2 * Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2018-2019, Oracle and/or its affiliates. All rights reserved.
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
11 #include <openssl/err.h>
12 #include <openssl/bn.h>
13 #include <openssl/core.h>
14 #include "crypto/bn.h"
15 #include "crypto/security_bits.h"
16 #include "rsa_local.h"
18 #define RSA_FIPS1864_MIN_KEYGEN_KEYSIZE 2048
19 #define RSA_FIPS1864_MIN_KEYGEN_STRENGTH 112
20 #define RSA_FIPS1864_MAX_KEYGEN_STRENGTH 256
23 * Generate probable primes 'p' & 'q'. See FIPS 186-4 Section B.3.6
24 * "Generation of Probable Primes with Conditions Based on Auxiliary Probable
28 * rsa Object used to store primes p & q.
29 * test Object used for CAVS testing only.that contains..
30 * p1, p2 The returned auxiliary primes for p.
31 * If NULL they are not returned.
32 * Xpout An optionally returned random number used during generation of p.
33 * Xp An optional passed in value (that is random number used during
35 * Xp1, Xp2 Optionally passed in randomly generated numbers from which
36 * auxiliary primes p1 & p2 are calculated. If NULL these values
37 * are generated internally.
38 * q1, q2 The returned auxiliary primes for q.
39 * If NULL they are not returned.
40 * Xqout An optionally returned random number used during generation of q.
41 * Xq An optional passed in value (that is random number used during
43 * Xq1, Xq2 Optionally passed in randomly generated numbers from which
44 * auxiliary primes q1 & q2 are calculated. If NULL these values
45 * are generated internally.
46 * nbits The key size in bits (The size of the modulus n).
47 * e The public exponent.
48 * ctx A BN_CTX object.
49 * cb An optional BIGNUM callback.
50 * Returns: 1 if successful, or 0 otherwise.
52 * p1, p2, q1, q2, Xpout, Xqout are returned if they are not NULL.
53 * Xp, Xp1, Xp2, Xq, Xq1, Xq2 are optionally passed in.
54 * (Required for CAVS testing).
56 int rsa_fips186_4_gen_prob_primes(RSA *rsa, RSA_ACVP_TEST *test, int nbits,
57 const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)
60 /* Temp allocated BIGNUMS */
61 BIGNUM *Xpo = NULL, *Xqo = NULL, *tmp = NULL;
62 /* Intermediate BIGNUMS that can be returned for testing */
63 BIGNUM *p1 = NULL, *p2 = NULL;
64 BIGNUM *q1 = NULL, *q2 = NULL;
65 /* Intermediate BIGNUMS that can be input for testing */
66 BIGNUM *Xpout = NULL, *Xqout = NULL;
67 BIGNUM *Xp = NULL, *Xp1 = NULL, *Xp2 = NULL;
68 BIGNUM *Xq = NULL, *Xq1 = NULL, *Xq2 = NULL;
70 #if defined(FIPS_MODULE) && !defined(OPENSSL_NO_ACVP_TESTS)
85 /* (Step 1) Check key length
86 * NOTE: SP800-131A Rev1 Disallows key lengths of < 2048 bits for RSA
87 * Signature Generation and Key Agree/Transport.
89 if (nbits < RSA_FIPS1864_MIN_KEYGEN_KEYSIZE) {
90 RSAerr(RSA_F_RSA_FIPS186_4_GEN_PROB_PRIMES, RSA_R_KEY_SIZE_TOO_SMALL);
94 if (!rsa_check_public_exponent(e)) {
95 RSAerr(RSA_F_RSA_FIPS186_4_GEN_PROB_PRIMES,
96 RSA_R_PUB_EXPONENT_OUT_OF_RANGE);
100 /* (Step 3) Determine strength and check rand generator strength is ok -
101 * this step is redundant because the generator always returns a higher
102 * strength than is required.
106 tmp = BN_CTX_get(ctx);
107 Xpo = (Xpout != NULL) ? Xpout : BN_CTX_get(ctx);
108 Xqo = (Xqout != NULL) ? Xqout : BN_CTX_get(ctx);
109 if (tmp == NULL || Xpo == NULL || Xqo == NULL)
113 rsa->p = BN_secure_new();
115 rsa->q = BN_secure_new();
116 if (rsa->p == NULL || rsa->q == NULL)
119 /* (Step 4) Generate p, Xp */
120 if (!bn_rsa_fips186_4_gen_prob_primes(rsa->p, Xpo, p1, p2, Xp, Xp1, Xp2,
124 /* (Step 5) Generate q, Xq*/
125 if (!bn_rsa_fips186_4_gen_prob_primes(rsa->q, Xqo, q1, q2, Xq, Xq1,
126 Xq2, nbits, e, ctx, cb))
129 /* (Step 6) |Xp - Xq| > 2^(nbitlen/2 - 100) */
130 ok = rsa_check_pminusq_diff(tmp, Xpo, Xqo, nbits);
136 /* (Step 6) |p - q| > 2^(nbitlen/2 - 100) */
137 ok = rsa_check_pminusq_diff(tmp, rsa->p, rsa->q, nbits);
142 break; /* successfully finished */
147 /* Zeroize any internally generated values that are not returned */
159 * Validates the RSA key size based on the target strength.
160 * See SP800-56Br1 6.3.1.1 (Steps 1a-1b)
163 * nbits The key size in bits.
164 * strength The target strength in bits. -1 means the target
165 * strength is unknown.
166 * Returns: 1 if the key size matches the target strength, or 0 otherwise.
168 int rsa_sp800_56b_validate_strength(int nbits, int strength)
170 int s = (int)ifc_ffc_compute_security_bits(nbits);
172 if (s < RSA_FIPS1864_MIN_KEYGEN_STRENGTH
173 || s > RSA_FIPS1864_MAX_KEYGEN_STRENGTH) {
174 RSAerr(RSA_F_RSA_SP800_56B_VALIDATE_STRENGTH, RSA_R_INVALID_MODULUS);
178 if (strength != -1 && s != strength) {
179 RSAerr(RSA_F_RSA_SP800_56B_VALIDATE_STRENGTH, RSA_R_INVALID_STRENGTH);
187 * Using p & q, calculate other required parameters such as n, d.
188 * as well as the CRT parameters dP, dQ, qInv.
191 * 6.3.1.1 rsakpg1 - basic (Steps 3-4)
192 * 6.3.1.3 rsakpg1 - crt (Step 5)
196 * nbits The key size.
197 * e The public exponent.
198 * ctx A BN_CTX object.
200 * There is a small chance that the generated d will be too small.
201 * Returns: -1 = error,
202 * 0 = d is too small,
205 int rsa_sp800_56b_derive_params_from_pq(RSA *rsa, int nbits,
206 const BIGNUM *e, BN_CTX *ctx)
209 BIGNUM *p1, *q1, *lcm, *p1q1, *gcd;
212 p1 = BN_CTX_get(ctx);
213 q1 = BN_CTX_get(ctx);
214 lcm = BN_CTX_get(ctx);
215 p1q1 = BN_CTX_get(ctx);
216 gcd = BN_CTX_get(ctx);
220 /* LCM((p-1, q-1)) */
221 if (rsa_get_lcm(ctx, rsa->p, rsa->q, lcm, gcd, p1, q1, p1q1) != 1)
230 BN_clear_free(rsa->d);
231 /* (Step 3) d = (e^-1) mod (LCM(p-1, q-1)) */
232 rsa->d = BN_secure_new();
233 if (rsa->d == NULL || BN_mod_inverse(rsa->d, e, lcm, ctx) == NULL)
236 /* (Step 3) return an error if d is too small */
237 if (BN_num_bits(rsa->d) <= (nbits >> 1)) {
242 /* (Step 4) n = pq */
245 if (rsa->n == NULL || !BN_mul(rsa->n, rsa->p, rsa->q, ctx))
248 /* (Step 5a) dP = d mod (p-1) */
249 if (rsa->dmp1 == NULL)
250 rsa->dmp1 = BN_new();
251 if (rsa->dmp1 == NULL || !BN_mod(rsa->dmp1, rsa->d, p1, ctx))
254 /* (Step 5b) dQ = d mod (q-1) */
255 if (rsa->dmq1 == NULL)
256 rsa->dmq1 = BN_secure_new();
257 if (rsa->dmq1 == NULL || !BN_mod(rsa->dmq1, rsa->d, q1, ctx))
260 /* (Step 5c) qInv = (inverse of q) mod p */
262 rsa->iqmp = BN_secure_new();
263 if (rsa->iqmp == NULL
264 || BN_mod_inverse(rsa->iqmp, rsa->q, rsa->p, ctx) == NULL)
295 * Generate a SP800-56B RSA key.
297 * See SP800-56Br1 6.3.1 "RSA Key-Pair Generation with a Fixed Public Exponent"
298 * 6.3.1.1 rsakpg1 - basic
299 * 6.3.1.3 rsakpg1 - crt
301 * See also FIPS 186-4 Section B.3.6
302 * "Generation of Probable Primes with Conditions Based on Auxiliary
306 * rsa The rsa object.
307 * nbits The intended key size in bits.
308 * efixed The public exponent. If NULL a default of 65537 is used.
309 * cb An optional BIGNUM callback.
310 * Returns: 1 if successfully generated otherwise it returns 0.
312 int rsa_sp800_56b_generate_key(RSA *rsa, int nbits, const BIGNUM *efixed,
319 RSA_ACVP_TEST *info = NULL;
321 #if defined(FIPS_MODULE) && !defined(OPENSSL_NO_ACVP_TESTS)
322 info = rsa->acvp_test;
325 /* (Steps 1a-1b) : Currently ignores the strength check */
326 if (!rsa_sp800_56b_validate_strength(nbits, -1))
329 ctx = BN_CTX_new_ex(rsa->libctx);
333 /* Set default if e is not passed in */
334 if (efixed == NULL) {
336 if (e == NULL || !BN_set_word(e, 65537))
339 e = (BIGNUM *)efixed;
341 /* (Step 1c) fixed exponent is checked later .*/
344 /* (Step 2) Generate prime factors */
345 if (!rsa_fips186_4_gen_prob_primes(rsa, info, nbits, e, ctx,
348 /* (Steps 3-5) Compute params d, n, dP, dQ, qInv */
349 ok = rsa_sp800_56b_derive_params_from_pq(rsa, nbits, e, ctx);
354 /* Gets here if computed d is too small - so try again */
357 /* (Step 6) Do pairwise test - optional validity test has been omitted */
358 ret = rsa_sp800_56b_pairwise_test(rsa, ctx);
367 * See SP800-56Br1 6.3.1.3 (Step 6) Perform a pair-wise consistency test by
368 * verifying that: k = (k^e)^d mod n for some integer k where 1 < k < n-1.
370 * Returns 1 if the RSA key passes the pairwise test or 0 it it fails.
372 int rsa_sp800_56b_pairwise_test(RSA *rsa, BN_CTX *ctx)
378 tmp = BN_CTX_get(ctx);
383 ret = (BN_set_word(k, 2)
384 && BN_mod_exp(tmp, k, rsa->e, rsa->n, ctx)
385 && BN_mod_exp(tmp, tmp, rsa->d, rsa->n, ctx)
386 && BN_cmp(k, tmp) == 0);
388 RSAerr(RSA_F_RSA_SP800_56B_PAIRWISE_TEST, RSA_R_PAIRWISE_TEST_FAILURE);