--- /dev/null
+/* bn_x931p.c */
+/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
+ * project 2005.
+ */
+/* ====================================================================
+ * Copyright (c) 2005 The OpenSSL Project. All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * licensing@OpenSSL.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com). This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+
+#include <stdio.h>
+#include <openssl/bn.h>
+
+/* X9.31 routines for prime derivation */
+
+/* X9.31 prime derivation. This is used to generate the primes pi
+ * (p1, p2, q1, q2) from a parameter Xpi by checking successive odd
+ * integers.
+ */
+
+static int bn_x931_derive_pi(BIGNUM *pi, const BIGNUM *Xpi, BN_CTX *ctx,
+ BN_GENCB *cb)
+ {
+ int i = 0;
+ if (!BN_copy(pi, Xpi))
+ return 0;
+ if (!BN_is_odd(pi) && !BN_add_word(pi, 1))
+ return 0;
+ for(;;)
+ {
+ i++;
+ BN_GENCB_call(cb, 0, i);
+ /* NB 27 MR is specificed in X9.31 */
+ if (BN_is_prime_fasttest_ex(pi, 27, ctx, 1, cb))
+ break;
+ if (!BN_add_word(pi, 2))
+ return 0;
+ }
+ BN_GENCB_call(cb, 2, i);
+ return 1;
+ }
+
+/* This is the main X9.31 prime derivation function. From parameters
+ * Xp1, Xp2 and Xp derive the prime p. If the parameters p1 or p2 are
+ * not NULL they will be returned too: this is needed for testing.
+ */
+
+int BN_X931_derive_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
+ const BIGNUM *Xp, const BIGNUM *Xp1, const BIGNUM *Xp2,
+ const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
+ {
+ int ret = 0;
+
+ BIGNUM *t, *p1p2, *pm1;
+
+ /* Only even e supported */
+ if (!BN_is_odd(e))
+ return 0;
+
+ BN_CTX_start(ctx);
+ if (!p1)
+ p1 = BN_CTX_get(ctx);
+
+ if (!p2)
+ p2 = BN_CTX_get(ctx);
+
+ t = BN_CTX_get(ctx);
+
+ p1p2 = BN_CTX_get(ctx);
+
+ pm1 = BN_CTX_get(ctx);
+
+ if (!bn_x931_derive_pi(p1, Xp1, ctx, cb))
+ goto err;
+
+ if (!bn_x931_derive_pi(p2, Xp2, ctx, cb))
+ goto err;
+
+ if (!BN_mul(p1p2, p1, p2, ctx))
+ goto err;
+
+ /* First set p to value of Rp */
+
+ if (!BN_mod_inverse(p, p2, p1, ctx))
+ goto err;
+
+ if (!BN_mul(p, p, p2, ctx))
+ goto err;
+
+ if (!BN_mod_inverse(t, p1, p2, ctx))
+ goto err;
+
+ if (!BN_mul(t, t, p1, ctx))
+ goto err;
+
+ if (!BN_sub(p, p, t))
+ goto err;
+
+ if (p->neg && !BN_add(p, p, p1p2))
+ goto err;
+
+ /* p now equals Rp */
+
+ if (!BN_mod_sub(p, p, Xp, p1p2, ctx))
+ goto err;
+
+ if (!BN_add(p, p, Xp))
+ goto err;
+
+ /* p now equals Yp0 */
+
+ for (;;)
+ {
+ int i = 1;
+ BN_GENCB_call(cb, 0, i++);
+ if (!BN_copy(pm1, p))
+ goto err;
+ if (!BN_sub_word(pm1, 1))
+ goto err;
+ if (!BN_gcd(t, pm1, e, ctx))
+ goto err;
+ if (BN_is_one(t)
+ /* X9.31 specifies 8 MR and 1 Lucas test or any prime test
+ * offering similar or better guarantees 50 MR is considerably
+ * better.
+ */
+ && BN_is_prime_fasttest_ex(p, 50, ctx, 1, cb))
+ break;
+ if (!BN_add(p, p, p1p2))
+ goto err;
+ }
+
+ BN_GENCB_call(cb, 3, 0);
+
+ ret = 1;
+
+ err:
+
+ BN_CTX_end(ctx);
+
+ return ret;
+ }
+
+/* Generate pair of paramters Xp, Xq for X9.31 prime generation.
+ * Note: nbits paramter is sum of number of bits in both.
+ */
+
+int BN_X931_generate_Xpq(BIGNUM *Xp, BIGNUM *Xq, int nbits, BN_CTX *ctx)
+ {
+ BIGNUM *t;
+ int i;
+ /* Number of bits for each prime is of the form
+ * 512+128s for s = 0, 1, ...
+ */
+ if ((nbits < 1024) || (nbits & 0xff))
+ return 0;
+ nbits >>= 1;
+ /* The random value Xp must be between sqrt(2) * 2^(nbits-1) and
+ * 2^nbits - 1. By setting the top two bits we ensure that the lower
+ * bound is exceeded.
+ */
+ if (!BN_rand(Xp, nbits, 1, 0))
+ return 0;
+
+ BN_CTX_start(ctx);
+ t = BN_CTX_get(ctx);
+
+ for (i = 0; i < 1000; i++)
+ {
+ if (!BN_rand(Xq, nbits, 1, 0))
+ return 0;
+ /* Check that |Xp - Xq| > 2^(nbits - 100) */
+ BN_sub(t, Xp, Xq);
+ if (BN_num_bits(t) > (nbits - 100))
+ break;
+ }
+
+ BN_CTX_end(ctx);
+
+ if (i < 1000)
+ return 1;
+
+ return 0;
+
+ }
+
+/* Generate primes using X9.31 algorithm. Of the values p, p1, p2, Xp1
+ * and Xp2 only 'p' needs to be non-NULL. If any of the others are not NULL
+ * the relevant parameter will be stored in it.
+ *
+ * Due to the fact that |Xp - Xq| > 2^(nbits - 100) must be satisfied Xp and Xq
+ * are generated using the previous function and supplied as input.
+ */
+
+int BN_X931_generate_prime_ex(BIGNUM *p, BIGNUM *p1, BIGNUM *p2,
+ BIGNUM *Xp1, BIGNUM *Xp2,
+ const BIGNUM *Xp,
+ const BIGNUM *e, BN_CTX *ctx,
+ BN_GENCB *cb)
+ {
+ int ret = 0;
+
+ BN_CTX_start(ctx);
+ if (!Xp1)
+ Xp1 = BN_CTX_get(ctx);
+ if (!Xp2)
+ Xp2 = BN_CTX_get(ctx);
+
+ if (!BN_rand(Xp1, 101, 0, 0))
+ goto error;
+ if (!BN_rand(Xp2, 101, 0, 0))
+ goto error;
+ if (!BN_X931_derive_prime_ex(p, p1, p2, Xp, Xp1, Xp2, e, ctx, cb))
+ goto error;
+
+ ret = 1;
+
+ error:
+ BN_CTX_end(ctx);
+
+ return ret;
+
+ }
+
projects / oweals / openssl.git / commitdiff