dash/src/key.cpp
fanquake 9d36ba6570
Merge #19228: Update libsecp256k1 subtree
e10439ce5a54cd13062e4ed07ebc681e385ed5cb scripted-diff: rename privkey with seckey in secp256k1 interface (Pieter Wuille)
ca8bc4233059bb576c658d1b20bbfbfc00e8481f Drop --disable-jni from libsecp256k1 configure options (Pieter Wuille)
ddc2419c090b0af65edc9eb07ac0a736eb351b69 Update MSVC build config for libsecp256k1 (Pieter Wuille)
67f232b5d874b501c114bced5d764db7f4f5ce99 Squashed 'src/secp256k1/' changes from b19c000063..2ed54da18a (Pieter Wuille)

Pull request description:

  It's been abound a year since the subtree was updated.

  Here is a list of the included PRs:

  * bitcoin-core/secp256k1#755: Recovery signing: add to constant time test, and eliminate non ct operators
  * bitcoin-core/secp256k1#754: Fix uninit values passed into cmov
  * bitcoin-core/secp256k1#752: autoconf: Use ":" instead of "dnl" as a noop
  * bitcoin-core/secp256k1#750: Add macOS to the CI
  * bitcoin-core/secp256k1#701: Make ec_ arithmetic more consistent and add documentation
  * bitcoin-core/secp256k1#732: Retry if r is zero during signing
  * bitcoin-core/secp256k1#742: Fix typo in ecmult_const_impl.h
  * bitcoin-core/secp256k1#740: Make recovery/main_impl.h non-executable
  * bitcoin-core/secp256k1#735: build: fix OpenSSL EC detection on macOS
  * bitcoin-core/secp256k1#728: Suppress a harmless variable-time optimization by clang in memczero
  * bitcoin-core/secp256k1#722: Context isn't freed in the ECDH benchmark
  * bitcoin-core/secp256k1#700: Allow overriding default flags
  * bitcoin-core/secp256k1#708: Constant-time behaviour test using valgrind memtest.
  * bitcoin-core/secp256k1#710: Eliminate harmless non-constant time operations on secret data.
  * bitcoin-core/secp256k1#718: Clarify that a secp256k1_ecdh_hash_function must return 0 or 1
  * bitcoin-core/secp256k1#714: doc: document the length requirements of output parameter.
  * bitcoin-core/secp256k1#682: Remove Java Native Interface
  * bitcoin-core/secp256k1#713: Docstrings
  * bitcoin-core/secp256k1#704: README: add a section for test coverage
  * bitcoin-core/secp256k1#709: Remove secret-dependant non-constant time operation in ecmult_const.
  * bitcoin-core/secp256k1#703: Overhaul README.md
  * bitcoin-core/secp256k1#689: Remove "except in benchmarks" exception for fp math
  * bitcoin-core/secp256k1#679: Add SECURITY.md
  * bitcoin-core/secp256k1#685: Fix issue where travis does not show the ./tests seed…
  * bitcoin-core/secp256k1#690: Add valgrind check to travis
  * bitcoin-core/secp256k1#678: Preventing compiler optimizations in benchmarks without a memory fence
  * bitcoin-core/secp256k1#688: Fix ASM setting in travis
  * bitcoin-core/secp256k1#684: Make no-float policy explicit
  * bitcoin-core/secp256k1#677: Remove note about heap allocation in secp256k1_ecmult_odd_multiples_table_storage_var
  * bitcoin-core/secp256k1#647: Increase robustness against UB in secp256k1_scalar_cadd_bit
  * bitcoin-core/secp256k1#664: Remove mention of ec_privkey_export because it doesn't exist
  * bitcoin-core/secp256k1#337: variable sized precomputed table for signing
  * bitcoin-core/secp256k1#661: Make ./configure string consistent
  * bitcoin-core/secp256k1#657: Fix a nit in the recovery tests
  * bitcoin-core/secp256k1#650: secp256k1/src/tests.c:  Properly handle sscanf return value
  * bitcoin-core/secp256k1#654: Fix typo (∞)
  * bitcoin-core/secp256k1#583: JNI: fix use sig array
  * bitcoin-core/secp256k1#644: Avoid optimizing out a verify_check
  * bitcoin-core/secp256k1#652: README.md: update instruction to run tests
  * bitcoin-core/secp256k1#651: Fix typo in secp256k1_preallocated.h
  * bitcoin-core/secp256k1#640: scalar_impl.h: fix includes
  * bitcoin-core/secp256k1#655: jni: Use only Guava for hex encoding and decoding
  * bitcoin-core/secp256k1#634: Add a descriptive comment for secp256k1_ecmult_const.
  * bitcoin-core/secp256k1#631: typo in comment for secp256k1_ec_pubkey_tweak_mul ()
  * bitcoin-core/secp256k1#629: Avoid calling _is_zero when _set_b32 fails.
  * bitcoin-core/secp256k1#630: Note intention of timing sidechannel freeness.
  * bitcoin-core/secp256k1#628: Fix ability to compile tests without -DVERIFY.
  * bitcoin-core/secp256k1#627: Guard memcmp in tests against mixed size inputs.
  * bitcoin-core/secp256k1#578: Avoid implementation-defined and undefined behavior when dealing with sizes
  * bitcoin-core/secp256k1#595: Allow to use external default callbacks
  * bitcoin-core/secp256k1#600: scratch space: use single allocation
  * bitcoin-core/secp256k1#592: Use trivial algorithm in ecmult_multi if scratch space is small
  * bitcoin-core/secp256k1#566: Enable context creation in preallocated memory
  * bitcoin-core/secp256k1#596: Make WINDOW_G configurable
  * bitcoin-core/secp256k1#561: Respect LDFLAGS and #undef STATIC_PRECOMPUTATION if using basic config
  * bitcoin-core/secp256k1#533: Make sure we're not using an uninitialized variable in secp256k1_wnaf_const(...)
  * bitcoin-core/secp256k1#617: Pass scalar by reference in secp256k1_wnaf_const()
  * bitcoin-core/secp256k1#619: Clear a copied secret key after negation
  * bitcoin-core/secp256k1#612: Allow field_10x26_arm.s to compile for ARMv7 architecture

ACKs for top commit:
  real-or-random:
    ACK e10439ce5a54cd13062e4ed07ebc681e385ed5cb I verified the diff (subtree matches my local tree, manual inspection of other commits) but I didn't tested the resulting code
  fanquake:
    ACK e10439ce5a54cd13062e4ed07ebc681e385ed5cb
  Sjors:
    ACK e10439ce5a54cd13062e4ed07ebc681e385ed5cb
  jonasnick:
    reACK e10439ce5a54cd13062e4ed07ebc681e385ed5cb

Tree-SHA512: eb6284a485da78e9d2ed3f771df85560d47c770ebf480a0d4121ab356ad26be101a2b973efe412f26e6c142bc1dbd2efbb5cc08774233e41918c59fe3dff3387
2021-08-11 00:05:22 +03:00

374 lines
14 KiB
C++

// Copyright (c) 2009-2015 The Bitcoin Core developers
// Copyright (c) 2017 The Zcash developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <key.h>
#include <arith_uint256.h>
#include <crypto/common.h>
#include <crypto/hmac_sha512.h>
#include <random.h>
#include <secp256k1.h>
#include <secp256k1_recovery.h>
static secp256k1_context* secp256k1_context_sign = nullptr;
/** These functions are taken from the libsecp256k1 distribution and are very ugly. */
/**
* This parses a format loosely based on a DER encoding of the ECPrivateKey type from
* section C.4 of SEC 1 <http://www.secg.org/sec1-v2.pdf>, with the following caveats:
*
* * The octet-length of the SEQUENCE must be encoded as 1 or 2 octets. It is not
* required to be encoded as one octet if it is less than 256, as DER would require.
* * The octet-length of the SEQUENCE must not be greater than the remaining
* length of the key encoding, but need not match it (i.e. the encoding may contain
* junk after the encoded SEQUENCE).
* * The privateKey OCTET STRING is zero-filled on the left to 32 octets.
* * Anything after the encoding of the privateKey OCTET STRING is ignored, whether
* or not it is validly encoded DER.
*
* out32 must point to an output buffer of length at least 32 bytes.
*/
static int ec_seckey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *seckey, size_t seckeylen) {
const unsigned char *end = seckey + seckeylen;
memset(out32, 0, 32);
/* sequence header */
if (end - seckey < 1 || *seckey != 0x30u) {
return 0;
}
seckey++;
/* sequence length constructor */
if (end - seckey < 1 || !(*seckey & 0x80u)) {
return 0;
}
ptrdiff_t lenb = *seckey & ~0x80u; seckey++;
if (lenb < 1 || lenb > 2) {
return 0;
}
if (end - seckey < lenb) {
return 0;
}
/* sequence length */
ptrdiff_t len = seckey[lenb-1] | (lenb > 1 ? seckey[lenb-2] << 8 : 0u);
seckey += lenb;
if (end - seckey < len) {
return 0;
}
/* sequence element 0: version number (=1) */
if (end - seckey < 3 || seckey[0] != 0x02u || seckey[1] != 0x01u || seckey[2] != 0x01u) {
return 0;
}
seckey += 3;
/* sequence element 1: octet string, up to 32 bytes */
if (end - seckey < 2 || seckey[0] != 0x04u) {
return 0;
}
ptrdiff_t oslen = seckey[1];
seckey += 2;
if (oslen > 32 || end - seckey < oslen) {
return 0;
}
memcpy(out32 + (32 - oslen), seckey, oslen);
if (!secp256k1_ec_seckey_verify(ctx, out32)) {
memset(out32, 0, 32);
return 0;
}
return 1;
}
/**
* This serializes to a DER encoding of the ECPrivateKey type from section C.4 of SEC 1
* <http://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
* included.
*
* seckey must point to an output buffer of length at least CKey::SIZE bytes.
* seckeylen must initially be set to the size of the seckey buffer. Upon return it
* will be set to the number of bytes used in the buffer.
* key32 must point to a 32-byte raw private key.
*/
static int ec_seckey_export_der(const secp256k1_context *ctx, unsigned char *seckey, size_t *seckeylen, const unsigned char *key32, bool compressed) {
assert(*seckeylen >= CKey::SIZE);
secp256k1_pubkey pubkey;
size_t pubkeylen = 0;
if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
*seckeylen = 0;
return 0;
}
if (compressed) {
static const unsigned char begin[] = {
0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
};
static const unsigned char middle[] = {
0xA0,0x81,0x85,0x30,0x81,0x82,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
0x21,0x02,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
0x17,0x98,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x24,0x03,0x22,0x00
};
unsigned char *ptr = seckey;
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
pubkeylen = CPubKey::COMPRESSED_SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_COMPRESSED);
ptr += pubkeylen;
*seckeylen = ptr - seckey;
assert(*seckeylen == CKey::COMPRESSED_SIZE);
} else {
static const unsigned char begin[] = {
0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
};
static const unsigned char middle[] = {
0xA0,0x81,0xA5,0x30,0x81,0xA2,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
0x41,0x04,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
0x17,0x98,0x48,0x3A,0xDA,0x77,0x26,0xA3,0xC4,0x65,0x5D,0xA4,0xFB,0xFC,0x0E,0x11,
0x08,0xA8,0xFD,0x17,0xB4,0x48,0xA6,0x85,0x54,0x19,0x9C,0x47,0xD0,0x8F,0xFB,0x10,
0xD4,0xB8,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x44,0x03,0x42,0x00
};
unsigned char *ptr = seckey;
memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
memcpy(ptr, key32, 32); ptr += 32;
memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
pubkeylen = CPubKey::SIZE;
secp256k1_ec_pubkey_serialize(ctx, ptr, &pubkeylen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
ptr += pubkeylen;
*seckeylen = ptr - seckey;
assert(*seckeylen == CKey::SIZE);
}
return 1;
}
bool CKey::Check(const unsigned char *vch) {
return secp256k1_ec_seckey_verify(secp256k1_context_sign, vch);
}
void CKey::MakeNewKey(bool fCompressedIn) {
do {
GetStrongRandBytes(keydata.data(), keydata.size());
} while (!Check(keydata.data()));
fValid = true;
fCompressed = fCompressedIn;
}
bool CKey::Negate()
{
assert(fValid);
return secp256k1_ec_seckey_negate(secp256k1_context_sign, keydata.data());
}
CPrivKey CKey::GetPrivKey() const {
assert(fValid);
CPrivKey seckey;
int ret;
size_t seckeylen;
seckey.resize(SIZE);
seckeylen = SIZE;
ret = ec_seckey_export_der(secp256k1_context_sign, seckey.data(), &seckeylen, begin(), fCompressed);
assert(ret);
seckey.resize(seckeylen);
return seckey;
}
CPubKey CKey::GetPubKey() const {
assert(fValid);
secp256k1_pubkey pubkey;
size_t clen = CPubKey::SIZE;
CPubKey result;
int ret = secp256k1_ec_pubkey_create(secp256k1_context_sign, &pubkey, begin());
assert(ret);
secp256k1_ec_pubkey_serialize(secp256k1_context_sign, (unsigned char*)result.begin(), &clen, &pubkey, fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
assert(result.size() == clen);
assert(result.IsValid());
return result;
}
// Check that the sig has a low R value and will be less than 71 bytes
bool SigHasLowR(const secp256k1_ecdsa_signature* sig)
{
unsigned char compact_sig[64];
secp256k1_ecdsa_signature_serialize_compact(secp256k1_context_sign, compact_sig, sig);
// In DER serialization, all values are interpreted as big-endian, signed integers. The highest bit in the integer indicates
// its signed-ness; 0 is positive, 1 is negative. When the value is interpreted as a negative integer, it must be converted
// to a positive value by prepending a 0x00 byte so that the highest bit is 0. We can avoid this prepending by ensuring that
// our highest bit is always 0, and thus we must check that the first byte is less than 0x80.
return compact_sig[0] < 0x80;
}
bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, bool grind, uint32_t test_case) const {
if (!fValid)
return false;
vchSig.resize(CPubKey::SIGNATURE_SIZE);
size_t nSigLen = CPubKey::SIGNATURE_SIZE;
unsigned char extra_entropy[32] = {0};
WriteLE32(extra_entropy, test_case);
secp256k1_ecdsa_signature sig;
uint32_t counter = 0;
int ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, (!grind && test_case) ? extra_entropy : nullptr);
// Grind for low R
while (ret && !SigHasLowR(&sig) && grind) {
WriteLE32(extra_entropy, ++counter);
ret = secp256k1_ecdsa_sign(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, extra_entropy);
}
assert(ret);
secp256k1_ecdsa_signature_serialize_der(secp256k1_context_sign, vchSig.data(), &nSigLen, &sig);
vchSig.resize(nSigLen);
return true;
}
bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
if (pubkey.IsCompressed() != fCompressed) {
return false;
}
unsigned char rnd[8];
std::string str = "Bitcoin key verification\n";
GetRandBytes(rnd, sizeof(rnd));
uint256 hash;
CHash256().Write(MakeUCharSpan(str)).Write(rnd).Finalize(hash);
std::vector<unsigned char> vchSig;
Sign(hash, vchSig);
return pubkey.Verify(hash, vchSig);
}
bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
if (!fValid)
return false;
vchSig.resize(CPubKey::COMPACT_SIGNATURE_SIZE);
int rec = -1;
secp256k1_ecdsa_recoverable_signature sig;
int ret = secp256k1_ecdsa_sign_recoverable(secp256k1_context_sign, &sig, hash.begin(), begin(), secp256k1_nonce_function_rfc6979, nullptr);
assert(ret);
ret = secp256k1_ecdsa_recoverable_signature_serialize_compact(secp256k1_context_sign, &vchSig[1], &rec, &sig);
assert(ret);
assert(rec != -1);
vchSig[0] = 27 + rec + (fCompressed ? 4 : 0);
return true;
}
bool CKey::Load(const CPrivKey &seckey, const CPubKey &vchPubKey, bool fSkipCheck=false) {
if (!ec_seckey_import_der(secp256k1_context_sign, (unsigned char*)begin(), seckey.data(), seckey.size()))
return false;
fCompressed = vchPubKey.IsCompressed();
fValid = true;
if (fSkipCheck)
return true;
return VerifyPubKey(vchPubKey);
}
bool CKey::Derive(CKey& keyChild, ChainCode &ccChild, unsigned int nChild, const ChainCode& cc) const {
assert(IsValid());
assert(IsCompressed());
std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
if ((nChild >> 31) == 0) {
CPubKey pubkey = GetPubKey();
assert(pubkey.size() == CPubKey::COMPRESSED_SIZE);
BIP32Hash(cc, nChild, *pubkey.begin(), pubkey.begin()+1, vout.data());
} else {
assert(size() == 32);
BIP32Hash(cc, nChild, 0, begin(), vout.data());
}
memcpy(ccChild.begin(), vout.data()+32, 32);
memcpy((unsigned char*)keyChild.begin(), begin(), 32);
bool ret = secp256k1_ec_seckey_tweak_add(secp256k1_context_sign, (unsigned char*)keyChild.begin(), vout.data());
keyChild.fCompressed = true;
keyChild.fValid = ret;
return ret;
}
bool CExtKey::Derive(CExtKey &out, unsigned int _nChild) const {
out.nDepth = nDepth + 1;
CKeyID id = key.GetPubKey().GetID();
memcpy(&out.vchFingerprint[0], &id, 4);
out.nChild = _nChild;
return key.Derive(out.key, out.chaincode, _nChild, chaincode);
}
void CExtKey::SetSeed(const unsigned char *seed, unsigned int nSeedLen) {
static const unsigned char hashkey[] = {'B','i','t','c','o','i','n',' ','s','e','e','d'};
std::vector<unsigned char, secure_allocator<unsigned char>> vout(64);
CHMAC_SHA512(hashkey, sizeof(hashkey)).Write(seed, nSeedLen).Finalize(vout.data());
key.Set(vout.data(), vout.data() + 32, true);
memcpy(chaincode.begin(), vout.data() + 32, 32);
nDepth = 0;
nChild = 0;
memset(vchFingerprint, 0, sizeof(vchFingerprint));
}
CExtPubKey CExtKey::Neuter() const {
CExtPubKey ret;
ret.nDepth = nDepth;
memcpy(&ret.vchFingerprint[0], &vchFingerprint[0], 4);
ret.nChild = nChild;
ret.pubkey = key.GetPubKey();
ret.chaincode = chaincode;
return ret;
}
void CExtKey::Encode(unsigned char code[BIP32_EXTKEY_SIZE]) const {
code[0] = nDepth;
memcpy(code+1, vchFingerprint, 4);
code[5] = (nChild >> 24) & 0xFF; code[6] = (nChild >> 16) & 0xFF;
code[7] = (nChild >> 8) & 0xFF; code[8] = (nChild >> 0) & 0xFF;
memcpy(code+9, chaincode.begin(), 32);
code[41] = 0;
assert(key.size() == 32);
memcpy(code+42, key.begin(), 32);
}
void CExtKey::Decode(const unsigned char code[BIP32_EXTKEY_SIZE]) {
nDepth = code[0];
memcpy(vchFingerprint, code+1, 4);
nChild = (code[5] << 24) | (code[6] << 16) | (code[7] << 8) | code[8];
memcpy(chaincode.begin(), code+9, 32);
key.Set(code+42, code+BIP32_EXTKEY_SIZE, true);
}
bool ECC_InitSanityCheck() {
CKey key;
key.MakeNewKey(true);
CPubKey pubkey = key.GetPubKey();
return key.VerifyPubKey(pubkey);
}
void ECC_Start() {
assert(secp256k1_context_sign == nullptr);
secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
assert(ctx != nullptr);
{
// Pass in a random blinding seed to the secp256k1 context.
std::vector<unsigned char, secure_allocator<unsigned char>> vseed(32);
GetRandBytes(vseed.data(), 32);
bool ret = secp256k1_context_randomize(ctx, vseed.data());
assert(ret);
}
secp256k1_context_sign = ctx;
}
void ECC_Stop() {
secp256k1_context *ctx = secp256k1_context_sign;
secp256k1_context_sign = nullptr;
if (ctx) {
secp256k1_context_destroy(ctx);
}
}