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

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

       EVP_DigestInit(3)

COPYRIGHT

       Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use this file except in compliance with
       the License.  You can obtain a copy in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.