| /* curve25519.c |
| * |
| * Copyright (C) 2006-2015 wolfSSL Inc. |
| * |
| * This file is part of wolfSSL. (formerly known as CyaSSL) |
| * |
| * wolfSSL is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * wolfSSL is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA |
| */ |
| |
| /* Based On Daniel J Bernstein's curve25519 Public Domain ref10 work. */ |
| |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif |
| |
| #include <wolfssl/wolfcrypt/settings.h> |
| |
| #ifdef HAVE_CURVE25519 |
| |
| #include <wolfssl/wolfcrypt/curve25519.h> |
| #include <wolfssl/wolfcrypt/error-crypt.h> |
| #ifdef NO_INLINE |
| #include <wolfssl/wolfcrypt/misc.h> |
| #else |
| #include <wolfcrypt/src/misc.c> |
| #endif |
| |
| const curve25519_set_type curve25519_sets[] = { |
| { |
| 32, |
| "CURVE25519", |
| } |
| }; |
| |
| |
| |
| int wc_curve25519_make_key(RNG* rng, int keysize, curve25519_key* key) |
| { |
| unsigned char basepoint[CURVE25519_KEYSIZE] = {9}; |
| unsigned char n[CURVE25519_KEYSIZE]; |
| unsigned char p[CURVE25519_KEYSIZE]; |
| int i; |
| int ret; |
| |
| if (key == NULL || rng == NULL) |
| return ECC_BAD_ARG_E; |
| |
| /* currently only a key size of 32 bytes is used */ |
| if (keysize != CURVE25519_KEYSIZE) |
| return ECC_BAD_ARG_E; |
| |
| /* get random number from RNG */ |
| ret = wc_RNG_GenerateBlock(rng, n, keysize); |
| if (ret != 0) |
| return ret; |
| |
| for (i = 0; i < keysize; ++i) key->k.point[i] = n[i]; |
| key->k.point[ 0] &= 248; |
| key->k.point[31] &= 127; |
| key->k.point[31] |= 64; |
| |
| /* compute public key */ |
| ret = curve25519(p, key->k.point, basepoint); |
| |
| /* store keys in big endian format */ |
| for (i = 0; i < keysize; ++i) n[i] = key->k.point[i]; |
| for (i = 0; i < keysize; ++i) { |
| key->p.point[keysize - i - 1] = p[i]; |
| key->k.point[keysize - i - 1] = n[i]; |
| } |
| |
| ForceZero(n, keysize); |
| ForceZero(p, keysize); |
| |
| return ret; |
| } |
| |
| |
| int wc_curve25519_shared_secret(curve25519_key* private_key, |
| curve25519_key* public_key, |
| byte* out, word32* outlen) |
| { |
| unsigned char k[CURVE25519_KEYSIZE]; |
| unsigned char p[CURVE25519_KEYSIZE]; |
| unsigned char o[CURVE25519_KEYSIZE]; |
| int ret = 0; |
| int i; |
| |
| /* sanity check */ |
| if (private_key == NULL || public_key == NULL || out == NULL || |
| outlen == NULL) |
| return BAD_FUNC_ARG; |
| |
| /* avoid implementation fingerprinting */ |
| if (public_key->p.point[0] > 0x7F) |
| return ECC_BAD_ARG_E; |
| |
| XMEMSET(p, 0, sizeof(p)); |
| XMEMSET(k, 0, sizeof(k)); |
| XMEMSET(out, 0, CURVE25519_KEYSIZE); |
| |
| for (i = 0; i < CURVE25519_KEYSIZE; ++i) { |
| p[i] = public_key->p.point [CURVE25519_KEYSIZE - i - 1]; |
| k[i] = private_key->k.point[CURVE25519_KEYSIZE - i - 1]; |
| } |
| |
| ret = curve25519(o , k, p); |
| *outlen = CURVE25519_KEYSIZE; |
| |
| for (i = 0; i < CURVE25519_KEYSIZE; ++i) { |
| out[i] = o[CURVE25519_KEYSIZE - i -1]; |
| } |
| |
| ForceZero(p, sizeof(p)); |
| ForceZero(k, sizeof(k)); |
| ForceZero(o, sizeof(o)); |
| |
| return ret; |
| } |
| |
| |
| /* curve25519 uses a serialized string for key representation */ |
| int wc_curve25519_export_public(curve25519_key* key, byte* out, word32* outLen) |
| { |
| word32 keySz; |
| |
| if (key == NULL || out == NULL || outLen == NULL) |
| return BAD_FUNC_ARG; |
| |
| /* check size of outgoing key */ |
| keySz = wc_curve25519_size(key); |
| |
| /* copy in public key */ |
| XMEMCPY(out, key->p.point, keySz); |
| *outLen = keySz; |
| |
| return 0; |
| } |
| |
| /* import curve25519 public key |
| return 0 on success */ |
| int wc_curve25519_import_public(const byte* in, word32 inLen, |
| curve25519_key* key) |
| { |
| word32 keySz; |
| |
| /* sanity check */ |
| if (key == NULL || in == NULL) |
| return ECC_BAD_ARG_E; |
| |
| /* check size of incoming keys */ |
| keySz = wc_curve25519_size(key); |
| if (inLen != keySz) |
| return ECC_BAD_ARG_E; |
| |
| XMEMCPY(key->p.point, in, inLen); |
| |
| key->dp = &curve25519_sets[0]; |
| |
| return 0; |
| } |
| |
| |
| /* export curve25519 private key only raw, outLen is in/out size |
| return 0 on success */ |
| int wc_curve25519_export_private_raw(curve25519_key* key, byte* out, |
| word32* outLen) |
| { |
| word32 keySz; |
| |
| /* sanity check */ |
| if (key == NULL || out == NULL || outLen == NULL) |
| return ECC_BAD_ARG_E; |
| |
| keySz = wc_curve25519_size(key); |
| *outLen = keySz; |
| XMEMSET(out, 0, keySz); |
| XMEMCPY(out, key->k.point, keySz); |
| |
| return 0; |
| } |
| |
| |
| /* curve25519 private key import. |
| Public key to match private key needs to be imported too */ |
| int wc_curve25519_import_private_raw(const byte* priv, word32 privSz, |
| const byte* pub, word32 pubSz, curve25519_key* key) |
| { |
| int ret = 0; |
| word32 keySz; |
| |
| /* sanity check */ |
| if (key == NULL || priv == NULL || pub == NULL) |
| return ECC_BAD_ARG_E; |
| |
| /* check size of incoming keys */ |
| keySz = wc_curve25519_size(key); |
| if (privSz != keySz || pubSz != keySz) |
| return ECC_BAD_ARG_E; |
| |
| XMEMCPY(key->k.point, priv, privSz); |
| XMEMCPY(key->p.point, pub, pubSz); |
| |
| return ret; |
| } |
| |
| |
| int wc_curve25519_init(curve25519_key* key) |
| { |
| word32 keySz; |
| |
| if (key == NULL) |
| return ECC_BAD_ARG_E; |
| |
| /* currently the format for curve25519 */ |
| key->dp = &curve25519_sets[0]; |
| keySz = key->dp->size; |
| |
| XMEMSET(key->k.point, 0, keySz); |
| XMEMSET(key->p.point, 0, keySz); |
| |
| return 0; |
| } |
| |
| |
| /* Clean the memory of a key */ |
| void wc_curve25519_free(curve25519_key* key) |
| { |
| if (key == NULL) |
| return; |
| |
| key->dp = NULL; |
| ForceZero(key->p.point, sizeof(key->p.point)); |
| ForceZero(key->k.point, sizeof(key->k.point)); |
| } |
| |
| |
| /* get key size */ |
| int wc_curve25519_size(curve25519_key* key) |
| { |
| if (key == NULL) return 0; |
| |
| return key->dp->size; |
| } |
| |
| #endif /*HAVE_CURVE25519*/ |
| |