Manual Pages for UNIX Operating System command usage for man MD4Init

Extended Library Functions                              md4(3EXT)



NAME
     md4, MD4Init, MD4Update, MD4Final - MD4 digest functions

SYNOPSIS
     cc [ flag ... ] file ... -lmd [ library ... ]
     #include 

     void MD4Init(MD4_CTX *context);


     void MD4Update(MD4_CTX *context, unsigned char *input,
          unsigned int inlen);


     void MD4Final(unsigned char *output, MD4_CTX *context);


DESCRIPTION
     The MD4 functions implement  the  MD4  message-digest  algo-
     rithm.  The  algorithm takes as input a message of arbitrary
     length and produces a "fingerprint" or "message  digest"  as
     output.  The  MD4  message-digest  algorithm is intended for
     digital signature applications  in  which  large  files  are
     "compressed"  in a secure manner before being encrypted with
     a private (secret) key under a public-key cryptosystem  such
     as RSA.

  MD4Init(), MD4Update(), MD4Final()
     The MD4Init(), MD4Update(), and MD4Final()  functions  allow
     an  MD4  digest to be computed over multiple message blocks.
     Between blocks, the state of the MD4 computation is held  in
     an MD4 context structure allocated by the caller. A complete
     digest computation consists of calls to MD4 functions in the
     following order: one call to MD4Init(), one or more calls to
     MD4Update(), and one call to MD4Final().


     The MD4Init() function initializes the MD4 context structure
     pointed to by context.


     The MD4Update() function computes a partial  MD4  digest  on
     the  inlen-byte  message  block  pointed  to  by  input, and
     updates the MD4 context  structure  pointed  to  by  context
     accordingly.


     The MD4Final() function  generates  the  final  MD4  digest,
     using  the  MD4 context structure pointed to by context. The
     MD4 digest is written to output. After a call to MD4Final(),
     the  state of the context structure is undefined. It must be
     reinitialized with MD4Init() before it can be used again.



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Extended Library Functions                              md4(3EXT)



RETURN VALUES
     These functions do not return a value.

SECURITY
     The MD4 digest algorithm is not currently considered crypto-
     graphically secure. It is included in libmd(3LIB) for use by
     legacy protocols and systems only. It should not be used  by
     new systems or protocols.

EXAMPLES
     Example 1 Authenticate a message found in multiple buffers


     The following is a sample function that must authenticate  a
     message that is found in multiple buffers. The calling func-
     tion provides an authentication buffer that will contain the
     result of the MD4 digest.


       #include 
       #include 
       #include 

       int
       AuthenticateMsg(unsigned char *auth_buffer, struct iovec
                       *messageIov, unsigned int num_buffers)
       {
           MD4_CTX ctx;
           unsigned int i;

           MD4Init(&ctx);

           for(i=0; i           {
                MD4Update(&ctx, messageIov->iov_base,
                          messageIov->iov_len);
                messageIov += sizeof(struct iovec);
           }

           MD4Final(auth_buffer, &ctx);

           return 0;
       }


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:







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Extended Library Functions                              md4(3EXT)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     libmd(3LIB)


     RFC 1320









































SunOS 5.11          Last change: 13 Nov 2007                    3