MD5(3)

NAME
MD4, MD5, MD4_Init, MD4_Update, MD4_Final, MD5_Init, MD5_Update, MD5_Final - MD4 and MD5 hash functions

SYNOPSIS
libcrypto
#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
MD4 and MD5 are cryptographic hash functions with a 128-bit output.

MD4() and MD5() compute the MD4 and MD5 message digest of the n bytes at d and place it in md, which must have space for MD4_DIGEST_LENGTH == MD5_DIGEST_LENGTH == 16 bytes of output.

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

MD5_Init() initializes a MD5_CTX structure.

MD5_Update() can be called repeatedly with chunks of the message to be hashed (len bytes at data).

MD5_Final() places the message digest in md, which must have space for MD5_DIGEST_LENGTH == 16 bytes of output, and erases the MD5_CTX.

MD4_Init(), MD4_Update(), and MD4_Final() are analogous using an MD4_CTX structure.

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

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

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

SEE ALSO
EVP_DigestInit(3)

STANDARDS
RFC 1320, RFC 1321

HISTORY
MD5(), MD5_Init(), MD5_Update(), and MD5_Final() appeared in SSLeay 0.4 or earlier and have been available since OpenBSD 2.4.

MD4(), MD4_Init(), MD4_Update(), and MD4_Final() first appeared in OpenSSL 0.9.6 and have been available since OpenBSD 2.9.

CAVEATS
Other implementations allow md in MD4() and MD5() to be NULL and return a static array, which is not thread safe.