der2rsa.c

/* der2rsa.c
 *
 * Decoding of keys in PKCS#1 format.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2005 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.
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#if WITH_PUBLIC_KEY

#include "rsa.h"

#include "bignum.h"
#include "asn1.h"

#define GET(i, x, l)					\
(asn1_der_iterator_next((i)) == ASN1_ITERATOR_PRIMITIVE	\
 && (i)->type == ASN1_INTEGER				\
 && asn1_der_get_bignum((i), (x), (l))			\
 && mpz_sgn((x)) > 0)

int
rsa_public_key_from_der_iterator(struct rsa_public_key *pub,
				 unsigned limit,
				 struct asn1_der_iterator *i)
{
  /* RSAPublicKey ::= SEQUENCE {
         modulus           INTEGER,  -- n
	 publicExponent    INTEGER   -- e
      }
  */

  return (i->type == ASN1_SEQUENCE
	  && asn1_der_decode_constructed_last(i) == ASN1_ITERATOR_PRIMITIVE
	  && asn1_der_get_bignum(i, pub->n, limit) 
	  && mpz_sgn(pub->n) > 0
	  && GET(i, pub->e, limit)
	  && asn1_der_iterator_next(i) == ASN1_ITERATOR_END
	  && rsa_public_key_prepare(pub));
}

int
rsa_private_key_from_der_iterator(struct rsa_public_key *pub,
				  struct rsa_private_key *priv,
				  unsigned limit,
				  struct asn1_der_iterator *i)
{
  /* RSAPrivateKey ::= SEQUENCE {
         version           Version,