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  • /* rsa-compat.c
     *
     * The RSA publickey algorithm, RSAREF compatible interface.
     */
    
    /* nettle, low-level cryptographics library
     *
     * Copyright (C) 2001 Niels Mller
     *  
     * The nettle library is free software; you can redistribute it and/or modify
     * it under the terms of the GNU Lesser General Public License as published by
     * the Free Software Foundation; either version 2.1 of the License, or (at your
     * option) any later version.
     * 
     * The nettle library is distributed in the hope that it will be useful, but
     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
     * License for more details.
     * 
     * You should have received a copy of the GNU Lesser General Public License
     * along with the nettle library; see the file COPYING.LIB.  If not, write to
     * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
     * MA 02111-1307, USA.
     */
    
    #include "rsa-compat.h"
    
    
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    #include "bignum.h"
    
    #include "md5.h"
    
    int
    R_SignInit(R_SIGNATURE_CTX *ctx,
               int digestAlgorithm)
    {
      if (digestAlgorithm != DA_MD5)
        return RE_DIGEST_ALGORITHM;
    
      md5_init(&ctx->hash);
    
      return 0;
    }
    
    int
    R_SignUpdate(R_SIGNATURE_CTX *ctx,
                 const uint8_t *data,
                 /* Length is an unsigned char according to rsaref.txt,
                  * but that must be a typo. */
                 unsigned length)
    {
      md5_update(&ctx->hash, length, data);
    
      return RE_SUCCESS;
    }
    
    int
    R_SignFinal(R_SIGNATURE_CTX *ctx,
                uint8_t *signature,
                unsigned *length,
                R_RSA_PRIVATE_KEY *key)
    {
      struct rsa_private_key k;
      int res;
      
      nettle_mpz_init_set_str_256(k.pub.n,
                                  MAX_RSA_MODULUS_LEN, key->modulus);
      nettle_mpz_init_set_str_256(k.pub.e,
                                  MAX_RSA_MODULUS_LEN, key->publicExponent);
      nettle_mpz_init_set_str_256(k.p,
                                  MAX_RSA_MODULUS_LEN, key->prime[0]);
      nettle_mpz_init_set_str_256(k.q,
                                  MAX_RSA_MODULUS_LEN, key->prime[1]);
      nettle_mpz_init_set_str_256(k.a,
                                  MAX_RSA_MODULUS_LEN, key->primeExponent[0]);
      nettle_mpz_init_set_str_256(k.b,
                                  MAX_RSA_MODULUS_LEN, key->primeExponent[1]);
      nettle_mpz_init_set_str_256(k.c,
                                  MAX_RSA_MODULUS_LEN, key->coefficient);
    
    
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      if (rsa_init_private_key(&k) && (k.pub.size <= MAX_RSA_MODULUS_LEN))
    
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          *length = k.pub.size;
          rsa_md5_sign(&k, &ctx->hash, signature);
    
          res = RE_SUCCESS;
        }
      else
        res = RE_PRIVATE_KEY;
      
      mpz_clear(k.pub.n);
      mpz_clear(k.pub.e);
      mpz_clear(k.p);
      mpz_clear(k.q);
      mpz_clear(k.a);
      mpz_clear(k.b);
      mpz_clear(k.c);
    
      return res;
    }
    
    int
    R_VerifyInit(R_SIGNATURE_CTX *ctx,
                 int digestAlgorithm)
    {
      return R_SignInit(ctx, digestAlgorithm);
    }
    
    int
    R_VerifyUpdate(R_SIGNATURE_CTX *ctx,
                   const uint8_t *data,
                   /* Length is an unsigned char according to rsaref.txt,
                    * but that must be a typo. */
                   unsigned length)
    {
      return R_SignUpdate(ctx, data, length);
    }
    
    int
    R_VerifyFinal(R_SIGNATURE_CTX *ctx,
                  uint8_t *signature,
                  unsigned length,
                  R_RSA_PUBLIC_KEY *key)
    {
      struct rsa_public_key k;
      int res;
    
      nettle_mpz_init_set_str_256(k.n,
                                  MAX_RSA_MODULUS_LEN, key->modulus);
      nettle_mpz_init_set_str_256(k.e,
    
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                                  MAX_RSA_MODULUS_LEN, key->exponent);
    
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      if (rsa_init_public_key(&k) && (k.size == length))
    
        res = rsa_md5_verify(&k, &ctx->hash, signature)
          ? RE_SUCCESS : RE_SIGNATURE;
      else
        res = RE_PUBLIC_KEY;
    
      mpz_clear(k.n);
      mpz_clear(k.e);
    
      return res;
    }