323 lines
12 KiB
C++
323 lines
12 KiB
C++
// Copyright (c) 2009-2016 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 "key.h"
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#include "arith_uint256.h"
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#include "crypto/common.h"
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#include "crypto/hmac_sha512.h"
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#include "pubkey.h"
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#include "random.h"
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#include <secp256k1.h>
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#include <secp256k1_recovery.h>
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static secp256k1_context* secp256k1_context_sign = NULL;
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/** These functions are taken from the libsecp256k1 distribution and are very ugly. */
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static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen) {
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const unsigned char *end = privkey + privkeylen;
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int lenb = 0;
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int len = 0;
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memset(out32, 0, 32);
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/* sequence header */
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if (end < privkey+1 || *privkey != 0x30) {
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return 0;
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}
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privkey++;
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/* sequence length constructor */
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if (end < privkey+1 || !(*privkey & 0x80)) {
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return 0;
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}
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lenb = *privkey & ~0x80; privkey++;
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if (lenb < 1 || lenb > 2) {
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return 0;
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}
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if (end < privkey+lenb) {
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return 0;
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}
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/* sequence length */
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len = privkey[lenb-1] | (lenb > 1 ? privkey[lenb-2] << 8 : 0);
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privkey += lenb;
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if (end < privkey+len) {
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return 0;
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}
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/* sequence element 0: version number (=1) */
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if (end < privkey+3 || privkey[0] != 0x02 || privkey[1] != 0x01 || privkey[2] != 0x01) {
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return 0;
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}
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privkey += 3;
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/* sequence element 1: octet string, up to 32 bytes */
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if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1]) {
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return 0;
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}
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memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
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if (!secp256k1_ec_seckey_verify(ctx, out32)) {
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memset(out32, 0, 32);
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return 0;
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}
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return 1;
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}
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static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
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secp256k1_pubkey pubkey;
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size_t pubkeylen = 0;
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if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
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*privkeylen = 0;
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return 0;
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}
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if (compressed) {
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static const unsigned char begin[] = {
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0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
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};
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static const unsigned char middle[] = {
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0xA0,0x81,0x85,0x30,0x81,0x82,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
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0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
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0x21,0x02,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
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0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
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0x17,0x98,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
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0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x24,0x03,0x22,0x00
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};
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unsigned char *ptr = privkey;
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memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
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memcpy(ptr, key32, 32); ptr += 32;
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memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
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pubkeylen = 33;
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secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
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ptr += pubkeylen;
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*privkeylen = ptr - privkey;
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} else {
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static const unsigned char begin[] = {
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0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
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};
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static const unsigned char middle[] = {
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0xA0,0x81,0xA5,0x30,0x81,0xA2,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
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0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
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0x41,0x04,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
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0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
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0x17,0x98,0x48,0x3A,0xDA,0x77,0x26,0xA3,0xC4,0x65,0x5D,0xA4,0xFB,0xFC,0x0E,0x11,
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0x08,0xA8,0xFD,0x17,0xB4,0x48,0xA6,0x85,0x54,0x19,0x9C,0x47,0xD0,0x8F,0xFB,0x10,
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0xD4,0xB8,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
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0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
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0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x44,0x03,0x42,0x00
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};
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unsigned char *ptr = privkey;
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memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
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memcpy(ptr, key32, 32); ptr += 32;
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memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
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pubkeylen = 65;
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secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
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ptr += pubkeylen;
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*privkeylen = ptr - privkey;
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}
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return 1;
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}
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bool CKey::Check(const unsigned char *vch) {
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return secp256k1_ec_seckey_verify(secp256k1_context_sign, vch);
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}
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void CKey::MakeNewKey(bool fCompressedIn) {
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do {
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GetStrongRandBytes(keydata.data(), keydata.size());
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} while (!Check(keydata.data()));
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fValid = true;
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fCompressed = fCompressedIn;
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}
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bool CKey::SetPrivKey(const CPrivKey &privkey, bool fCompressedIn) {
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if (!ec_privkey_import_der(secp256k1_context_sign, (unsigned char*)begin(), &privkey[0], privkey.size()))
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return false;
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fCompressed = fCompressedIn;
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fValid = true;
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return true;
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}
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CPrivKey CKey::GetPrivKey() const {
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assert(fValid);
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CPrivKey privkey;
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int ret;
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size_t privkeylen;
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privkey.resize(279);
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privkeylen = 279;
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ret = ec_privkey_export_der(secp256k1_context_sign, (unsigned char*)&privkey[0], &privkeylen, begin(), fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
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assert(ret);
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privkey.resize(privkeylen);
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return privkey;
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}
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CPubKey CKey::GetPubKey() const {
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assert(fValid);
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secp256k1_pubkey pubkey;
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size_t clen = 65;
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CPubKey result;
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int ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
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assert(ret);
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secp256k1_ec_pubkey_serialize(secp256k1_context_sign, (unsigned char*)result.begin(), &clen, &pubkey, fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
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assert(result.size() == clen);
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assert(result.IsValid());
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return result;
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}
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bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
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if (!fValid)
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return false;
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vchSig.resize(72);
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size_t nSigLen = 72;
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unsigned char extra_entropy[32] = {0};
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WriteLE32(extra_entropy, test_case);
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secp256k1_ecdsa_signature sig;
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int ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, test_case ? extra_entropy : NULL);
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assert(ret);
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secp256k1_ecdsa_signature_serialize_der(secp256k1_context_sign, (unsigned char*)&vchSig[0], &nSigLen, &sig);
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vchSig.resize(nSigLen);
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return true;
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}
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bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
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if (pubkey.IsCompressed() != fCompressed) {
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return false;
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}
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unsigned char rnd[8];
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std::string str = "Bitcoin key verification\n";
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GetRandBytes(rnd, sizeof(rnd));
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uint256 hash;
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CHash256().Write((unsigned char*)str.data(), str.size()).Write(rnd, sizeof(rnd)).Finalize(hash.begin());
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std::vector<unsigned char> vchSig;
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Sign(hash, vchSig);
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return pubkey.Verify(hash, vchSig);
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}
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bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
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if (!fValid)
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return false;
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vchSig.resize(65);
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int rec = -1;
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secp256k1_ecdsa_recoverable_signature sig;
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int ret = secp256k1_ecdsa_sign_recoverable(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, NULL);
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assert(ret);
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secp256k1_ecdsa_recoverable_signature_serialize_compact(secp256k1_context_sign, (unsigned char*)&vchSig[1], &rec, &sig);
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assert(ret);
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assert(rec != -1);
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vchSig[0] = 27 + rec + (fCompressed ? 4 : 0);
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return true;
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}
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bool CKey::Load(CPrivKey &privkey, CPubKey &vchPubKey, bool fSkipCheck=false) {
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if (!ec_privkey_import_der(secp256k1_context_sign, (unsigned char*)begin(), &privkey[0], privkey.size()))
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return false;
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fCompressed = vchPubKey.IsCompressed();
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fValid = true;
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if (fSkipCheck)
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return true;
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return VerifyPubKey(vchPubKey);
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}
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bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const {
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assert(IsValid());
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assert(IsCompressed());
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std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
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if ((nChild >> 31) == 0) {
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CPubKey pubkey = GetPubKey();
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assert(pubkey.begin() + 33 == pubkey.end());
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BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, vout.data());
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} else {
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assert(begin() + 32 == end());
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BIP32Hash(cc, nChild, 0, begin(), vout.data());
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}
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memcpy(ccChild.begin(), vout.data()+32, 32);
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memcpy((unsigned char*)keyChild.begin(), begin(), 32);
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bool ret = secp256k1_ec_privkey_tweak_add(secp256k1_context_sign, (unsigned char*)keyChild.begin(), vout.data());
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keyChild.fCompressed = true;
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keyChild.fValid = ret;
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return ret;
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}
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bool CExtKey::Derive(CExtKey &out, unsigned int _nChild) const {
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out.nDepth = nDepth + 1;
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CKeyID id = key.GetPubKey().GetID();
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memcpy(&out.vchFingerprint[0], &id, 4);
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out.nChild = _nChild;
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return key.Derive(out.key, out.chaincode, _nChild, chaincode);
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}
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void CExtKey::SetMaster(const unsigned char *seed, unsigned int nSeedLen) {
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static const unsigned char hashkey[] = {'B','i','t','c','o','i','n',' ','s','e','e','d'};
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std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
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CHMAC_SHA512(hashkey, sizeof(hashkey)).Write(seed, nSeedLen).Finalize(vout.data());
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key.Set(&vout[0], &vout[32], true);
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memcpy(chaincode.begin(), &vout[32], 32);
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nDepth = 0;
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nChild = 0;
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memset(vchFingerprint, 0, sizeof(vchFingerprint));
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}
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CExtPubKey CExtKey::Neuter() const {
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CExtPubKey ret;
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ret.nDepth = nDepth;
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memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
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ret.nChild = nChild;
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ret.pubkey = key.GetPubKey();
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ret.chaincode = chaincode;
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return ret;
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}
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void CExtKey::Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const {
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code[0] = nDepth;
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memcpy(code+1, vchFingerprint, 4);
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code[5] = (nChild >> 24) & 0xFF; code[6] = (nChild >> 16) & 0xFF;
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code[7] = (nChild >> 8) & 0xFF; code[8] = (nChild >> 0) & 0xFF;
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memcpy(code+9, chaincode.begin(), 32);
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code[41] = 0;
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assert(key.size() == 32);
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memcpy(code+42, key.begin(), 32);
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}
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void CExtKey::Decode(const unsigned char code[BIP32_EXTKEY_SIZE]) {
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nDepth = code[0];
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memcpy(vchFingerprint, code+1, 4);
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nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
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memcpy(chaincode.begin(), code+9, 32);
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key.Set(code+42, code+BIP32_EXTKEY_SIZE, true);
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}
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bool ECC_InitSanityCheck() {
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CKey key;
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key.MakeNewKey(true);
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CPubKey pubkey = key.GetPubKey();
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return key.VerifyPubKey(pubkey);
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}
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void ECC_Start() {
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assert(secp256k1_context_sign == NULL);
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secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
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assert(ctx != NULL);
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{
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// Pass in a random blinding seed to the secp256k1 context.
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std::vector<unsigned char, secure_allocator<unsigned char>> vseed(32);
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GetRandBytes(vseed.data(), 32);
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bool ret = secp256k1_context_randomize(ctx, vseed.data());
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assert(ret);
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}
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secp256k1_context_sign = ctx;
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}
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void ECC_Stop() {
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secp256k1_context *ctx = secp256k1_context_sign;
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secp256k1_context_sign = NULL;
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if (ctx) {
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secp256k1_context_destroy(ctx);
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}
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}
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