bignum.h 3.28 KB
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/* bignum.h
 *
 * bignum operations that are missing from gmp.
 */

/* nettle, low-level cryptographics library
 *
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 * Copyright (C) 2001 Niels Möller
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 *  
 * 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
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 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
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 */
 
#ifndef NETTLE_BIGNUM_H_INCLUDED
#define NETTLE_BIGNUM_H_INCLUDED

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#include "nettle-meta.h"

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#include <gmp.h>
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#include "nettle-types.h"
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#ifdef __cplusplus
extern "C" {
#endif

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/* Size needed for signed encoding, including extra sign byte if
 * necessary. */
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size_t
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nettle_mpz_sizeinbase_256_s(const mpz_t x);
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/* Size needed for unsigned encoding */
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size_t
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nettle_mpz_sizeinbase_256_u(const mpz_t x);

/* Writes an integer as length octets, using big endian byte order,
 * and two's complement for negative numbers. */
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void
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nettle_mpz_get_str_256(size_t length, uint8_t *s, const mpz_t x);
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/* Reads a big endian, two's complement, integer. */
void
nettle_mpz_set_str_256_s(mpz_t x,
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			 size_t length, const uint8_t *s);
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void
nettle_mpz_init_set_str_256_s(mpz_t x,
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			      size_t length, const uint8_t *s);
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/* Similar, but for unsigned format. These function don't interpret
 * the most significant bit as the sign. */
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void
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nettle_mpz_set_str_256_u(mpz_t x,
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			 size_t length, const uint8_t *s);
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void
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nettle_mpz_init_set_str_256_u(mpz_t x,
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			      size_t length, const uint8_t *s);
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/* Returns a uniformly distributed random number 0 <= x < 2^n */
void
nettle_mpz_random_size(mpz_t x,
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		       void *ctx, nettle_random_func *random,
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		       unsigned bits);

/* Returns a number x, almost uniformly random in the range
 * 0 <= x < n. */
void
nettle_mpz_random(mpz_t x, 
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		  void *ctx, nettle_random_func *random,
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		  const mpz_t n);

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void
nettle_next_prime(mpz_t p, mpz_t n, unsigned count, unsigned prime_limit,
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		  void *progress_ctx, nettle_progress_func *progress);
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void
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nettle_random_prime(mpz_t p, unsigned bits, int top_bits_set,
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		    void *ctx, nettle_random_func *random,
		    void *progress_ctx, nettle_progress_func *progress);
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void
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_nettle_generate_pocklington_prime (mpz_t p, mpz_t r,
				    unsigned bits, int top_bits_set, 
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				    void *ctx, nettle_random_func *random, 
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				    const mpz_t p0,
				    const mpz_t q,
				    const mpz_t p0q);
  
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/* sexp parsing */
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struct sexp_iterator;

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/* If LIMIT is non-zero, the number must be at most LIMIT bits.
 * Implies sexp_iterator_next. */
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int
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nettle_mpz_set_sexp(mpz_t x, unsigned limit, struct sexp_iterator *i);
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/* der parsing */
struct asn1_der_iterator;

int
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nettle_asn1_der_get_bignum(struct asn1_der_iterator *iterator,
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			   mpz_t x, unsigned max_bits);
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#ifdef __cplusplus
}
#endif

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#endif /* NETTLE_BIGNUM_H_INCLUDED */