static int rsa_private_calculate(mpz_t in, mpz_t p, mpz_t q, mpz_t dmp1, mpz_t dmq1, mpz_t iqmp, mpz_t out) { mpz_t vp, vq, u; mpz_init(vp); mpz_init(vq); mpz_init(u); /* vq = c ^ (d mod (q - 1)) mod q */ /* vp = c ^ (d mod (p - 1)) mod p */ mpz_fdiv_r(vp, in, p); mpz_powm(vp, vp, dmp1, p); mpz_fdiv_r(vq, in, q); mpz_powm(vq, vq, dmq1, q); /* C2 = 1/q mod p (iqmp) */ /* u = (vp - vq)C2 mod p. */ mpz_sub(u, vp, vq); #if 0 if (mp_int_compare_zero(&u) < 0) mp_int_add(&u, p, &u); #endif mpz_mul(u, iqmp, u); mpz_fdiv_r(u, u, p); /* c ^ d mod n = vq + u q */ mpz_mul(u, q, u); mpz_add(out, u, vq); mpz_clear(vp); mpz_clear(vq); mpz_clear(u); return 0; }
static mp_result s_rsa_transform(mp_int msg, mp_int exp, mp_int mod, mp_int out) { if(mp_int_compare_zero(msg) < 0 || mp_int_compare(msg, mod) >= 0) return MP_RANGE; return mp_int_exptmod(msg, exp, mod, out); }
/* Compute mul * atan(1/x) to prec digits of precision, and store the result in sum. Computes atan(1/x) using the formula: 1 1 1 1 atan(1/x) = --- - ---- + ---- - ---- + ... x 3x^3 5x^5 7x^7 */ mp_result arctan(mp_small radix, mp_small mul, mp_small x, mp_small prec, mp_int sum) { mpz_t t, v; mp_result res; mp_small rem, sign = 1, coeff = 1; mp_int_init(&t); mp_int_init(&v); ++prec; /* Compute mul * radix^prec * x The initial multiplication by x saves a special case in the loop for the first term of the series. */ if ((res = mp_int_expt_value(radix, prec, &t)) != MP_OK || (res = mp_int_mul_value(&t, mul, &t)) != MP_OK || (res = mp_int_mul_value(&t, x, &t)) != MP_OK) goto CLEANUP; x *= x; /* assumes x <= sqrt(MP_SMALL_MAX) */ mp_int_zero(sum); do { if ((res = mp_int_div_value(&t, x, &t, &rem)) != MP_OK) goto CLEANUP; if ((res = mp_int_div_value(&t, coeff, &v, &rem)) != MP_OK) goto CLEANUP; /* Add or subtract the result depending on the current sign (1 = add) */ if (sign > 0) res = mp_int_add(sum, &v, sum); else res = mp_int_sub(sum, &v, sum); if (res != MP_OK) goto CLEANUP; sign = -sign; coeff += 2; } while (mp_int_compare_zero(&t) != 0); res = mp_int_div_value(sum, radix, sum, NULL); CLEANUP: mp_int_clear(&v); mp_int_clear(&t); return res; }
static int gmp_rsa_private_decrypt(int flen, const unsigned char* from, unsigned char* to, RSA* rsa, int padding) { unsigned char *ptr; size_t size; mpz_t in, out, n, e; if (padding != RSA_PKCS1_PADDING) return -1; size = RSA_size(rsa); if (flen > size) return -2; mpz_init(in); mpz_init(out); BN2mpz(n, rsa->n); BN2mpz(e, rsa->e); mpz_import(in, flen, 1, 1, 1, 0, from); if(mpz_cmp_ui(in, 0) < 0 || mpz_cmp(in, n) >= 0) { size = 0; goto out; } if (rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 && rsa->iqmp) { mpz_t p, q, dmp1, dmq1, iqmp; BN2mpz(p, rsa->p); BN2mpz(q, rsa->q); BN2mpz(dmp1, rsa->dmp1); BN2mpz(dmq1, rsa->dmq1); BN2mpz(iqmp, rsa->iqmp); rsa_private_calculate(in, p, q, dmp1, dmq1, iqmp, out); mpz_clear(p); mpz_clear(q); mpz_clear(dmp1); mpz_clear(dmq1); mpz_clear(iqmp); } else { mpz_t d; #if 0 if(mp_int_compare_zero(&in) < 0 || mp_int_compare(&in, &n) >= 0) return MP_RANGE; #endif BN2mpz(d, rsa->d); mpz_powm(out, in, d, n); mpz_clear(d); } ptr = to; { size_t ssize; mpz_export(ptr, &ssize, 1, 1, 1, 0, out); assert(size >= ssize); size = ssize; } /* head zero was skipped by mp_int_to_unsigned */ if (*ptr != 2) return -3; size--; ptr++; while (size && *ptr != 0) { size--; ptr++; } if (size == 0) return -4; size--; ptr++; memmove(to, ptr, size); out: mpz_clear(e); mpz_clear(n); mpz_clear(in); mpz_clear(out); return size; }
static int gmp_rsa_private_encrypt(int flen, const unsigned char* from, unsigned char* to, RSA* rsa, int padding) { unsigned char *p, *p0; size_t size; mpz_t in, out, n, e; if (padding != RSA_PKCS1_PADDING) return -1; size = RSA_size(rsa); if (size < RSA_PKCS1_PADDING_SIZE || size - RSA_PKCS1_PADDING_SIZE < flen) return -2; p0 = p = malloc(size); *p++ = 0; *p++ = 1; memset(p, 0xff, size - flen - 3); p += size - flen - 3; *p++ = 0; memcpy(p, from, flen); p += flen; assert((p - p0) == size); BN2mpz(n, rsa->n); BN2mpz(e, rsa->e); mpz_init(in); mpz_init(out); mpz_import(in, size, 1, 1, 1, 0, p0); free(p0); #if 0 if(mp_int_compare_zero(&in) < 0 || mp_int_compare(&in, &n) >= 0) { size = 0; goto out; } #endif if (rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 && rsa->iqmp) { mpz_t p, q, dmp1, dmq1, iqmp; BN2mpz(p, rsa->p); BN2mpz(q, rsa->q); BN2mpz(dmp1, rsa->dmp1); BN2mpz(dmq1, rsa->dmq1); BN2mpz(iqmp, rsa->iqmp); rsa_private_calculate(in, p, q, dmp1, dmq1, iqmp, out); mpz_clear(p); mpz_clear(q); mpz_clear(dmp1); mpz_clear(dmq1); mpz_clear(iqmp); } else { mpz_t d; BN2mpz(d, rsa->d); mpz_powm(out, in, d, n); mpz_clear(d); } { size_t ssize; mpz_export(to, &ssize, 1, 1, 1, 0, out); assert(size >= ssize); size = ssize; } mpz_clear(e); mpz_clear(n); mpz_clear(in); mpz_clear(out); return size; }