md5(3)                              OpenSSL                             md5(3)



NAME
       MD2, MD4, MD5, MD2_Init, MD2_Update, MD2_Final, MD4_Init, MD4_Update,
       MD4_Final, MD5_Init, MD5_Update, MD5_Final - MD2, MD4, and MD5 hash
       functions

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/md2.h>

        unsigned char *MD2(const unsigned char *d, unsigned long n,
                         unsigned char *md);

        int MD2_Init(MD2_CTX *c);
        int MD2_Update(MD2_CTX *c, const unsigned char *data,
                         unsigned long len);
        int MD2_Final(unsigned char *md, MD2_CTX *c);

        #include <openssl/md4.h>

        unsigned char *MD4(const unsigned char *d, unsigned long n,
                         unsigned char *md);

        int MD4_Init(MD4_CTX *c);
        int MD4_Update(MD4_CTX *c, const void *data,
                         unsigned long len);
        int MD4_Final(unsigned char *md, MD4_CTX *c);

        #include <openssl/md5.h>

        unsigned char *MD5(const unsigned char *d, unsigned long n,
                         unsigned char *md);

        int MD5_Init(MD5_CTX *c);
        int MD5_Update(MD5_CTX *c, const void *data,
                         unsigned long len);
        int MD5_Final(unsigned char *md, MD5_CTX *c);

DESCRIPTION
       MD2, MD4, and MD5 are cryptographic hash functions with a 128 bit out-
       put.

       MD2(), MD4(), and MD5() compute the MD2, MD4, and MD5 message digest of
       the n bytes at d and place it in md (which must have space for
       MD2_DIGEST_LENGTH == MD4_DIGEST_LENGTH == MD5_DIGEST_LENGTH == 16 bytes
       of output). If md is NULL, the digest is placed in a static array.

       The following functions may be used if the message is not completely
       stored in memory:

       MD2_Init() initializes a MD2_CTX structure.

       MD2_Update() can be called repeatedly with chunks of the message to be
       hashed (len bytes at data).

       MD2_Final() places the message digest in md, which must have space for
       MD2_DIGEST_LENGTH == 16 bytes of output, and erases the MD2_CTX.

       MD4_Init(), MD4_Update(), MD4_Final(), MD5_Init(), MD5_Update(), and
       MD5_Final() are analogous using an MD4_CTX and MD5_CTX structure.

       Applications should use the higher level functions EVP_DigestInit(3)
       etc. instead of calling the hash functions directly.

NOTE
       MD2, MD4, and MD5 are recommended only for compatibility with existing
       applications. In new applications, SHA-1 or RIPEMD-160 should be pre-
       ferred.

RETURN VALUES
       MD2(), MD4(), and MD5() return pointers to the hash value.

       MD2_Init(), MD2_Update(), MD2_Final(), MD4_Init(), MD4_Update(),
       MD4_Final(), MD5_Init(), MD5_Update(), and MD5_Final() return 1 for
       success, 0 otherwise.

CONFORMING TO
       RFC 1319, RFC 1320, RFC 1321

SEE ALSO
       openssl_sha(3), openssl_ripemd(3), EVP_DigestInit(3)

HISTORY
       MD2(), MD2_Init(), MD2_Update() MD2_Final(), MD5(), MD5_Init(),
       MD5_Update() and MD5_Final() are available in all versions of SSLeay
       and OpenSSL.

       MD4(), MD4_Init(), and MD4_Update() are available in OpenSSL 0.9.6 and
       above.



0.9.9-dev                         2007-03-06                            md5(3)
