 3
|
|
functions with which they share a similar interface.
|
|
.Pp
|
|
The
|
|
.Fn SHA1Init
|
|
function initializes a SHA1_CTX
|
|
.Ar context
|
|
for use with
|
|
.Fn SHA1Update ,
|
|
and
|
|
.Fn SHA1Final .
|
|
The
|
|
.Fn SHA1Update
|
|
function adds
|
|
.Ar data
|
|
of length
|
|
.Ar len
|
|
to the SHA1_CTX specified by
|
|
.Ar context.
|
|
.Fn SHA1Final
|
|
is called when all data has been added via
|
|
.Fn SHA1Update
|
|
and stores a message digest in the
|
|
.Ar digest
|
|
parameter.
|
|
When a null pointer is passed to
|
|
.Fn SHA1Final
|
|
as first argument only the final padding will be applied and the
|
|
current context can still be used with
|
|
.Fn SHA1Update .
|
|
.Pp
|
|
The
|
|
.Fn SHA1Transform
|
|
function is used by
|
|
.Fn SHA1Update
|
|
to hash 512-bit blocks and forms the core of the algorithm.
|
|
Most programs should use the interface provided by
|
|
.Fn SHA1Init ,
|
|
.Fn SHA1Update
|
|
and
|
|
.Fn SHA1Final
|
|
instead of calling
|
|
.Fn SHA1Transform
|
|
directly.
|
|
.Pp
|
|
The
|
|
.Fn SHA1End
|
|
function is a front end for
|
|
.Fn SHA1Final
|
|
which converts the digest into an
|
|
.Tn ASCII
|
|
representation of the 160 bit digest in hexadecimal.
|
|
.Pp
|
|
The
|
|
.Fn SHA1File
|
|
function calculates the digest for a file and returns the result via
|
|
.Fn SHA1End .
|
|
If
|
|
.Fn SHA1File
|
|
is unable to open the file a NULL pointer is returned.
|
|
.Pp
|
|
The
|
|
.Fn SHA1Data
|
|
function
|
|
calculates the digest of an arbitrary string and returns the result via
|
|
.Fn SHA1End .
|
|
.Pp
|
|
For each of the
|
|
.Fn SHA1End ,
|
|
.Fn SHA1File ,
|
|
and
|
|
.Fn SHA1Data
|
|
functions the
|
|
.Ar buf
|
|
parameter should either be a string of at least 41 characters in
|
|
size or a NULL pointer. In the latter case, space will be dynamically
|
|
allocated via
|
|
.Xr malloc 3
|
|
and should be freed using
|
|
.Xr free 3
|
|
when it is no longer needed.
|
|
.Sh EXAMPLES
|
|
The follow code fragment will calculate the digest for
|
|
the string "abc" which is ``0xa9993e36476816aba3e25717850c26c9cd0d89d''.
|
|
.Bd -literal -offset indent
|
|
SHA1_CTX sha;
|
|
u_char results[20];
|
|
char *buf;
|
|
int n;
|
|
|
|
buf = "abc";
|
|
n = strlen(buf);
|
|
SHA1Init(&sha);
|
|
SHA1Update(&sha, (u_char *)buf, n);
|
|
SHA1Final(results, &sha);
|
|
|
|
/* Print the digest as one long hex value */
|
|
printf("0x");
|
|
for (n = 0; n < 20; n++)
|
|
printf("%x", results[n]);
|
|
putchar('\\n');
|
|
.Ed
|
|
.Pp
|
|
Alternately, the helper functions could be used in the following way:
|
|
.Bd -literal -offset indent
|
|
SHA1_CTX sha;
|
|
u_char output[41];
|
|
char *buf = "abc";
|
|
|
|
printf("0x%s", SHA1Data(buf, strlen(buf), output));
|
|
.Ed
|
|
.Sh CAVEATS
|
|
This implementation of SHA-1 has not been validated by NIST
|
|
and as such is not in official compliance with the standard.
|
|
.Pp
|
|
If a message digest is to be copied to a multi-byte type (ie:
|
|
an array of five 32-bit integers) it will be necessary to
|
|
perform byte swapping on little endian machines such as the i386, alpha,
|
|
and vax.
|
|
.Sh AUTHOR
|
|
This implementation of SHA-1 was written by Steve Reid.
|
|
.br
|
|
The
|
|
.Fn SHA1End ,
|
|
.Fn SHA1File ,
|
|
and
|
|
.Fn SHA1Data
|
|
helper functions are derived from code written by Poul-Henning Kamp.
|
|
.Sh SEE ALSO
|
|
.Xr sha1 1 ,
|
|
.Xr md4 3 ,
|
|
.Xr md5 3
|
|
.Pp
|
|
.Rs
|
|
.%A J. Burrows
|
|
.%T The Secure Hash Standard
|
|
.%O FIPS PUB 180-1
|
|
.Re
|
|
.Sh HISTORY
|
|
The SHA-1 functions appeared in
|
|
.Ox 2.0 .
|