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hmac.c

/* crypto/hmac/hmac.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cryptlib.h"
#include <openssl/hmac.h>

#ifndef OPENSSL_FIPS

void HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,
              const EVP_MD *md, ENGINE *impl)
      {
      int i,j,reset=0;
      unsigned char pad[HMAC_MAX_MD_CBLOCK];

      if (md != NULL)
            {
            reset=1;
            ctx->md=md;
            }
      else
            md=ctx->md;

      if (key != NULL)
            {
            reset=1;
            j=EVP_MD_block_size(md);
            OPENSSL_assert(j <= (int)sizeof(ctx->key));
            if (j < len)
                  {
                  EVP_DigestInit_ex(&ctx->md_ctx,md, impl);
                  EVP_DigestUpdate(&ctx->md_ctx,key,len);
                  EVP_DigestFinal_ex(&(ctx->md_ctx),ctx->key,
                        &ctx->key_length);
                  }
            else
                  {
                  OPENSSL_assert(len>=0 && len<=(int)sizeof(ctx->key));
                  memcpy(ctx->key,key,len);
                  ctx->key_length=len;
                  }
            if(ctx->key_length != HMAC_MAX_MD_CBLOCK)
                  memset(&ctx->key[ctx->key_length], 0,
                        HMAC_MAX_MD_CBLOCK - ctx->key_length);
            }

      if (reset)  
            {
            for (i=0; i<HMAC_MAX_MD_CBLOCK; i++)
                  pad[i]=0x36^ctx->key[i];
            EVP_DigestInit_ex(&ctx->i_ctx,md, impl);
            EVP_DigestUpdate(&ctx->i_ctx,pad,EVP_MD_block_size(md));

            for (i=0; i<HMAC_MAX_MD_CBLOCK; i++)
                  pad[i]=0x5c^ctx->key[i];
            EVP_DigestInit_ex(&ctx->o_ctx,md, impl);
            EVP_DigestUpdate(&ctx->o_ctx,pad,EVP_MD_block_size(md));
            }
      EVP_MD_CTX_copy_ex(&ctx->md_ctx,&ctx->i_ctx);
      }

void HMAC_Init(HMAC_CTX *ctx, const void *key, int len,
             const EVP_MD *md)
      {
      if(key && md)
          HMAC_CTX_init(ctx);
      HMAC_Init_ex(ctx,key,len,md, NULL);
      }

void HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)
      {
      EVP_DigestUpdate(&ctx->md_ctx,data,len);
      }

void HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
      {
      int j;
      unsigned int i;
      unsigned char buf[EVP_MAX_MD_SIZE];

      j=EVP_MD_block_size(ctx->md);

      EVP_DigestFinal_ex(&ctx->md_ctx,buf,&i);
      EVP_MD_CTX_copy_ex(&ctx->md_ctx,&ctx->o_ctx);
      EVP_DigestUpdate(&ctx->md_ctx,buf,i);
      EVP_DigestFinal_ex(&ctx->md_ctx,md,len);
      }

void HMAC_CTX_init(HMAC_CTX *ctx)
      {
      EVP_MD_CTX_init(&ctx->i_ctx);
      EVP_MD_CTX_init(&ctx->o_ctx);
      EVP_MD_CTX_init(&ctx->md_ctx);
      }

void HMAC_CTX_cleanup(HMAC_CTX *ctx)
      {
      EVP_MD_CTX_cleanup(&ctx->i_ctx);
      EVP_MD_CTX_cleanup(&ctx->o_ctx);
      EVP_MD_CTX_cleanup(&ctx->md_ctx);
      memset(ctx,0,sizeof *ctx);
      }

unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,
                const unsigned char *d, size_t n, unsigned char *md,
                unsigned int *md_len)
      {
      HMAC_CTX c;
      static unsigned char m[EVP_MAX_MD_SIZE];

      if (md == NULL) md=m;
      HMAC_CTX_init(&c);
      HMAC_Init(&c,key,key_len,evp_md);
      HMAC_Update(&c,d,n);
      HMAC_Final(&c,md,md_len);
      HMAC_CTX_cleanup(&c);
      return(md);
      }

void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)
      {
      EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);
      EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);
      EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);
      }

#endif

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