- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- CONFORMING TO
- SEE ALSO
- HISTORY

# NAME

MDC2, MDC2_Init, MDC2_Update, MDC2_Final - MDC2 hash function

# SYNOPSIS

     #include <openssl/mdc2.h>

     unsigned char *MDC2(const unsigned char *d, unsigned long n,
                      unsigned char *md);

     int MDC2_Init(MDC2_CTX *c);
     int MDC2_Update(MDC2_CTX *c, const unsigned char *data,
                      unsigned long len);
     int MDC2_Final(unsigned char *md, MDC2_CTX *c);

# DESCRIPTION

MDC2 is a method to construct hash functions with 128 bit output from block ciphers. These functions are an implementation of MDC2 with DES.

`MDC2()` computes the MDC2 message digest of the n bytes at d and places it in md (which must have space for MDC2_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:

`MDC2_Init()` initializes a MDC2_CTX structure.

`MDC2_Update()` can be called repeatedly with chunks of the message to be hashed (len bytes at data).

`MDC2_Final()` places the message digest in md, which must have space for MDC2_DIGEST_LENGTH == 16 bytes of output, and erases the MDC2_CTX.

Applications should use the higher level functions EVP_DigestInit etc. instead of calling the hash functions directly.

# RETURN VALUES

`MDC2()` returns a pointer to the hash value.

MDC2_Init(), `MDC2_Update()` and `MDC2_Final()` return 1 for success, 0 otherwise.

# CONFORMING TO

ISO/IEC 10118-2, with DES

# SEE ALSO

sha, EVP_DigestInit

# HISTORY

MDC2(), MDC2_Init(), `MDC2_Update()` and `MDC2_Final()` are available since SSLeay 0.8.