HP OpenVMS Systems Documentation

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HP Open Source Security for OpenVMS Volume 2: HP SSL for OpenVMS > CRYPTO Application Programming Interface (API) Reference

MDC2

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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);
void MDC2_Init(MDC2_CTX *c);
void MDC2_Update(MDC2_CTX *c, const unsigned char *data, unsigned long len);
void 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(3) 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() do not return values.

CONFORMING TO

ISO/IEC 10118-2, with DES

SEE ALSO

sha(3), EVP_DigestInit(3)

HISTORY

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