NAME    [Toc]    [Back]

       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

SYNOPSIS    [Toc]    [Back]

        #include <openssl/md2.h>

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

        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);

        #include <openssl/md4.h>

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

        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);

        #include <openssl/md5.h>

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

        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);

DESCRIPTION    [Toc]    [Back]

       MD2, MD4, and MD5 are cryptographic hash functions with a
       128 bit output.

       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    [Toc]    [Back]

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

RETURN VALUES    [Toc]    [Back]

       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() do not return values.

CONFORMING TO    [Toc]    [Back]

       RFC 1319, RFC 1320, RFC 1321

SEE ALSO    [Toc]    [Back]

       sha(3), ripemd(3), EVP_DigestInit(3)

HISTORY    [Toc]    [Back]

       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.


OpenBSD 3.6                 2000-12-14                          2