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MD2(3)                     Library Functions Manual                     MD2(3)

     MD2Init, MD2Update, MD2Final, MD2End, MD2File, MD2Data - calculate the
     RSA Data Security, Inc., "MD2" message digest

     Standard C Library (libc, -lc)

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

     MD2Init(MD2_CTX *context);

     MD2Update(MD2_CTX *context, const unsigned char *data, unsigned int len);

     MD2Final(unsigned char digest[16], MD2_CTX *context);

     char *
     MD2End(MD2_CTX *context, char *buf);

     char *
     MD2File(const char *filename, char *buf);

     char *
     MD2Data(const unsigned char *data, unsigned int len, char *buf);

     The MD2 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

     The MD2 routines should not be used for any security-related purpose.

     The MD2Init(), MD2Update(), and MD2Final() functions are the core
     functions.  Allocate an MD2_CTX, initialize it with MD2Init(), run over
     the data with MD2Update(), and finally extract the result using

     MD2End() is a wrapper for MD2Final() which converts the return value to a
     33-character (including the terminating '\0') ASCII string which
     represents the 128 bits in hexadecimal.

     MD2File() calculates the digest of a file, and uses MD2End() to return
     the result.  If the file cannot be opened, a null pointer is returned.
     MD2Data() calculates the digest of a chunk of data in memory, and uses
     MD2End() to return the result.

     When using MD2End(), MD2File(), or MD2Data(), 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.

     md4(3), md5(3), openssl_MD2(3), openssl_MD4(3), openssl_MD5(3),

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

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

     These functions appeared in NetBSD 1.3.

     The original MD2 routines were developed by RSA Data Security, Inc., and
     published in the above references.  This code is a public domain
     implementation by Andrew Brown.

     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.

NetBSD 10.99                  September 24, 2005                  NetBSD 10.99