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

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 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

       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

       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

       sha(3), 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.