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 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

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.

2009-07-19 | 1.0.2k