1 /* 2 * Copyright 2014-2018 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #ifndef OSSL_CRYPTO_BN_H 11 # define OSSL_CRYPTO_BN_H 12 13 # include <openssl/bn.h> 14 # include <limits.h> 15 16 BIGNUM *bn_wexpand(BIGNUM *a, int words); 17 BIGNUM *bn_expand2(BIGNUM *a, int words); 18 19 void bn_correct_top(BIGNUM *a); 20 21 /* 22 * Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'. 23 * This is an array r[] of values that are either zero or odd with an 24 * absolute value less than 2^w satisfying scalar = \sum_j r[j]*2^j where at 25 * most one of any w+1 consecutive digits is non-zero with the exception that 26 * the most significant digit may be only w-1 zeros away from that next 27 * non-zero digit. 28 */ 29 signed char *bn_compute_wNAF(const BIGNUM *scalar, int w, size_t *ret_len); 30 31 int bn_get_top(const BIGNUM *a); 32 33 int bn_get_dmax(const BIGNUM *a); 34 35 /* Set all words to zero */ 36 void bn_set_all_zero(BIGNUM *a); 37 38 /* 39 * Copy the internal BIGNUM words into out which holds size elements (and size 40 * must be bigger than top) 41 */ 42 int bn_copy_words(BN_ULONG *out, const BIGNUM *in, int size); 43 44 BN_ULONG *bn_get_words(const BIGNUM *a); 45 46 /* 47 * Set the internal data words in a to point to words which contains size 48 * elements. The BN_FLG_STATIC_DATA flag is set 49 */ 50 void bn_set_static_words(BIGNUM *a, const BN_ULONG *words, int size); 51 52 /* 53 * Copy words into the BIGNUM |a|, reallocating space as necessary. 54 * The negative flag of |a| is not modified. 55 * Returns 1 on success and 0 on failure. 56 */ 57 /* 58 * |num_words| is int because bn_expand2 takes an int. This is an internal 59 * function so we simply trust callers not to pass negative values. 60 */ 61 int bn_set_words(BIGNUM *a, const BN_ULONG *words, int num_words); 62 63 /* 64 * Some BIGNUM functions assume most significant limb to be non-zero, which 65 * is customarily arranged by bn_correct_top. Output from below functions 66 * is not processed with bn_correct_top, and for this reason it may not be 67 * returned out of public API. It may only be passed internally into other 68 * functions known to support non-minimal or zero-padded BIGNUMs. Even 69 * though the goal is to facilitate constant-time-ness, not each subroutine 70 * is constant-time by itself. They all have pre-conditions, consult source 71 * code... 72 */ 73 int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, 74 BN_MONT_CTX *mont, BN_CTX *ctx); 75 int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, 76 BN_CTX *ctx); 77 int bn_from_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, 78 BN_CTX *ctx); 79 int bn_mod_add_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, 80 const BIGNUM *m); 81 int bn_mod_sub_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, 82 const BIGNUM *m); 83 int bn_mul_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx); 84 int bn_sqr_fixed_top(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx); 85 int bn_lshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n); 86 int bn_rshift_fixed_top(BIGNUM *r, const BIGNUM *a, int n); 87 int bn_div_fixed_top(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, 88 const BIGNUM *d, BN_CTX *ctx); 89 int ossl_bn_rsa_do_unblind(const BIGNUM *intermediate, 90 const BN_BLINDING *blinding, 91 const BIGNUM *possible_arg2, 92 const BIGNUM *to_mod, BN_CTX *ctx, 93 unsigned char *buf, int num); 94 95 #endif 96