| File: | lib/nettle/ecc_map.c |
| Location: | line 48, column 8 |
| Description: | Although the value stored to 'err' is used in the enclosing expression, the value is never actually read from 'err' |
| 1 | /* |
| 2 | * Copyright (C) 2011-2012 Free Software Foundation, Inc. |
| 3 | * |
| 4 | * This file is part of GNUTLS. |
| 5 | * |
| 6 | * The GNUTLS library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public License |
| 8 | * as published by the Free Software Foundation; either version 3 of |
| 9 | * the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, but |
| 12 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public License |
| 17 | * along with this program. If not, see <http://www.gnu.org/licenses/> |
| 18 | * |
| 19 | */ |
| 20 | |
| 21 | /* Based on public domain code of LibTomCrypt by Tom St Denis. |
| 22 | * Adapted to gmp and nettle by Nikos Mavrogiannopoulos. |
| 23 | */ |
| 24 | |
| 25 | #include "ecc.h" |
| 26 | |
| 27 | /* |
| 28 | @file ecc_map.c |
| 29 | ECC Crypto, Tom St Denis |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | Map a projective jacobian point back to affine space |
| 34 | @param P [in/out] The point to map |
| 35 | @param modulus The modulus of the field the ECC curve is in |
| 36 | @param mp The "b" value from montgomery_setup() |
| 37 | @return 0 on success |
| 38 | */ |
| 39 | int |
| 40 | ecc_map (ecc_point * P, mpz_t modulus) |
| 41 | { |
| 42 | mpz_t t1, t2; |
| 43 | int err; |
| 44 | |
| 45 | if (P == NULL((void*)0)) |
| 46 | return -1; |
| 47 | |
| 48 | if ((err = mp_init_multi (&t1, &t2, NULL((void*)0))) != 0) |
Although the value stored to 'err' is used in the enclosing expression, the value is never actually read from 'err' | |
| 49 | { |
| 50 | return -1; |
| 51 | } |
| 52 | |
| 53 | mpz_mod__gmpz_mod (P->z, P->z, modulus); |
| 54 | |
| 55 | /* get 1/z */ |
| 56 | mpz_invert__gmpz_invert (t1, P->z, modulus); |
| 57 | |
| 58 | /* get 1/z^2 and 1/z^3 */ |
| 59 | mpz_mul__gmpz_mul (t2, t1, t1); |
| 60 | mpz_mod__gmpz_mod (t2, t2, modulus); |
| 61 | mpz_mul__gmpz_mul (t1, t1, t2); |
| 62 | mpz_mod__gmpz_mod (t1, t1, modulus); |
| 63 | |
| 64 | /* multiply against x/y */ |
| 65 | mpz_mul__gmpz_mul (P->x, P->x, t2); |
| 66 | mpz_mod__gmpz_mod (P->x, P->x, modulus); |
| 67 | mpz_mul__gmpz_mul (P->y, P->y, t1); |
| 68 | mpz_mod__gmpz_mod (P->y, P->y, modulus); |
| 69 | mpz_set_ui__gmpz_set_ui (P->z, 1); |
| 70 | |
| 71 | err = 0; |
| 72 | |
| 73 | mp_clear_multi (&t1, &t2, NULL((void*)0)); |
| 74 | return err; |
| 75 | } |
| 76 | |
| 77 | /* $Source: /webcvs/gnutls/gnutls/clang/report-4lXRsy.html,v $ */ |
| 78 | /* $Revision: 1.1 $ */ |
| 79 | /* $Date: 2012/01/20 14:01:22 $ */ |