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3 * (Royal Institute of Technology, Stockholm, Sweden).
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42 #include <krb5-types.h>
49 #include "imath/imath.h"
50 #include "imath/iprime.h"
53 BN2mpz(mpz_t *s, const BIGNUM *bn)
60 len = BN_num_bytes(bn);
63 mp_int_read_unsigned(s, p, len);
74 size = mp_int_unsigned_len(s);
76 if (p == NULL && size != 0)
78 mp_int_to_unsigned(s, p, size);
80 bn = BN_bin2bn(p, size, NULL);
85 static int random_num(mp_int, size_t);
88 setup_blind(mp_int n, mp_int b, mp_int bi)
92 random_num(b, mp_int_count_bits(n));
94 mp_int_invmod(b, n, bi);
98 blind(mp_int in, mp_int b, mp_int e, mp_int n)
102 /* in' = (in * b^e) mod n */
103 mp_int_exptmod(b, e, n, &t1);
104 mp_int_mul(&t1, in, in);
105 mp_int_mod(in, n, in);
110 unblind(mp_int out, mp_int bi, mp_int n)
112 /* out' = (out * 1/b) mod n */
113 mp_int_mul(out, bi, out);
114 mp_int_mod(out, n, out);
118 rsa_private_calculate(mp_int in, mp_int p, mp_int q,
119 mp_int dmp1, mp_int dmq1, mp_int iqmp,
123 mp_int_init(&vp); mp_int_init(&vq); mp_int_init(&u);
125 /* vq = c ^ (d mod (q - 1)) mod q */
126 /* vp = c ^ (d mod (p - 1)) mod p */
127 mp_int_mod(in, p, &u);
128 mp_int_exptmod(&u, dmp1, p, &vp);
129 mp_int_mod(in, q, &u);
130 mp_int_exptmod(&u, dmq1, q, &vq);
132 /* C2 = 1/q mod p (iqmp) */
133 /* u = (vp - vq)C2 mod p. */
134 mp_int_sub(&vp, &vq, &u);
135 if (mp_int_compare_zero(&u) < 0)
136 mp_int_add(&u, p, &u);
137 mp_int_mul(&u, iqmp, &u);
138 mp_int_mod(&u, p, &u);
140 /* c ^ d mod n = vq + u q */
141 mp_int_mul(&u, q, &u);
142 mp_int_add(&u, &vq, out);
156 imath_rsa_public_encrypt(int flen, const unsigned char* from,
157 unsigned char* to, RSA* rsa, int padding)
159 unsigned char *p, *p0;
162 mpz_t enc, dec, n, e;
164 if (padding != RSA_PKCS1_PADDING)
167 size = RSA_size(rsa);
169 if (size < RSA_PKCS1_PADDING_SIZE || size - RSA_PKCS1_PADDING_SIZE < flen)
175 p = p0 = malloc(size - 1);
182 padlen = size - flen - 3;
185 if (RAND_bytes(p, padlen) != 1) {
198 memcpy(p, from, flen);
200 assert((p - p0) == size - 1);
204 mp_int_read_unsigned(&dec, p0, size - 1);
207 res = mp_int_exptmod(&dec, &e, &n, &enc);
214 ssize = mp_int_unsigned_len(&enc);
215 assert(size >= ssize);
216 mp_int_to_unsigned(&enc, to, ssize);
225 imath_rsa_public_decrypt(int flen, const unsigned char* from,
226 unsigned char* to, RSA* rsa, int padding)
233 if (padding != RSA_PKCS1_PADDING)
236 if (flen > RSA_size(rsa))
243 /* Check that the exponent is larger then 3 */
244 if (mp_int_compare_value(&e, 3) <= 0) {
253 mp_int_read_unsigned(&s, rk_UNCONST(from), flen);
255 if (mp_int_compare(&s, &n) >= 0) {
261 res = mp_int_exptmod(&s, &e, &n, &us);
272 size = mp_int_unsigned_len(&us);
273 assert(size <= RSA_size(rsa));
274 mp_int_to_unsigned(&us, p, size);
278 /* head zero was skipped by mp_int_to_unsigned */
284 while (size && *p == 0xff) {
287 if (size == 0 || *p != 0)
291 memmove(to, p, size);
297 imath_rsa_private_encrypt(int flen, const unsigned char* from,
298 unsigned char* to, RSA* rsa, int padding)
300 unsigned char *p, *p0;
303 mpz_t in, out, n, e, b, bi;
304 int blinding = (rsa->flags & RSA_FLAG_NO_BLINDING) == 0;
306 if (padding != RSA_PKCS1_PADDING)
309 size = RSA_size(rsa);
311 if (size < RSA_PKCS1_PADDING_SIZE || size - RSA_PKCS1_PADDING_SIZE < flen)
314 p0 = p = malloc(size);
317 memset(p, 0xff, size - flen - 3);
318 p += size - flen - 3;
320 memcpy(p, from, flen);
322 assert((p - p0) == size);
329 mp_int_read_unsigned(&in, p0, size);
332 if(mp_int_compare_zero(&in) < 0 ||
333 mp_int_compare(&in, &n) >= 0) {
339 setup_blind(&n, &b, &bi);
340 blind(&in, &b, &e, &n);
343 if (rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 && rsa->iqmp) {
344 mpz_t p, q, dmp1, dmq1, iqmp;
348 BN2mpz(&dmp1, rsa->dmp1);
349 BN2mpz(&dmq1, rsa->dmq1);
350 BN2mpz(&iqmp, rsa->iqmp);
352 res = rsa_private_calculate(&in, &p, &q, &dmp1, &dmq1, &iqmp, &out);
363 res = mp_int_exptmod(&in, &d, &n, &out);
372 unblind(&out, &bi, &n);
379 ssize = mp_int_unsigned_len(&out);
380 assert(size >= ssize);
381 mp_int_to_unsigned(&out, to, size);
395 imath_rsa_private_decrypt(int flen, const unsigned char* from,
396 unsigned char* to, RSA* rsa, int padding)
401 mpz_t in, out, n, e, b, bi;
402 int blinding = (rsa->flags & RSA_FLAG_NO_BLINDING) == 0;
404 if (padding != RSA_PKCS1_PADDING)
407 size = RSA_size(rsa);
417 res = mp_int_read_unsigned(&in, rk_UNCONST(from), flen);
423 if(mp_int_compare_zero(&in) < 0 ||
424 mp_int_compare(&in, &n) >= 0) {
430 setup_blind(&n, &b, &bi);
431 blind(&in, &b, &e, &n);
434 if (rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 && rsa->iqmp) {
435 mpz_t p, q, dmp1, dmq1, iqmp;
439 BN2mpz(&dmp1, rsa->dmp1);
440 BN2mpz(&dmq1, rsa->dmq1);
441 BN2mpz(&iqmp, rsa->iqmp);
443 res = rsa_private_calculate(&in, &p, &q, &dmp1, &dmq1, &iqmp, &out);
453 if(mp_int_compare_zero(&in) < 0 ||
454 mp_int_compare(&in, &n) >= 0)
458 res = mp_int_exptmod(&in, &d, &n, &out);
467 unblind(&out, &bi, &n);
475 ssize = mp_int_unsigned_len(&out);
476 assert(size >= ssize);
477 mp_int_to_unsigned(&out, ptr, ssize);
481 /* head zero was skipped by mp_int_to_unsigned */
485 while (size && *ptr != 0) {
492 memmove(to, ptr, size);
504 random_num(mp_int num, size_t len)
513 if (RAND_bytes(p, len) != 1) {
517 res = mp_int_read_unsigned(num, p, len);
524 #define CHECK(f, v) if ((f) != (v)) { goto out; }
527 imath_rsa_generate_key(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb)
529 mpz_t el, p, q, n, d, dmp1, dmq1, iqmp, t1, t2, t3;
551 /* generate p and q so that p != q and bits(pq) ~ bits */
554 BN_GENCB_call(cb, 2, counter++);
555 CHECK(random_num(&p, bits / 2 + 1), 0);
556 CHECK(mp_int_find_prime(&p), MP_TRUE);
558 CHECK(mp_int_sub_value(&p, 1, &t1), MP_OK);
559 CHECK(mp_int_gcd(&t1, &el, &t2), MP_OK);
560 } while(mp_int_compare_value(&t2, 1) != 0);
562 BN_GENCB_call(cb, 3, 0);
566 BN_GENCB_call(cb, 2, counter++);
567 CHECK(random_num(&q, bits / 2 + 1), 0);
568 CHECK(mp_int_find_prime(&q), MP_TRUE);
570 if (mp_int_compare(&p, &q) == 0) /* don't let p and q be the same */
573 CHECK(mp_int_sub_value(&q, 1, &t1), MP_OK);
574 CHECK(mp_int_gcd(&t1, &el, &t2), MP_OK);
575 } while(mp_int_compare_value(&t2, 1) != 0);
578 if (mp_int_compare(&p, &q) < 0)
581 BN_GENCB_call(cb, 3, 1);
583 /* calculate n, n = p * q */
584 CHECK(mp_int_mul(&p, &q, &n), MP_OK);
586 /* calculate d, d = 1/e mod (p - 1)(q - 1) */
587 CHECK(mp_int_sub_value(&p, 1, &t1), MP_OK);
588 CHECK(mp_int_sub_value(&q, 1, &t2), MP_OK);
589 CHECK(mp_int_mul(&t1, &t2, &t3), MP_OK);
590 CHECK(mp_int_invmod(&el, &t3, &d), MP_OK);
592 /* calculate dmp1 dmp1 = d mod (p-1) */
593 CHECK(mp_int_mod(&d, &t1, &dmp1), MP_OK);
594 /* calculate dmq1 dmq1 = d mod (q-1) */
595 CHECK(mp_int_mod(&d, &t2, &dmq1), MP_OK);
596 /* calculate iqmp iqmp = 1/q mod p */
597 CHECK(mp_int_invmod(&q, &p, &iqmp), MP_OK);
599 /* fill in RSA key */
601 rsa->e = mpz2BN(&el);
606 rsa->dmp1 = mpz2BN(&dmp1);
607 rsa->dmq1 = mpz2BN(&dmq1);
608 rsa->iqmp = mpz2BN(&iqmp);
628 imath_rsa_init(RSA *rsa)
634 imath_rsa_finish(RSA *rsa)
639 const RSA_METHOD hc_rsa_imath_method = {
641 imath_rsa_public_encrypt,
642 imath_rsa_public_decrypt,
643 imath_rsa_private_encrypt,
644 imath_rsa_private_decrypt,
653 imath_rsa_generate_key
657 RSA_imath_method(void)
659 return &hc_rsa_imath_method;