/* R = X mod M Using Barrett reduction. Before using this function _gcry_mpi_barrett_init must have been called to do the precalculations. CTX is the context created by this precalculation and also conveys M. If the Barret reduction could no be done a straightforward reduction method is used. We assume that these conditions are met: Input: x =(x_2k-1 ...x_0)_b m =(m_k-1 ....m_0)_b with m_k-1 != 0 Output: r = x mod m */ void _gcry_mpi_mod_barrett (gcry_mpi_t r, gcry_mpi_t x, mpi_barrett_t ctx) { gcry_mpi_t m = ctx->m; int k = ctx->k; gcry_mpi_t y = ctx->y; gcry_mpi_t r1 = ctx->r1; gcry_mpi_t r2 = ctx->r2; int sign; mpi_normalize (x); if (mpi_get_nlimbs (x) > 2*k ) { mpi_mod (r, x, m); return; } sign = x->sign; x->sign = 0; /* 1. q1 = floor( x / b^k-1) * q2 = q1 * y * q3 = floor( q2 / b^k+1 ) * Actually, we don't need qx, we can work direct on r2 */ mpi_set ( r2, x ); mpi_rshift_limbs ( r2, k-1 ); mpi_mul ( r2, r2, y ); mpi_rshift_limbs ( r2, k+1 ); /* 2. r1 = x mod b^k+1 * r2 = q3 * m mod b^k+1 * r = r1 - r2 * 3. if r < 0 then r = r + b^k+1 */ mpi_set ( r1, x ); if ( r1->nlimbs > k+1 ) /* Quick modulo operation. */ r1->nlimbs = k+1; mpi_mul ( r2, r2, m ); if ( r2->nlimbs > k+1 ) /* Quick modulo operation. */ r2->nlimbs = k+1; mpi_sub ( r, r1, r2 ); if ( mpi_has_sign ( r ) ) { if (!ctx->r3) { ctx->r3 = mpi_alloc ( k + 2 ); mpi_set_ui (ctx->r3, 1); mpi_lshift_limbs (ctx->r3, k + 1 ); } mpi_add ( r, r, ctx->r3 ); } /* 4. while r >= m do r = r - m */ while ( mpi_cmp( r, m ) >= 0 ) mpi_sub ( r, r, m ); x->sign = sign; }
static int mpr_docmp(mpr *op1, mpr *op2, int sign) { int cmp, neg; mpi prod1, prod2; neg = 0; if (sign) { /* if op1 is negative */ if (mpr_num(op1)->sign ^ mpr_den(op1)->sign) { /* if op2 is positive */ if (!(mpr_num(op2)->sign ^ mpr_den(op2)->sign)) return (-1); else neg = 1; } /* if op2 is negative */ else if (mpr_num(op2)->sign ^ mpr_den(op2)->sign) return (1); /* else same sign */ } /* if denominators are equal, compare numerators */ if (mpi_cmpabs(mpr_den(op1), mpr_den(op2)) == 0) { cmp = mpi_cmpabs(mpr_num(op1), mpr_num(op2)); if (cmp == 0) return (0); if (sign && neg) return (cmp < 0 ? 1 : -1); return (cmp); } memset(&prod1, '\0', sizeof(mpi)); memset(&prod2, '\0', sizeof(mpi)); /* "divide" op1 by op2 * if result is smaller than 1, op1 is smaller than op2 */ mpi_mul(&prod1, mpr_num(op1), mpr_den(op2)); mpi_mul(&prod2, mpr_num(op2), mpr_den(op1)); cmp = mpi_cmpabs(&prod1, &prod2); mpi_clear(&prod1); mpi_clear(&prod2); if (sign && neg) return (cmp < 0 ? 1 : -1); return (cmp); }
/**************** * Barrett reduction: We assume that these conditions are met: * Given x =(x_2k-1 ...x_0)_b * m =(m_k-1 ....m_0)_b with m_k-1 != 0 * Output r = x mod m * Before using this function init_barret must be used to calucalte y and k. * Returns: false = no error * true = can't perform barret reduction */ static int calc_barrett( gcry_mpi_t r, gcry_mpi_t x, gcry_mpi_t m, gcry_mpi_t y, int k, gcry_mpi_t r1, gcry_mpi_t r2 ) { int xx = k > 3 ? k-3:0; mpi_normalize( x ); if( mpi_get_nlimbs(x) > 2*k ) return 1; /* can't do it */ /* 1. q1 = floor( x / b^k-1) * q2 = q1 * y * q3 = floor( q2 / b^k+1 ) * Actually, we don't need qx, we can work direct on r2 */ mpi_set( r2, x ); mpi_rshift_limbs( r2, k-1 ); mpi_mul( r2, r2, y ); mpi_rshift_limbs( r2, k+1 ); /* 2. r1 = x mod b^k+1 * r2 = q3 * m mod b^k+1 * r = r1 - r2 * 3. if r < 0 then r = r + b^k+1 */ mpi_set( r1, x ); if( r1->nlimbs > k+1 ) /* quick modulo operation */ r1->nlimbs = k+1; mpi_mul( r2, r2, m ); if( r2->nlimbs > k+1 ) /* quick modulo operation */ r2->nlimbs = k+1; mpi_sub( r, r1, r2 ); if( mpi_has_sign (r) ) { gcry_mpi_t tmp; tmp = mpi_alloc( k + 2 ); mpi_set_ui( tmp, 1 ); mpi_lshift_limbs( tmp, k+1 ); mpi_add( r, r, tmp ); mpi_free(tmp); } /* 4. while r >= m do r = r - m */ while( mpi_cmp( r, m ) >= 0 ) mpi_sub( r, r, m ); return 0; }
void _gcry_mpi_mul_barrett (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, mpi_barrett_t ctx) { mpi_mul (w, u, v); mpi_mod_barrett (w, w, ctx); }
static void barrett_mulm( gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, gcry_mpi_t m, gcry_mpi_t y, int k, gcry_mpi_t r1, gcry_mpi_t r2 ) { mpi_mul(w, u, v); if( calc_barrett( w, w, m, y, k, r1, r2 ) ) mpi_fdiv_r( w, w, m ); }
bool rsa_test(unsigned bits, mt64_context *rand_ctx) { mt64_init_u64(rand_ctx, 1234567890U); rsa_ctx rsa; if (!rsa_init_keygen(&rsa, bits, rand_ctx)) return false; ASSERT(rsa.n != NULL); ASSERT(rsa.phi != NULL); ASSERT(rsa.e != NULL); ASSERT(rsa.d != NULL); mpi_t m = MPI_INITIALIZER; mpi_mul(rsa.e, rsa.d, m); mpi_mod(m, rsa.phi, m); bool result = true; if (!mpi_is_one(m)) { printf("N: "), mpi_print_dec(rsa.n), printf("\n"); printf("E: "), mpi_print_dec(rsa.e), printf("\n"); printf("D: "), mpi_print_dec(rsa.d), printf("\n"); printf("Φ: "), mpi_print_dec(rsa.phi), printf("\n"); printf("E * D mod Φ: "), mpi_print_dec(m), printf("\n"); result = false; } mpi_free(m); rsa_free(&rsa); return result; }
static void do_mul(void) { if( stackidx < 2 ) { fputs("stack underflow\n", stderr); return; } mpi_mul( stack[stackidx-2], stack[stackidx-2], stack[stackidx-1] ); stackidx--; }
void mpr_div(mpr *rop, mpr *op1, mpr *op2) { /* check if temporary storage is required */ if (op1 == op2 && rop == op1) { mpi prod; memset(&prod, '\0', sizeof(mpi)); mpi_mul(&prod, mpr_num(op1), mpr_den(op2)); mpi_mul(mpr_den(rop), mpr_num(op2), mpr_den(op1)); mpi_set(mpr_num(rop), &prod); mpi_clear(&prod); } else { mpi_mul(mpr_num(rop), mpr_num(op1), mpr_den(op2)); mpi_mul(mpr_den(rop), mpr_num(op2), mpr_den(op1)); } }
/**************** * Test whether the secret key is valid. * Returns: true if this is a valid key. */ static int check_secret_key( RSA_secret_key *sk ) { int rc; gcry_mpi_t temp = mpi_alloc( mpi_get_nlimbs(sk->p)*2 ); mpi_mul(temp, sk->p, sk->q ); rc = mpi_cmp( temp, sk->n ); mpi_free(temp); return !rc; }
void mpi_muli(mpi *rop, mpi *op1, long op2) { BNS digs[2]; mpi op; op.digs = (BNS*)digs; _mpi_seti(&op, op2); mpi_mul(rop, op1, &op); }
static void mpr_addsub(mpr *rop, mpr *op1, mpr *op2, int sub) { mpi prod1, prod2; memset(&prod1, '\0', sizeof(mpi)); memset(&prod2, '\0', sizeof(mpi)); mpi_mul(&prod1, mpr_num(op1), mpr_den(op2)); mpi_mul(&prod2, mpr_num(op2), mpr_den(op1)); if (sub) mpi_sub(mpr_num(rop), &prod1, &prod2); else mpi_add(mpr_num(rop), &prod1, &prod2); mpi_clear(&prod1); mpi_clear(&prod2); mpi_mul(mpr_den(rop), mpr_den(op1), mpr_den(op2)); }
int mpi_crt_step(mpi_crt_ctx *ctx, const mpi *a_i, const mpi *m_i) { if (ctx->i == 0) { mpi_init_mpi(ctx->x, a_i); mpi_init_mpi(ctx->m, m_i); } else { mpi_t u, v, gcd; mpi_init(u); mpi_init(v); mpi_init(gcd); mpi_gcdext(ctx->m, m_i, u, v, gcd); if (!mpi_is_one(gcd)) { mpi_free(u); mpi_free(v); mpi_free(gcd); mpi_free(ctx->x); mpi_free(ctx->m); ctx->i = 0; return -1; } mpi_mul(u, ctx->m, u); mpi_mul(u, a_i, u); mpi_mul(v, m_i, v); mpi_mul(v, ctx->x, v); mpi_add(u, v, ctx->x); mpi_mul(ctx->m, m_i, ctx->m); mpi_mod(ctx->x, ctx->m, ctx->x); mpi_free(u); mpi_free(v); mpi_free(gcd); } ctx->i++; return 0; }
static void sign(gcry_mpi_t a, gcry_mpi_t b, gcry_mpi_t input, ELG_secret_key *skey ) { gcry_mpi_t k; gcry_mpi_t t = mpi_alloc( mpi_get_nlimbs(a) ); gcry_mpi_t inv = mpi_alloc( mpi_get_nlimbs(a) ); gcry_mpi_t p_1 = mpi_copy(skey->p); /* * b = (t * inv) mod (p-1) * b = (t * inv(k,(p-1),(p-1)) mod (p-1) * b = (((M-x*a) mod (p-1)) * inv(k,(p-1),(p-1))) mod (p-1) * */ mpi_sub_ui(p_1, p_1, 1); k = gen_k( skey->p, 0 /* no small K ! */ ); gcry_mpi_powm( a, skey->g, k, skey->p ); mpi_mul(t, skey->x, a ); mpi_subm(t, input, t, p_1 ); mpi_invm(inv, k, p_1 ); mpi_mulm(b, t, inv, p_1 ); #if 0 if( DBG_CIPHER ) { log_mpidump("elg sign p= ", skey->p); log_mpidump("elg sign g= ", skey->g); log_mpidump("elg sign y= ", skey->y); log_mpidump("elg sign x= ", skey->x); log_mpidump("elg sign k= ", k); log_mpidump("elg sign M= ", input); log_mpidump("elg sign a= ", a); log_mpidump("elg sign b= ", b); } #endif mpi_free(k); mpi_free(t); mpi_free(inv); mpi_free(p_1); }
/* Scalar point multiplication - the main function for ECC. If takes an integer SCALAR and a POINT as well as the usual context CTX. RESULT will be set to the resulting point. */ void _gcry_mpi_ec_mul_point (mpi_point_t result, gcry_mpi_t scalar, mpi_point_t point, mpi_ec_t ctx) { #if 0 /* Simple left to right binary method. GECC Algorithm 3.27 */ unsigned int nbits; int i; nbits = mpi_get_nbits (scalar); mpi_set_ui (result->x, 1); mpi_set_ui (result->y, 1); mpi_set_ui (result->z, 0); for (i=nbits-1; i >= 0; i--) { _gcry_mpi_ec_dup_point (result, result, ctx); if (mpi_test_bit (scalar, i) == 1) _gcry_mpi_ec_add_points (result, result, point, ctx); } #else gcry_mpi_t x1, y1, z1, k, h, yy; unsigned int i, loops; mpi_point_struct p1, p2, p1inv; x1 = mpi_alloc_like (ctx->p); y1 = mpi_alloc_like (ctx->p); h = mpi_alloc_like (ctx->p); k = mpi_copy (scalar); yy = mpi_copy (point->y); if ( mpi_is_neg (k) ) { k->sign = 0; ec_invm (yy, yy, ctx); } if (!mpi_cmp_ui (point->z, 1)) { mpi_set (x1, point->x); mpi_set (y1, yy); } else { gcry_mpi_t z2, z3; z2 = mpi_alloc_like (ctx->p); z3 = mpi_alloc_like (ctx->p); ec_mulm (z2, point->z, point->z, ctx); ec_mulm (z3, point->z, z2, ctx); ec_invm (z2, z2, ctx); ec_mulm (x1, point->x, z2, ctx); ec_invm (z3, z3, ctx); ec_mulm (y1, yy, z3, ctx); mpi_free (z2); mpi_free (z3); } z1 = mpi_copy (mpi_const (MPI_C_ONE)); mpi_mul (h, k, mpi_const (MPI_C_THREE)); /* h = 3k */ loops = mpi_get_nbits (h); if (loops < 2) { /* If SCALAR is zero, the above mpi_mul sets H to zero and thus LOOPs will be zero. To avoid an underflow of I in the main loop we set LOOP to 2 and the result to (0,0,0). */ loops = 2; mpi_clear (result->x); mpi_clear (result->y); mpi_clear (result->z); } else { mpi_set (result->x, point->x); mpi_set (result->y, yy); mpi_set (result->z, point->z); } mpi_free (yy); yy = NULL; p1.x = x1; x1 = NULL; p1.y = y1; y1 = NULL; p1.z = z1; z1 = NULL; point_init (&p2); point_init (&p1inv); for (i=loops-2; i > 0; i--) { _gcry_mpi_ec_dup_point (result, result, ctx); if (mpi_test_bit (h, i) == 1 && mpi_test_bit (k, i) == 0) { point_set (&p2, result); _gcry_mpi_ec_add_points (result, &p2, &p1, ctx); } if (mpi_test_bit (h, i) == 0 && mpi_test_bit (k, i) == 1) { point_set (&p2, result); /* Invert point: y = p - y mod p */ point_set (&p1inv, &p1); ec_subm (p1inv.y, ctx->p, p1inv.y, ctx); _gcry_mpi_ec_add_points (result, &p2, &p1inv, ctx); } } point_free (&p1); point_free (&p2); point_free (&p1inv); mpi_free (h); mpi_free (k); #endif }
static void ec_mulm (gcry_mpi_t w, gcry_mpi_t u, gcry_mpi_t v, mpi_ec_t ctx) { #if 0 /* NOTE: This code works only for limb sizes of 32 bit. */ mpi_limb_t *wp, *sp; if (ctx->nist_nbits == 192) { mpi_mul (w, u, v); mpi_resize (w, 12); wp = w->d; sp = ctx->s[0]->d; sp[0*2+0] = wp[0*2+0]; sp[0*2+1] = wp[0*2+1]; sp[1*2+0] = wp[1*2+0]; sp[1*2+1] = wp[1*2+1]; sp[2*2+0] = wp[2*2+0]; sp[2*2+1] = wp[2*2+1]; sp = ctx->s[1]->d; sp[0*2+0] = wp[3*2+0]; sp[0*2+1] = wp[3*2+1]; sp[1*2+0] = wp[3*2+0]; sp[1*2+1] = wp[3*2+1]; sp[2*2+0] = 0; sp[2*2+1] = 0; sp = ctx->s[2]->d; sp[0*2+0] = 0; sp[0*2+1] = 0; sp[1*2+0] = wp[4*2+0]; sp[1*2+1] = wp[4*2+1]; sp[2*2+0] = wp[4*2+0]; sp[2*2+1] = wp[4*2+1]; sp = ctx->s[3]->d; sp[0*2+0] = wp[5*2+0]; sp[0*2+1] = wp[5*2+1]; sp[1*2+0] = wp[5*2+0]; sp[1*2+1] = wp[5*2+1]; sp[2*2+0] = wp[5*2+0]; sp[2*2+1] = wp[5*2+1]; ctx->s[0]->nlimbs = 6; ctx->s[1]->nlimbs = 6; ctx->s[2]->nlimbs = 6; ctx->s[3]->nlimbs = 6; mpi_add (ctx->c, ctx->s[0], ctx->s[1]); mpi_add (ctx->c, ctx->c, ctx->s[2]); mpi_add (ctx->c, ctx->c, ctx->s[3]); while ( mpi_cmp (ctx->c, ctx->p ) >= 0 ) mpi_sub ( ctx->c, ctx->c, ctx->p ); mpi_set (w, ctx->c); } else if (ctx->nist_nbits == 384) { int i; mpi_mul (w, u, v); mpi_resize (w, 24); wp = w->d; #define NEXT(a) do { ctx->s[(a)]->nlimbs = 12; \ sp = ctx->s[(a)]->d; \ i = 0; } while (0) #define X(a) do { sp[i++] = wp[(a)];} while (0) #define X0(a) do { sp[i++] = 0; } while (0) NEXT(0); X(0);X(1);X(2);X(3);X(4);X(5);X(6);X(7);X(8);X(9);X(10);X(11); NEXT(1); X0();X0();X0();X0();X(21);X(22);X(23);X0();X0();X0();X0();X0(); NEXT(2); X(12);X(13);X(14);X(15);X(16);X(17);X(18);X(19);X(20);X(21);X(22);X(23); NEXT(3); X(21);X(22);X(23);X(12);X(13);X(14);X(15);X(16);X(17);X(18);X(19);X(20); NEXT(4); X0();X(23);X0();X(20);X(12);X(13);X(14);X(15);X(16);X(17);X(18);X(19); NEXT(5); X0();X0();X0();X0();X(20);X(21);X(22);X(23);X0();X0();X0();X0(); NEXT(6); X(20);X0();X0();X(21);X(22);X(23);X0();X0();X0();X0();X0();X0(); NEXT(7); X(23);X(12);X(13);X(14);X(15);X(16);X(17);X(18);X(19);X(20);X(21);X(22); NEXT(8); X0();X(20);X(21);X(22);X(23);X0();X0();X0();X0();X0();X0();X0(); NEXT(9); X0();X0();X0();X(23);X(23);X0();X0();X0();X0();X0();X0();X0(); #undef X0 #undef X #undef NEXT mpi_add (ctx->c, ctx->s[0], ctx->s[1]); mpi_add (ctx->c, ctx->c, ctx->s[1]); mpi_add (ctx->c, ctx->c, ctx->s[2]); mpi_add (ctx->c, ctx->c, ctx->s[3]); mpi_add (ctx->c, ctx->c, ctx->s[4]); mpi_add (ctx->c, ctx->c, ctx->s[5]); mpi_add (ctx->c, ctx->c, ctx->s[6]); mpi_sub (ctx->c, ctx->c, ctx->s[7]); mpi_sub (ctx->c, ctx->c, ctx->s[8]); mpi_sub (ctx->c, ctx->c, ctx->s[9]); while ( mpi_cmp (ctx->c, ctx->p ) >= 0 ) mpi_sub ( ctx->c, ctx->c, ctx->p ); while ( ctx->c->sign ) mpi_add ( ctx->c, ctx->c, ctx->p ); mpi_set (w, ctx->c); } else #endif /*0*/ mpi_mulm (w, u, v, ctx->p); }
void mpi_mulm( MPI w, MPI u, MPI v, MPI m) { mpi_mul(w, u, v); mpi_fdiv_r( w, w, m ); }
/**************** * We do not need to use the strongest RNG because we gain no extra * security from it - The prime number is public and we could also * offer the factors for those who are willing to check that it is * indeed a strong prime. With ALL_FACTORS set to true all afcors of * prime-1 are returned in FACTORS. * * mode 0: Standard * 1: Make sure that at least one factor is of size qbits. */ static gcry_err_code_t prime_generate_internal (int mode, gcry_mpi_t *prime_generated, unsigned int pbits, unsigned int qbits, gcry_mpi_t g, gcry_mpi_t **ret_factors, gcry_random_level_t randomlevel, unsigned int flags, int all_factors, gcry_prime_check_func_t cb_func, void *cb_arg) { gcry_err_code_t err = 0; gcry_mpi_t *factors_new = NULL; /* Factors to return to the caller. */ gcry_mpi_t *factors = NULL; /* Current factors. */ gcry_mpi_t *pool = NULL; /* Pool of primes. */ unsigned char *perms = NULL; /* Permutations of POOL. */ gcry_mpi_t q_factor = NULL; /* Used if QBITS is non-zero. */ unsigned int fbits = 0; /* Length of prime factors. */ unsigned int n = 0; /* Number of factors. */ unsigned int m = 0; /* Number of primes in pool. */ gcry_mpi_t q = NULL; /* First prime factor. */ gcry_mpi_t prime = NULL; /* Prime candidate. */ unsigned int nprime = 0; /* Bits of PRIME. */ unsigned int req_qbits; /* The original QBITS value. */ gcry_mpi_t val_2; /* For check_prime(). */ unsigned int is_secret = (flags & GCRY_PRIME_FLAG_SECRET); unsigned int count1 = 0, count2 = 0; unsigned int i = 0, j = 0; if (pbits < 48) return GPG_ERR_INV_ARG; /* If QBITS is not given, assume a reasonable value. */ if (!qbits) qbits = pbits / 3; req_qbits = qbits; /* Find number of needed prime factors. */ for (n = 1; (pbits - qbits - 1) / n >= qbits; n++) ; n--; val_2 = mpi_alloc_set_ui (2); if ((! n) || ((mode == 1) && (n < 2))) { err = GPG_ERR_INV_ARG; goto leave; } if (mode == 1) { n--; fbits = (pbits - 2 * req_qbits -1) / n; qbits = pbits - req_qbits - n * fbits; } else { fbits = (pbits - req_qbits -1) / n; qbits = pbits - n * fbits; } if (DBG_CIPHER) log_debug ("gen prime: pbits=%u qbits=%u fbits=%u/%u n=%d\n", pbits, req_qbits, qbits, fbits, n); prime = gcry_mpi_new (pbits); /* Generate first prime factor. */ q = gen_prime (qbits, is_secret, randomlevel, NULL, NULL); if (mode == 1) q_factor = gen_prime (req_qbits, is_secret, randomlevel, NULL, NULL); /* Allocate an array to hold the factors + 2 for later usage. */ factors = gcry_calloc (n + 2, sizeof (*factors)); if (!factors) { err = gpg_err_code_from_errno (errno); goto leave; } /* Make a pool of 3n+5 primes (this is an arbitrary value). */ m = n * 3 + 5; if (mode == 1) /* Need some more (for e.g. DSA). */ m += 5; if (m < 25) m = 25; pool = gcry_calloc (m , sizeof (*pool)); if (! pool) { err = gpg_err_code_from_errno (errno); goto leave; } /* Permutate over the pool of primes. */ do { next_try: if (! perms) { /* Allocate new primes. */ for(i = 0; i < m; i++) { mpi_free (pool[i]); pool[i] = NULL; } /* Init m_out_of_n(). */ perms = gcry_calloc (1, m); if (! perms) { err = gpg_err_code_from_errno (errno); goto leave; } for(i = 0; i < n; i++) { perms[i] = 1; pool[i] = gen_prime (fbits, is_secret, randomlevel, NULL, NULL); factors[i] = pool[i]; } } else { m_out_of_n ((char*)perms, n, m); for (i = j = 0; (i < m) && (j < n); i++) if (perms[i]) { if(! pool[i]) pool[i] = gen_prime (fbits, 0, 1, NULL, NULL); factors[j++] = pool[i]; } if (i == n) { gcry_free (perms); perms = NULL; progress ('!'); goto next_try; /* Allocate new primes. */ } } /* Generate next prime candidate: p = 2 * q [ * q_factor] * factor_0 * factor_1 * ... * factor_n + 1. */ mpi_set (prime, q); mpi_mul_ui (prime, prime, 2); if (mode == 1) mpi_mul (prime, prime, q_factor); for(i = 0; i < n; i++) mpi_mul (prime, prime, factors[i]); mpi_add_ui (prime, prime, 1); nprime = mpi_get_nbits (prime); if (nprime < pbits) { if (++count1 > 20) { count1 = 0; qbits++; progress('>'); mpi_free (q); q = gen_prime (qbits, 0, 0, NULL, NULL); goto next_try; } } else count1 = 0; if (nprime > pbits) { if (++count2 > 20) { count2 = 0; qbits--; progress('<'); mpi_free (q); q = gen_prime (qbits, 0, 0, NULL, NULL); goto next_try; } } else count2 = 0; } while (! ((nprime == pbits) && check_prime (prime, val_2, cb_func, cb_arg))); if (DBG_CIPHER) { progress ('\n'); log_mpidump ("prime : ", prime); log_mpidump ("factor q: ", q); if (mode == 1) log_mpidump ("factor q0: ", q_factor); for (i = 0; i < n; i++) log_mpidump ("factor pi: ", factors[i]); log_debug ("bit sizes: prime=%u, q=%u", mpi_get_nbits (prime), mpi_get_nbits (q)); if (mode == 1) log_debug (", q0=%u", mpi_get_nbits (q_factor)); for (i = 0; i < n; i++) log_debug (", p%d=%u", i, mpi_get_nbits (factors[i])); progress('\n'); } if (ret_factors) { /* Caller wants the factors. */ factors_new = gcry_calloc (n + 4, sizeof (*factors_new)); if (! factors_new) { err = gpg_err_code_from_errno (errno); goto leave; } if (all_factors) { i = 0; factors_new[i++] = gcry_mpi_set_ui (NULL, 2); factors_new[i++] = mpi_copy (q); if (mode == 1) factors_new[i++] = mpi_copy (q_factor); for(j=0; j < n; j++) factors_new[i++] = mpi_copy (factors[j]); } else { i = 0; if (mode == 1) { factors_new[i++] = mpi_copy (q_factor); for (; i <= n; i++) factors_new[i] = mpi_copy (factors[i]); } else for (; i < n; i++ ) factors_new[i] = mpi_copy (factors[i]); } } if (g) { /* Create a generator (start with 3). */ gcry_mpi_t tmp = mpi_alloc (mpi_get_nlimbs (prime)); gcry_mpi_t b = mpi_alloc (mpi_get_nlimbs (prime)); gcry_mpi_t pmin1 = mpi_alloc (mpi_get_nlimbs (prime)); if (mode == 1) err = GPG_ERR_NOT_IMPLEMENTED; else { factors[n] = q; factors[n + 1] = mpi_alloc_set_ui (2); mpi_sub_ui (pmin1, prime, 1); mpi_set_ui (g, 2); do { mpi_add_ui (g, g, 1); if (DBG_CIPHER) { log_debug ("checking g:"); gcry_mpi_dump (g); log_printf ("\n"); } else progress('^'); for (i = 0; i < n + 2; i++) { mpi_fdiv_q (tmp, pmin1, factors[i]); /* No mpi_pow(), but it is okay to use this with mod prime. */ gcry_mpi_powm (b, g, tmp, prime); if (! mpi_cmp_ui (b, 1)) break; } if (DBG_CIPHER) progress('\n'); } while (i < n + 2); mpi_free (factors[n+1]); mpi_free (tmp); mpi_free (b); mpi_free (pmin1); } } if (! DBG_CIPHER) progress ('\n'); leave: if (pool) { for(i = 0; i < m; i++) mpi_free (pool[i]); gcry_free (pool); } if (factors) gcry_free (factors); /* Factors are shallow copies. */ if (perms) gcry_free (perms); mpi_free (val_2); mpi_free (q); mpi_free (q_factor); if (! err) { *prime_generated = prime; if (ret_factors) *ret_factors = factors_new; } else { if (factors_new) { for (i = 0; factors_new[i]; i++) mpi_free (factors_new[i]); gcry_free (factors_new); } mpi_free (prime); } return err; }
int mpi_mulm(MPI w, MPI u, MPI v, MPI m) { if (mpi_mul(w, u, v) < 0) return -ENOMEM; return mpi_fdiv_r(w, w, m); }
/**************** * We do not need to use the strongest RNG because we gain no extra * security from it - The prime number is public and we could also * offer the factors for those who are willing to check that it is * indeed a strong prime. * * mode 0: Standard * 1: Make sure that at least one factor is of size qbits. */ MPI generate_elg_prime( int mode, unsigned pbits, unsigned qbits, MPI g, MPI **ret_factors ) { int n; /* number of factors */ int m; /* number of primes in pool */ unsigned fbits; /* length of prime factors */ MPI *factors; /* current factors */ MPI *pool; /* pool of primes */ MPI q; /* first prime factor (variable)*/ MPI prime; /* prime test value */ MPI q_factor; /* used for mode 1 */ byte *perms = NULL; int i, j; int count1, count2; unsigned nprime; unsigned req_qbits = qbits; /* the requested q bits size */ MPI val_2 = mpi_alloc_set_ui( 2 ); /* find number of needed prime factors */ for(n=1; (pbits - qbits - 1) / n >= qbits; n++ ) ; n--; if( !n || (mode==1 && n < 2) ) log_fatal("can't gen prime with pbits=%u qbits=%u\n", pbits, qbits ); if( mode == 1 ) { n--; fbits = (pbits - 2*req_qbits -1) / n; qbits = pbits - req_qbits - n*fbits; } else { fbits = (pbits - req_qbits -1) / n; qbits = pbits - n*fbits; } if( DBG_CIPHER ) log_debug("gen prime: pbits=%u qbits=%u fbits=%u/%u n=%d\n", pbits, req_qbits, qbits, fbits, n ); prime = mpi_alloc( (pbits + BITS_PER_MPI_LIMB - 1) / BITS_PER_MPI_LIMB ); q = gen_prime( qbits, 0, 0 ); q_factor = mode==1? gen_prime( req_qbits, 0, 0 ) : NULL; /* allocate an array to hold the factors + 2 for later usage */ factors = m_alloc_clear( (n+2) * sizeof *factors ); /* make a pool of 3n+5 primes (this is an arbitrary value) */ m = n*3+5; if( mode == 1 ) m += 5; /* need some more for DSA */ if( m < 25 ) m = 25; pool = m_alloc_clear( m * sizeof *pool ); /* permutate over the pool of primes */ count1=count2=0; do { next_try: if( !perms ) { /* allocate new primes */ for(i=0; i < m; i++ ) { mpi_free(pool[i]); pool[i] = NULL; } /* init m_out_of_n() */ perms = m_alloc_clear( m ); for(i=0; i < n; i++ ) { perms[i] = 1; pool[i] = gen_prime( fbits, 0, 0 ); factors[i] = pool[i]; } } else { m_out_of_n( perms, n, m ); for(i=j=0; i < m && j < n ; i++ ) if( perms[i] ) { if( !pool[i] ) pool[i] = gen_prime( fbits, 0, 0 ); factors[j++] = pool[i]; } if( i == n ) { m_free(perms); perms = NULL; progress('!'); goto next_try; /* allocate new primes */ } } mpi_set( prime, q ); mpi_mul_ui( prime, prime, 2 ); if( mode == 1 ) mpi_mul( prime, prime, q_factor ); for(i=0; i < n; i++ ) mpi_mul( prime, prime, factors[i] ); mpi_add_ui( prime, prime, 1 ); nprime = mpi_get_nbits(prime); if( nprime < pbits ) { if( ++count1 > 20 ) { count1 = 0; qbits++; progress('>'); mpi_free (q); q = gen_prime( qbits, 0, 0 ); goto next_try; } } else count1 = 0; if( nprime > pbits ) { if( ++count2 > 20 ) { count2 = 0; qbits--; progress('<'); mpi_free (q); q = gen_prime( qbits, 0, 0 ); goto next_try; } } else count2 = 0; } while( !(nprime == pbits && check_prime( prime, val_2 )) ); if( DBG_CIPHER ) { progress('\n'); log_mpidump( "prime : ", prime ); log_mpidump( "factor q: ", q ); if( mode == 1 ) log_mpidump( "factor q0: ", q_factor ); for(i=0; i < n; i++ ) log_mpidump( "factor pi: ", factors[i] ); log_debug("bit sizes: prime=%u, q=%u", mpi_get_nbits(prime), mpi_get_nbits(q) ); if( mode == 1 ) fprintf(stderr, ", q0=%u", mpi_get_nbits(q_factor) ); for(i=0; i < n; i++ ) fprintf(stderr, ", p%d=%u", i, mpi_get_nbits(factors[i]) ); progress('\n'); } if( ret_factors ) { /* caller wants the factors */ *ret_factors = m_alloc_clear( (n+2) * sizeof **ret_factors); i = 0; if( mode == 1 ) { (*ret_factors)[i++] = mpi_copy( q_factor ); for(; i <= n; i++ ) (*ret_factors)[i] = mpi_copy( factors[i] ); } else { for(; i < n; i++ ) (*ret_factors)[i] = mpi_copy( factors[i] ); } } if( g ) { /* create a generator (start with 3)*/ MPI tmp = mpi_alloc( mpi_get_nlimbs(prime) ); MPI b = mpi_alloc( mpi_get_nlimbs(prime) ); MPI pmin1 = mpi_alloc( mpi_get_nlimbs(prime) ); if( mode == 1 ) BUG(); /* not yet implemented */ factors[n] = q; factors[n+1] = mpi_alloc_set_ui(2); mpi_sub_ui( pmin1, prime, 1 ); mpi_set_ui(g,2); do { mpi_add_ui(g, g, 1); if( DBG_CIPHER ) { log_debug("checking g: "); mpi_print( stderr, g, 1 ); } else progress('^'); for(i=0; i < n+2; i++ ) { /*fputc('~', stderr);*/ mpi_fdiv_q(tmp, pmin1, factors[i] ); /* (no mpi_pow(), but it is okay to use this with mod prime) */ mpi_powm(b, g, tmp, prime ); if( !mpi_cmp_ui(b, 1) ) break; } if( DBG_CIPHER ) progress('\n'); } while( i < n+2 ); mpi_free(factors[n+1]); mpi_free(tmp); mpi_free(b); mpi_free(pmin1); } if( !DBG_CIPHER ) progress('\n'); m_free( factors ); /* (factors are shallow copies) */ for(i=0; i < m; i++ ) mpi_free( pool[i] ); m_free( pool ); m_free(perms); mpi_free(val_2); mpi_free(q); return prime; }
/**************** * Calculate the multiplicative inverse X of A mod N * That is: Find the solution x for * 1 = (a*x) mod n */ int _gcry_mpi_invm (gcry_mpi_t x, gcry_mpi_t a, gcry_mpi_t n) { #if 0 gcry_mpi_t u, v, u1, u2, u3, v1, v2, v3, q, t1, t2, t3; gcry_mpi_t ta, tb, tc; u = mpi_copy(a); v = mpi_copy(n); u1 = mpi_alloc_set_ui(1); u2 = mpi_alloc_set_ui(0); u3 = mpi_copy(u); v1 = mpi_alloc_set_ui(0); v2 = mpi_alloc_set_ui(1); v3 = mpi_copy(v); q = mpi_alloc( mpi_get_nlimbs(u)+1 ); t1 = mpi_alloc( mpi_get_nlimbs(u)+1 ); t2 = mpi_alloc( mpi_get_nlimbs(u)+1 ); t3 = mpi_alloc( mpi_get_nlimbs(u)+1 ); while( mpi_cmp_ui( v3, 0 ) ) { mpi_fdiv_q( q, u3, v3 ); mpi_mul(t1, v1, q); mpi_mul(t2, v2, q); mpi_mul(t3, v3, q); mpi_sub(t1, u1, t1); mpi_sub(t2, u2, t2); mpi_sub(t3, u3, t3); mpi_set(u1, v1); mpi_set(u2, v2); mpi_set(u3, v3); mpi_set(v1, t1); mpi_set(v2, t2); mpi_set(v3, t3); } /* log_debug("result:\n"); log_mpidump("q =", q ); log_mpidump("u1=", u1); log_mpidump("u2=", u2); log_mpidump("u3=", u3); log_mpidump("v1=", v1); log_mpidump("v2=", v2); */ mpi_set(x, u1); mpi_free(u1); mpi_free(u2); mpi_free(u3); mpi_free(v1); mpi_free(v2); mpi_free(v3); mpi_free(q); mpi_free(t1); mpi_free(t2); mpi_free(t3); mpi_free(u); mpi_free(v); #elif 0 /* Extended Euclid's algorithm (See TAOCP Vol II, 4.5.2, Alg X) * modified according to Michael Penk's solution for Exercise 35 */ /* FIXME: we can simplify this in most cases (see Knuth) */ gcry_mpi_t u, v, u1, u2, u3, v1, v2, v3, t1, t2, t3; unsigned k; int sign; u = mpi_copy(a); v = mpi_copy(n); for(k=0; !mpi_test_bit(u,0) && !mpi_test_bit(v,0); k++ ) { mpi_rshift(u, u, 1); mpi_rshift(v, v, 1); } u1 = mpi_alloc_set_ui(1); u2 = mpi_alloc_set_ui(0); u3 = mpi_copy(u); v1 = mpi_copy(v); /* !-- used as const 1 */ v2 = mpi_alloc( mpi_get_nlimbs(u) ); mpi_sub( v2, u1, u ); v3 = mpi_copy(v); if( mpi_test_bit(u, 0) ) { /* u is odd */ t1 = mpi_alloc_set_ui(0); t2 = mpi_alloc_set_ui(1); t2->sign = 1; t3 = mpi_copy(v); t3->sign = !t3->sign; goto Y4; } else { t1 = mpi_alloc_set_ui(1); t2 = mpi_alloc_set_ui(0); t3 = mpi_copy(u); } do { do { if( mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0) ) { /* one is odd */ mpi_add(t1, t1, v); mpi_sub(t2, t2, u); } mpi_rshift(t1, t1, 1); mpi_rshift(t2, t2, 1); mpi_rshift(t3, t3, 1); Y4: ; } while( !mpi_test_bit( t3, 0 ) ); /* while t3 is even */ if( !t3->sign ) { mpi_set(u1, t1); mpi_set(u2, t2); mpi_set(u3, t3); } else { mpi_sub(v1, v, t1); sign = u->sign; u->sign = !u->sign; mpi_sub(v2, u, t2); u->sign = sign; sign = t3->sign; t3->sign = !t3->sign; mpi_set(v3, t3); t3->sign = sign; } mpi_sub(t1, u1, v1); mpi_sub(t2, u2, v2); mpi_sub(t3, u3, v3); if( t1->sign ) { mpi_add(t1, t1, v); mpi_sub(t2, t2, u); } } while( mpi_cmp_ui( t3, 0 ) ); /* while t3 != 0 */ /* mpi_lshift( u3, k ); */ mpi_set(x, u1); mpi_free(u1); mpi_free(u2); mpi_free(u3); mpi_free(v1); mpi_free(v2); mpi_free(v3); mpi_free(t1); mpi_free(t2); mpi_free(t3); #else /* Extended Euclid's algorithm (See TAOCP Vol II, 4.5.2, Alg X) * modified according to Michael Penk's solution for Exercise 35 * with further enhancement */ gcry_mpi_t u, v, u1, u2=NULL, u3, v1, v2=NULL, v3, t1, t2=NULL, t3; unsigned k; int sign; int odd ; if (!mpi_cmp_ui (a, 0)) return 0; /* Inverse does not exists. */ if (!mpi_cmp_ui (n, 1)) return 0; /* Inverse does not exists. */ u = mpi_copy(a); v = mpi_copy(n); for(k=0; !mpi_test_bit(u,0) && !mpi_test_bit(v,0); k++ ) { mpi_rshift(u, u, 1); mpi_rshift(v, v, 1); } odd = mpi_test_bit(v,0); u1 = mpi_alloc_set_ui(1); if( !odd ) u2 = mpi_alloc_set_ui(0); u3 = mpi_copy(u); v1 = mpi_copy(v); if( !odd ) { v2 = mpi_alloc( mpi_get_nlimbs(u) ); mpi_sub( v2, u1, u ); /* U is used as const 1 */ } v3 = mpi_copy(v); if( mpi_test_bit(u, 0) ) { /* u is odd */ t1 = mpi_alloc_set_ui(0); if( !odd ) { t2 = mpi_alloc_set_ui(1); t2->sign = 1; } t3 = mpi_copy(v); t3->sign = !t3->sign; goto Y4; } else { t1 = mpi_alloc_set_ui(1); if( !odd ) t2 = mpi_alloc_set_ui(0); t3 = mpi_copy(u); } do { do { if( !odd ) { if( mpi_test_bit(t1, 0) || mpi_test_bit(t2, 0) ) { /* one is odd */ mpi_add(t1, t1, v); mpi_sub(t2, t2, u); } mpi_rshift(t1, t1, 1); mpi_rshift(t2, t2, 1); mpi_rshift(t3, t3, 1); } else { if( mpi_test_bit(t1, 0) ) mpi_add(t1, t1, v); mpi_rshift(t1, t1, 1); mpi_rshift(t3, t3, 1); } Y4: ; } while( !mpi_test_bit( t3, 0 ) ); /* while t3 is even */ if( !t3->sign ) { mpi_set(u1, t1); if( !odd ) mpi_set(u2, t2); mpi_set(u3, t3); } else { mpi_sub(v1, v, t1); sign = u->sign; u->sign = !u->sign; if( !odd ) mpi_sub(v2, u, t2); u->sign = sign; sign = t3->sign; t3->sign = !t3->sign; mpi_set(v3, t3); t3->sign = sign; } mpi_sub(t1, u1, v1); if( !odd ) mpi_sub(t2, u2, v2); mpi_sub(t3, u3, v3); if( t1->sign ) { mpi_add(t1, t1, v); if( !odd ) mpi_sub(t2, t2, u); } } while( mpi_cmp_ui( t3, 0 ) ); /* while t3 != 0 */ /* mpi_lshift( u3, k ); */ mpi_set(x, u1); mpi_free(u1); mpi_free(v1); mpi_free(t1); if( !odd ) { mpi_free(u2); mpi_free(v2); mpi_free(t2); } mpi_free(u3); mpi_free(v3); mpi_free(t3); mpi_free(u); mpi_free(v); #endif return 1; }