=pod =head1 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 =head1 SYNOPSIS #include 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 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 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); =head1 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 B bytes at B and place it in B (which must have space for MD2_DIGEST_LENGTH == MD4_DIGEST_LENGTH == MD5_DIGEST_LENGTH == 16 bytes of output). If B 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 B structure. MD2_Update() can be called repeatedly with chunks of the message to be hashed (B bytes at B). MD2_Final() places the message digest in B, which must have space for MD2_DIGEST_LENGTH == 16 bytes of output, and erases the B. MD4_Init(), MD4_Update(), MD4_Final(), MD5_Init(), MD5_Update(), and MD5_Final() are analogous using an B and B structure. Applications should use the higher level functions L etc. instead of calling the hash functions directly. =head1 NOTE MD2, MD4, and MD5 are recommended only for compatibility with existing applications. In new applications, SHA-1 or RIPEMD-160 should be preferred. =head1 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. =head1 CONFORMING TO RFC 1319, RFC 1320, RFC 1321 =head1 SEE ALSO L, L, L =head1 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. =cut