Pieter Wuille
9 years ago
committed by
Jack Grigg
13 changed files with 296 additions and 403 deletions
@ -0,0 +1,20 @@ |
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(note: this is a temporary file, to be added-to by anybody, and moved to |
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release-notes at release time) |
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Notable changes |
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=============== |
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Signature validation using libsecp256k1 |
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--------------------------------------- |
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ECDSA signatures inside Zcash transactions now use validation using |
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[https://github.com/bitcoin/secp256k1](libsecp256k1) instead of OpenSSL. |
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Depending on the platform, this means a significant speedup for raw signature |
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validation speed. The advantage is largest on x86_64, where validation is over |
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five times faster. In practice, this translates to a raw reindexing and new |
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block validation times that are less than half of what it was before. |
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Libsecp256k1 has undergone very extensive testing and validation upstream. |
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A side effect of this change is that libconsensus no longer depends on OpenSSL. |
@ -1,68 +0,0 @@ |
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// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include "eccryptoverify.h" |
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namespace { |
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int CompareBigEndian(const unsigned char *c1, size_t c1len, const unsigned char *c2, size_t c2len) { |
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while (c1len > c2len) { |
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if (*c1) |
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return 1; |
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c1++; |
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c1len--; |
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} |
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while (c2len > c1len) { |
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if (*c2) |
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return -1; |
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c2++; |
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c2len--; |
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} |
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while (c1len > 0) { |
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if (*c1 > *c2) |
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return 1; |
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if (*c2 > *c1) |
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return -1; |
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c1++; |
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c2++; |
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c1len--; |
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} |
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return 0; |
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} |
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/** Order of secp256k1's generator minus 1. */ |
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const unsigned char vchMaxModOrder[32] = { |
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, |
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE, |
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0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B, |
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0xBF,0xD2,0x5E,0x8C,0xD0,0x36,0x41,0x40 |
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}; |
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/** Half of the order of secp256k1's generator minus 1. */ |
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const unsigned char vchMaxModHalfOrder[32] = { |
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0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, |
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, |
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0x5D,0x57,0x6E,0x73,0x57,0xA4,0x50,0x1D, |
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0xDF,0xE9,0x2F,0x46,0x68,0x1B,0x20,0xA0 |
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}; |
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const unsigned char vchZero[1] = {0}; |
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} // anon namespace
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namespace eccrypto { |
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bool Check(const unsigned char *vch) { |
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return vch && |
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CompareBigEndian(vch, 32, vchZero, 0) > 0 && |
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CompareBigEndian(vch, 32, vchMaxModOrder, 32) <= 0; |
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} |
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bool CheckSignatureElement(const unsigned char *vch, int len, bool half) { |
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return vch && |
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CompareBigEndian(vch, len, vchZero, 0) > 0 && |
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CompareBigEndian(vch, len, half ? vchMaxModHalfOrder : vchMaxModOrder, 32) <= 0; |
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} |
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} // namespace eccrypto
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@ -1,21 +0,0 @@ |
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// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_ECCRYPTOVERIFY_H |
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#define BITCOIN_ECCRYPTOVERIFY_H |
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#include <vector> |
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#include <cstdlib> |
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class uint256; |
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namespace eccrypto { |
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bool Check(const unsigned char *vch); |
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bool CheckSignatureElement(const unsigned char *vch, int len, bool half); |
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} // eccrypto namespace
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#endif // BITCOIN_ECCRYPTOVERIFY_H
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@ -1,223 +0,0 @@ |
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include "ecwrapper.h" |
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#include "serialize.h" |
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#include "uint256.h" |
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#include <openssl/bn.h> |
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#include <openssl/obj_mac.h> |
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namespace { |
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class ecgroup_order |
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{ |
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public: |
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static const EC_GROUP* get() |
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{ |
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static const ecgroup_order wrapper; |
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return wrapper.pgroup; |
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} |
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private: |
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ecgroup_order() |
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: pgroup(EC_GROUP_new_by_curve_name(NID_secp256k1)) |
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{ |
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} |
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~ecgroup_order() |
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{ |
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EC_GROUP_free(pgroup); |
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} |
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EC_GROUP* pgroup; |
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}; |
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/**
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* Perform ECDSA key recovery (see SEC1 4.1.6) for curves over (mod p)-fields |
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* recid selects which key is recovered |
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* if check is non-zero, additional checks are performed |
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*/ |
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int ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check) |
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{ |
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if (!eckey) return 0; |
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int ret = 0; |
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BN_CTX *ctx = NULL; |
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BIGNUM *x = NULL; |
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BIGNUM *e = NULL; |
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BIGNUM *order = NULL; |
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BIGNUM *sor = NULL; |
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BIGNUM *eor = NULL; |
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BIGNUM *field = NULL; |
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EC_POINT *R = NULL; |
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EC_POINT *O = NULL; |
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EC_POINT *Q = NULL; |
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BIGNUM *rr = NULL; |
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BIGNUM *zero = NULL; |
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int n = 0; |
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int i = recid / 2; |
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const BIGNUM *sig_r, *sig_s; |
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ECDSA_SIG_get0(ecsig, &sig_r, &sig_s); |
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const EC_GROUP *group = EC_KEY_get0_group(eckey); |
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if ((ctx = BN_CTX_new()) == NULL) { ret = -1; goto err; } |
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BN_CTX_start(ctx); |
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order = BN_CTX_get(ctx); |
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if (!EC_GROUP_get_order(group, order, ctx)) { ret = -2; goto err; } |
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x = BN_CTX_get(ctx); |
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if (!BN_copy(x, order)) { ret=-1; goto err; } |
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if (!BN_mul_word(x, i)) { ret=-1; goto err; } |
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if (!BN_add(x, x, sig_r)) { ret=-1; goto err; } |
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field = BN_CTX_get(ctx); |
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if (!EC_GROUP_get_curve_GFp(group, field, NULL, NULL, ctx)) { ret=-2; goto err; } |
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if (BN_cmp(x, field) >= 0) { ret=0; goto err; } |
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if ((R = EC_POINT_new(group)) == NULL) { ret = -2; goto err; } |
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if (!EC_POINT_set_compressed_coordinates_GFp(group, R, x, recid % 2, ctx)) { ret=0; goto err; } |
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if (check) |
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{ |
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if ((O = EC_POINT_new(group)) == NULL) { ret = -2; goto err; } |
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if (!EC_POINT_mul(group, O, NULL, R, order, ctx)) { ret=-2; goto err; } |
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if (!EC_POINT_is_at_infinity(group, O)) { ret = 0; goto err; } |
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} |
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if ((Q = EC_POINT_new(group)) == NULL) { ret = -2; goto err; } |
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n = EC_GROUP_get_degree(group); |
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e = BN_CTX_get(ctx); |
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if (!BN_bin2bn(msg, msglen, e)) { ret=-1; goto err; } |
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if (8*msglen > n) BN_rshift(e, e, 8-(n & 7)); |
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zero = BN_CTX_get(ctx); |
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if (!BN_zero(zero)) { ret=-1; goto err; } |
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if (!BN_mod_sub(e, zero, e, order, ctx)) { ret=-1; goto err; } |
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rr = BN_CTX_get(ctx); |
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if (!BN_mod_inverse(rr, sig_r, order, ctx)) { ret=-1; goto err; } |
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sor = BN_CTX_get(ctx); |
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if (!BN_mod_mul(sor, sig_s, rr, order, ctx)) { ret=-1; goto err; } |
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eor = BN_CTX_get(ctx); |
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if (!BN_mod_mul(eor, e, rr, order, ctx)) { ret=-1; goto err; } |
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if (!EC_POINT_mul(group, Q, eor, R, sor, ctx)) { ret=-2; goto err; } |
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if (!EC_KEY_set_public_key(eckey, Q)) { ret=-2; goto err; } |
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ret = 1; |
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err: |
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if (ctx) { |
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BN_CTX_end(ctx); |
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BN_CTX_free(ctx); |
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} |
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if (R != NULL) EC_POINT_free(R); |
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if (O != NULL) EC_POINT_free(O); |
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if (Q != NULL) EC_POINT_free(Q); |
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return ret; |
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} |
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} // anon namespace
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CECKey::CECKey() { |
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pkey = EC_KEY_new(); |
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assert(pkey != NULL); |
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int result = EC_KEY_set_group(pkey, ecgroup_order::get()); |
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assert(result); |
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} |
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CECKey::~CECKey() { |
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EC_KEY_free(pkey); |
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} |
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void CECKey::GetPubKey(std::vector<unsigned char> &pubkey, bool fCompressed) { |
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EC_KEY_set_conv_form(pkey, fCompressed ? POINT_CONVERSION_COMPRESSED : POINT_CONVERSION_UNCOMPRESSED); |
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int nSize = i2o_ECPublicKey(pkey, NULL); |
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assert(nSize); |
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assert(nSize <= 65); |
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pubkey.clear(); |
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pubkey.resize(nSize); |
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unsigned char *pbegin(begin_ptr(pubkey)); |
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int nSize2 = i2o_ECPublicKey(pkey, &pbegin); |
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assert(nSize == nSize2); |
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} |
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bool CECKey::SetPubKey(const unsigned char* pubkey, size_t size) { |
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return o2i_ECPublicKey(&pkey, &pubkey, size) != NULL; |
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} |
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bool CECKey::Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig) { |
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if (vchSig.empty()) |
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return false; |
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// New versions of OpenSSL will reject non-canonical DER signatures. de/re-serialize first.
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unsigned char *norm_der = NULL; |
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ECDSA_SIG *norm_sig = ECDSA_SIG_new(); |
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const unsigned char* sigptr = &vchSig[0]; |
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assert(norm_sig); |
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if (d2i_ECDSA_SIG(&norm_sig, &sigptr, vchSig.size()) == NULL) |
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{ |
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/* As of OpenSSL 1.0.0p d2i_ECDSA_SIG frees and nulls the pointer on
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* error. But OpenSSL's own use of this function redundantly frees the |
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* result. As ECDSA_SIG_free(NULL) is a no-op, and in the absence of a |
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* clear contract for the function behaving the same way is more |
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* conservative. |
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*/ |
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ECDSA_SIG_free(norm_sig); |
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return false; |
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} |
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int derlen = i2d_ECDSA_SIG(norm_sig, &norm_der); |
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ECDSA_SIG_free(norm_sig); |
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if (derlen <= 0) |
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return false; |
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// -1 = error, 0 = bad sig, 1 = good
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bool ret = ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), norm_der, derlen, pkey) == 1; |
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OPENSSL_free(norm_der); |
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return ret; |
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} |
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bool CECKey::Recover(const uint256 &hash, const unsigned char *p64, int rec) |
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{ |
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if (rec<0 || rec>=3) |
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return false; |
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ECDSA_SIG *sig = ECDSA_SIG_new(); |
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BIGNUM *sig_r = BN_bin2bn(&p64[0], 32, nullptr); |
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BIGNUM *sig_s = BN_bin2bn(&p64[32], 32, nullptr); |
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assert(sig && sig_r && sig_s); |
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bool ret = ECDSA_SIG_set0(sig, sig_r, sig_s); |
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assert(ret); |
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ret = ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), rec, 0) == 1; |
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ECDSA_SIG_free(sig); |
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return ret; |
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} |
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bool CECKey::TweakPublic(const unsigned char vchTweak[32]) { |
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bool ret = true; |
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BN_CTX *ctx = BN_CTX_new(); |
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BN_CTX_start(ctx); |
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BIGNUM *bnTweak = BN_CTX_get(ctx); |
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BIGNUM *bnOrder = BN_CTX_get(ctx); |
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BIGNUM *bnOne = BN_CTX_get(ctx); |
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const EC_GROUP *group = EC_KEY_get0_group(pkey); |
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EC_GROUP_get_order(group, bnOrder, ctx); // what a grossly inefficient way to get the (constant) group order...
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BN_bin2bn(vchTweak, 32, bnTweak); |
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if (BN_cmp(bnTweak, bnOrder) >= 0) |
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ret = false; // extremely unlikely
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EC_POINT *point = EC_POINT_dup(EC_KEY_get0_public_key(pkey), group); |
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BN_one(bnOne); |
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EC_POINT_mul(group, point, bnTweak, point, bnOne, ctx); |
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if (EC_POINT_is_at_infinity(group, point)) |
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ret = false; // ridiculously unlikely
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EC_KEY_set_public_key(pkey, point); |
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EC_POINT_free(point); |
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BN_CTX_end(ctx); |
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BN_CTX_free(ctx); |
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return ret; |
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} |
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bool CECKey::SanityCheck() |
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{ |
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const EC_GROUP *pgroup = ecgroup_order::get(); |
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if(pgroup == NULL) |
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return false; |
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// TODO Is there more EC functionality that could be missing?
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return true; |
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} |
@ -1,40 +0,0 @@ |
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_ECWRAPPER_H |
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#define BITCOIN_ECWRAPPER_H |
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#include <cstddef> |
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#include <vector> |
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#include <openssl/ec.h> |
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class uint256; |
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/** RAII Wrapper around OpenSSL's EC_KEY */ |
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class CECKey { |
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private: |
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EC_KEY *pkey; |
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public: |
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CECKey(); |
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~CECKey(); |
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void GetPubKey(std::vector<unsigned char>& pubkey, bool fCompressed); |
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bool SetPubKey(const unsigned char* pubkey, size_t size); |
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bool Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig); |
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/**
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* reconstruct public key from a compact signature |
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* This is only slightly more CPU intensive than just verifying it. |
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* If this function succeeds, the recovered public key is guaranteed to be valid |
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* (the signature is a valid signature of the given data for that key) |
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*/ |
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bool Recover(const uint256 &hash, const unsigned char *p64, int rec); |
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bool TweakPublic(const unsigned char vchTweak[32]); |
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static bool SanityCheck(); |
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}; |
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#endif // BITCOIN_ECWRAPPER_H
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