From: Bodo Möller Date: Sun, 14 Apr 2002 13:28:41 +0000 (+0000) Subject: remove disabled code X-Git-Tag: OpenSSL_0_9_7-beta1~102 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=617f461c9d744a47e1f991e939df58519be5414f;p=oweals%2Fopenssl.git remove disabled code --- diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c index 4e409d07bf..603ba31b81 100644 --- a/crypto/ec/ec_mult.c +++ b/crypto/ec/ec_mult.c @@ -61,14 +61,13 @@ /* TODO: optional precomputation of multiples of the generator */ -#if 1 + /* * wNAF-based interleaving multi-exponentation method * () */ - /* Determine the width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. * This is an array r[] of values that are either zero or odd with an * absolute value less than 2^w satisfying @@ -417,314 +416,6 @@ int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, return ret; } -#else - -/* - * Basic interleaving multi-exponentation method - */ - - - -#define EC_window_bits_for_scalar_size(b) \ - ((b) >= 2000 ? 6 : \ - (b) >= 800 ? 5 : \ - (b) >= 300 ? 4 : \ - (b) >= 70 ? 3 : \ - (b) >= 20 ? 2 : \ - 1) -/* For window size 'w' (w >= 2), we compute the odd multiples - * 1*P .. (2^w-1)*P. - * This accounts for 2^(w-1) point additions (neglecting constants), - * each of which requires 16 field multiplications (4 squarings - * and 12 general multiplications) in the case of curves defined - * over GF(p), which are the only curves we have so far. - * - * Converting these precomputed points into affine form takes - * three field multiplications for inverting Z and one squaring - * and three multiplications for adjusting X and Y, i.e. - * 7 multiplications in total (1 squaring and 6 general multiplications), - * again except for constants. - * - * The average number of windows for a 'b' bit scalar is roughly - * b/(w+1). - * Each of these windows (except possibly for the first one, but - * we are ignoring constants anyway) requires one point addition. - * As the precomputed table stores points in affine form, these - * additions take only 11 field multiplications each (3 squarings - * and 8 general multiplications). - * - * So the total workload, except for constants, is - * - * 2^(w-1)*[5 squarings + 18 multiplications] - * + (b/(w+1))*[3 squarings + 8 multiplications] - * - * If we assume that 10 squarings are as costly as 9 multiplications, - * our task is to find the 'w' that, given 'b', minimizes - * - * 2^(w-1)*(5*9 + 18*10) + (b/(w+1))*(3*9 + 8*10) - * = 2^(w-1)*225 + (b/(w+1))*107. - * - * Thus optimal window sizes should be roughly as follows: - * - * w >= 6 if b >= 1414 - * w = 5 if 1413 >= b >= 505 - * w = 4 if 504 >= b >= 169 - * w = 3 if 168 >= b >= 51 - * w = 2 if 50 >= b >= 13 - * w = 1 if 12 >= b - * - * If we assume instead that squarings are exactly as costly as - * multiplications, we have to minimize - * 2^(w-1)*23 + (b/(w+1))*11. - * - * This gives us the following (nearly unchanged) table of optimal - * windows sizes: - * - * w >= 6 if b >= 1406 - * w = 5 if 1405 >= b >= 502 - * w = 4 if 501 >= b >= 168 - * w = 3 if 167 >= b >= 51 - * w = 2 if 50 >= b >= 13 - * w = 1 if 12 >= b - * - * Note that neither table tries to take into account memory usage - * (allocation overhead, code locality etc.). Actual timings with - * NIST curves P-192, P-224, and P-256 with scalars of 192, 224, - * and 256 bits, respectively, show that w = 3 (instead of 4) is - * preferrable; timings with NIST curve P-384 and 384-bit scalars - * confirm that w = 4 is optimal for this case; and timings with - * NIST curve P-521 and 521-bit scalars show that w = 4 (instead - * of 5) is preferrable. So we generously round up all the - * boundaries and use the following table: - * - * w >= 6 if b >= 2000 - * w = 5 if 1999 >= b >= 800 - * w = 4 if 799 >= b >= 300 - * w = 3 if 299 >= b >= 70 - * w = 2 if 69 >= b >= 20 - * w = 1 if 19 >= b - */ - -int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, - size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx) - { - BN_CTX *new_ctx = NULL; - EC_POINT *generator = NULL; - EC_POINT *tmp = NULL; - size_t totalnum; - size_t i, j; - int k, t; - int r_is_at_infinity = 1; - size_t max_bits = 0; - size_t *wsize = NULL; /* individual window sizes */ - unsigned long *wbits = NULL; /* individual window contents */ - int *wpos = NULL; /* position of bottom bit of current individual windows - * (wpos[i] is valid if wbits[i] != 0) */ - size_t num_val; - EC_POINT **val = NULL; /* precomputation */ - EC_POINT **v; - EC_POINT ***val_sub = NULL; /* pointers to sub-arrays of 'val' */ - int ret = 0; - - if (scalar != NULL) - { - generator = EC_GROUP_get0_generator(group); - if (generator == NULL) - { - ECerr(EC_F_EC_POINTS_MUL, EC_R_UNDEFINED_GENERATOR); - return 0; - } - } - - for (i = 0; i < num; i++) - { - if (group->meth != points[i]->meth) - { - ECerr(EC_F_EC_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS); - return 0; - } - } - - totalnum = num + (scalar != NULL); - - wsize = OPENSSL_malloc(totalnum * sizeof wsize[0]); - wbits = OPENSSL_malloc(totalnum * sizeof wbits[0]); - wpos = OPENSSL_malloc(totalnum * sizeof wpos[0]); - if (wsize == NULL || wbits == NULL || wpos == NULL) goto err; - - /* num_val := total number of points to precompute */ - num_val = 0; - for (i = 0; i < totalnum; i++) - { - size_t bits; - - bits = i < num ? BN_num_bits(scalars[i]) : BN_num_bits(scalar); - wsize[i] = EC_window_bits_for_scalar_size(bits); - num_val += 1u << (wsize[i] - 1); - if (bits > max_bits) - max_bits = bits; - wbits[i] = 0; - wpos[i] = 0; - } - - /* all precomputed points go into a single array 'val', - * 'val_sub[i]' is a pointer to the subarray for the i-th point */ - val = OPENSSL_malloc((num_val + 1) * sizeof val[0]); - if (val == NULL) goto err; - val[num_val] = NULL; /* pivot element */ - - val_sub = OPENSSL_malloc(totalnum * sizeof val_sub[0]); - if (val_sub == NULL) goto err; - - /* allocate points for precomputation */ - v = val; - for (i = 0; i < totalnum; i++) - { - val_sub[i] = v; - for (j = 0; j < (1u << (wsize[i] - 1)); j++) - { - *v = EC_POINT_new(group); - if (*v == NULL) goto err; - v++; - } - } - if (!(v == val + num_val)) - { - ECerr(EC_F_EC_POINTS_MUL, ERR_R_INTERNAL_ERROR); - goto err; - } - - if (ctx == NULL) - { - ctx = new_ctx = BN_CTX_new(); - if (ctx == NULL) - goto err; - } - - tmp = EC_POINT_new(group); - if (tmp == NULL) goto err; - - /* prepare precomputed values: - * val_sub[i][0] := points[i] - * val_sub[i][1] := 3 * points[i] - * val_sub[i][2] := 5 * points[i] - * ... - */ - for (i = 0; i < totalnum; i++) - { - if (i < num) - { - if (!EC_POINT_copy(val_sub[i][0], points[i])) goto err; - if (scalars[i]->neg) - { - if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err; - } - } - else - { - if (!EC_POINT_copy(val_sub[i][0], generator)) goto err; - if (scalar->neg) - { - if (!EC_POINT_invert(group, val_sub[i][0], ctx)) goto err; - } - } - - if (wsize[i] > 1) - { - if (!EC_POINT_dbl(group, tmp, val_sub[i][0], ctx)) goto err; - for (j = 1; j < (1u << (wsize[i] - 1)); j++) - { - if (!EC_POINT_add(group, val_sub[i][j], val_sub[i][j - 1], tmp, ctx)) goto err; - } - } - } - -#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ - if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err; -#endif - - r_is_at_infinity = 1; - - for (k = max_bits - 1; k >= 0; k--) - { - if (!r_is_at_infinity) - { - if (!EC_POINT_dbl(group, r, r, ctx)) goto err; - } - - for (i = 0; i < totalnum; i++) - { - if (wbits[i] == 0) - { - const BIGNUM *s; - - s = i < num ? scalars[i] : scalar; - - if (BN_is_bit_set(s, k)) - { - /* look at bits k - wsize[i] + 1 .. k for this window */ - t = k - wsize[i] + 1; - while (!BN_is_bit_set(s, t)) /* BN_is_bit_set is false for t < 0 */ - t++; - wpos[i] = t; - wbits[i] = 1; - for (t = k - 1; t >= wpos[i]; t--) - { - wbits[i] <<= 1; - if (BN_is_bit_set(s, t)) - wbits[i]++; - } - /* now wbits[i] is the odd bit pattern at bits wpos[i] .. k */ - } - } - - if ((wbits[i] != 0) && (wpos[i] == k)) - { - if (r_is_at_infinity) - { - if (!EC_POINT_copy(r, val_sub[i][wbits[i] >> 1])) goto err; - r_is_at_infinity = 0; - } - else - { - if (!EC_POINT_add(group, r, r, val_sub[i][wbits[i] >> 1], ctx)) goto err; - } - wbits[i] = 0; - } - } - } - - if (r_is_at_infinity) - if (!EC_POINT_set_to_infinity(group, r)) goto err; - - ret = 1; - - err: - if (new_ctx != NULL) - BN_CTX_free(new_ctx); - if (tmp != NULL) - EC_POINT_free(tmp); - if (wsize != NULL) - OPENSSL_free(wsize); - if (wbits != NULL) - OPENSSL_free(wbits); - if (wpos != NULL) - OPENSSL_free(wpos); - if (val != NULL) - { - for (v = val; *v != NULL; v++) - EC_POINT_clear_free(*v); - - OPENSSL_free(val); - } - if (val_sub != NULL) - { - OPENSSL_free(val_sub); - } - return ret; - } -#endif - int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar, const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx) {