md5transform(9) [freebsd man page]

MD5(9)							   BSD Kernel Developer's Manual						    MD5(9)

NAME

     MD5, MD5Init, MD5Transform -- message digest routines

SYNOPSIS

     #include <sys/types.h>
     #include <sys/md5.h>

     void
     MD5Init(MD5_CTX *buf);

     void
     MD5Transform(uint32_t buf[4], const unsigned char block[64]);

DESCRIPTION

     The MD5 module implements the RSA Data Security, Inc. MD5 Message-Digest Algorithm (MD5).	It produces 128-bit MD5 Digest of data.

     MD5Init	      must be called just before MD5Transform() will be used to produce a digest.  The buf argument is the storage for the digest
		      being produced on subsequent calls to the MD5Transform() routine.

     MD5Transform     is the core of the MD5 algorithm, this alters an existing MD5 hash kept in buf to reflect the addition of 64 characters of
		      new data passed in block argument.

COPYRIGHTS

     The code for MD5 transform was taken from Colin Plumb's implementation, which has been placed in the public domain.  The MD5 cryptographic
     checksum was devised by Ronald Rivest, and is documented in RFC 1321, "The MD5 Message Digest Algorithm".

BSD
								  April 17, 1996							       BSD

MD5(3)							   BSD Library Functions Manual 						    MD5(3)

NAME

     MD5Init, MD5Update, MD5Final, MD5End, MD5File, MD5Data -- calculate the RSA Data Security, Inc., ``MD5'' message digest

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/types.h>
     #include <md5.h>

     void
     MD5Init(MD5_CTX *context);

     void
     MD5Update(MD5_CTX *context, const unsigned char *data, unsigned int len);

     void
     MD5Final(unsigned char digest[16], MD5_CTX *context);

     char *
     MD5End(MD5_CTX *context, char *buf);

     char *
     MD5File(const char *filename, char *buf);

     char *
     MD5Data(const unsigned char *data, unsigned int len, char *buf);

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
     ``fingerprint'' of the input-data, which doesn't disclose the actual input.

     MD2 is the slowest, MD4 is the fastest and MD5 is somewhere in the middle.  MD2 can only be used for Privacy-Enhanced Mail.  MD4 has been
     criticized for being too weak, so MD5 was developed in response as ``MD4 with safety-belts''.  When in doubt, use MD5.

     The MD5Init(), MD5Update(), and MD5Final() functions are the core functions.  Allocate an MD5_CTX, initialize it with MD5Init(), run over the
     data with MD5Update(), and finally extract the result using MD5Final().

     MD5End() is a wrapper for MD5Final() which converts the return value to a 33-character (including the terminating '') ASCII string which
     represents the 128 bits in hexadecimal.

     MD5File() calculates the digest of a file, and uses MD5End() to return the result.  If the file cannot be opened, a null pointer is returned.
     MD5Data() calculates the digest of a chunk of data in memory, and uses MD5End() to return the result.

     When using MD5End(), MD5File(), or MD5Data(), the buf argument can be a null pointer, in which case the returned string is allocated with
     malloc(3) and subsequently must be explicitly deallocated using free(3) after use.  If the buf argument is non-null it must point to at least
     33 characters of buffer space.

SEE ALSO

     md2(3), md4(3), md5(3)

     B. Kaliski, The MD2 Message-Digest Algorithm, RFC 1319.

     R. Rivest, The MD4 Message-Digest Algorithm, RFC 1186.

     R. Rivest, The MD5 Message-Digest Algorithm, RFC 1321.

     RSA Laboratories, Frequently Asked Questions About today's Cryptography.

HISTORY

     These functions appeared in NetBSD 1.3.

AUTHORS

     The original MD5 routines were developed by RSA Data Security, Inc., and published in the above references.  This code is derived directly
     from these implementations by Poul-Henning Kamp <phk@login.dkuug.dk>

     Phk ristede runen.

BUGS

     No method is known to exist which finds two files having the same hash value, nor to find a file with a specific hash value.  There is on the
     other hand no guarantee that such a method doesn't exist.

COPYRIGHT

     Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All rights reserved.

     License to copy and use this software is granted provided that it is identified as the "RSA Data Security, Inc. MD5 Message-Digest Algorithm"
     in all material mentioning or referencing this software or this function.

     License is also granted to make and use derivative works provided that such works are identified as "derived from the RSA Data Security, Inc.
     MD5 Message-Digest Algorithm" in all material mentioning or referencing the derived work.

     RSA Data Security, Inc. makes no representations concerning either the merchantability of this software or the suitability of this software
     for any particular purpose. It is provided "as is" without express or implied warranty of any kind.

     These notices must be retained in any copies of any part of this documentation and/or software.

BSD
								   June 13, 2003							       BSD