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328 lines
10 KiB
328 lines
10 KiB
// Copyright (c) 2009-2010 Satoshi Nakamoto |
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// Copyright (c) 2009-2012 The Bitcoin developers |
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// Distributed under the MIT/X11 software license, see the accompanying |
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// file license.txt or http://www.opensource.org/licenses/mit-license.php. |
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#ifndef BITCOIN_KEY_H |
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#define BITCOIN_KEY_H |
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#include <stdexcept> |
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#include <vector> |
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#include <openssl/ec.h> |
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#include <openssl/ecdsa.h> |
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#include <openssl/obj_mac.h> |
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#include "allocators.h" |
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#include "uint256.h" |
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// secp160k1 |
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// const unsigned int PRIVATE_KEY_SIZE = 192; |
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// const unsigned int PUBLIC_KEY_SIZE = 41; |
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// const unsigned int SIGNATURE_SIZE = 48; |
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// |
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// secp192k1 |
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// const unsigned int PRIVATE_KEY_SIZE = 222; |
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// const unsigned int PUBLIC_KEY_SIZE = 49; |
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// const unsigned int SIGNATURE_SIZE = 57; |
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// |
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// secp224k1 |
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// const unsigned int PRIVATE_KEY_SIZE = 250; |
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// const unsigned int PUBLIC_KEY_SIZE = 57; |
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// const unsigned int SIGNATURE_SIZE = 66; |
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// |
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// secp256k1: |
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// const unsigned int PRIVATE_KEY_SIZE = 279; |
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// const unsigned int PUBLIC_KEY_SIZE = 65; |
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// const unsigned int SIGNATURE_SIZE = 72; |
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// |
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// see www.keylength.com |
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// script supports up to 75 for single byte push |
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int extern EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key); |
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int extern 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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class key_error : public std::runtime_error |
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{ |
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public: |
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explicit key_error(const std::string& str) : std::runtime_error(str) {} |
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}; |
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// secure_allocator is defined in serialize.h |
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// CPrivKey is a serialized private key, with all parameters included (279 bytes) |
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typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey; |
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// CSecret is a serialization of just the secret parameter (32 bytes) |
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typedef std::vector<unsigned char, secure_allocator<unsigned char> > CSecret; |
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/** An encapsulated OpenSSL Elliptic Curve key (public and/or private) */ |
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class CKey |
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{ |
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protected: |
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EC_KEY* pkey; |
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bool fSet; |
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bool fCompressedPubKey; |
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void SetCompressedPubKey() |
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{ |
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EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED); |
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fCompressedPubKey = true; |
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} |
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public: |
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void Reset() |
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{ |
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fCompressedPubKey = false; |
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pkey = EC_KEY_new_by_curve_name(NID_secp256k1); |
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if (pkey == NULL) |
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throw key_error("CKey::CKey() : EC_KEY_new_by_curve_name failed"); |
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fSet = false; |
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} |
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CKey() |
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{ |
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Reset(); |
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} |
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CKey(const CKey& b) |
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{ |
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pkey = EC_KEY_dup(b.pkey); |
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if (pkey == NULL) |
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throw key_error("CKey::CKey(const CKey&) : EC_KEY_dup failed"); |
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fSet = b.fSet; |
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} |
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CKey& operator=(const CKey& b) |
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{ |
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if (!EC_KEY_copy(pkey, b.pkey)) |
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throw key_error("CKey::operator=(const CKey&) : EC_KEY_copy failed"); |
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fSet = b.fSet; |
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return (*this); |
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} |
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~CKey() |
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{ |
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EC_KEY_free(pkey); |
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} |
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bool IsNull() const |
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{ |
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return !fSet; |
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} |
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bool IsCompressed() const |
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{ |
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return fCompressedPubKey; |
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} |
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void MakeNewKey(bool fCompressed) |
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{ |
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if (!EC_KEY_generate_key(pkey)) |
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throw key_error("CKey::MakeNewKey() : EC_KEY_generate_key failed"); |
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if (fCompressed) |
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SetCompressedPubKey(); |
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fSet = true; |
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} |
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bool SetPrivKey(const CPrivKey& vchPrivKey) |
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{ |
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const unsigned char* pbegin = &vchPrivKey[0]; |
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if (!d2i_ECPrivateKey(&pkey, &pbegin, vchPrivKey.size())) |
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return false; |
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fSet = true; |
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return true; |
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} |
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bool SetSecret(const CSecret& vchSecret, bool fCompressed = false) |
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{ |
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EC_KEY_free(pkey); |
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pkey = EC_KEY_new_by_curve_name(NID_secp256k1); |
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if (pkey == NULL) |
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throw key_error("CKey::SetSecret() : EC_KEY_new_by_curve_name failed"); |
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if (vchSecret.size() != 32) |
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throw key_error("CKey::SetSecret() : secret must be 32 bytes"); |
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BIGNUM *bn = BN_bin2bn(&vchSecret[0],32,BN_new()); |
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if (bn == NULL) |
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throw key_error("CKey::SetSecret() : BN_bin2bn failed"); |
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if (!EC_KEY_regenerate_key(pkey,bn)) |
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{ |
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BN_clear_free(bn); |
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throw key_error("CKey::SetSecret() : EC_KEY_regenerate_key failed"); |
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} |
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BN_clear_free(bn); |
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fSet = true; |
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if (fCompressed || fCompressedPubKey) |
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SetCompressedPubKey(); |
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return true; |
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} |
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CSecret GetSecret(bool &fCompressed) const |
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{ |
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CSecret vchRet; |
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vchRet.resize(32); |
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const BIGNUM *bn = EC_KEY_get0_private_key(pkey); |
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int nBytes = BN_num_bytes(bn); |
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if (bn == NULL) |
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throw key_error("CKey::GetSecret() : EC_KEY_get0_private_key failed"); |
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int n=BN_bn2bin(bn,&vchRet[32 - nBytes]); |
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if (n != nBytes) |
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throw key_error("CKey::GetSecret(): BN_bn2bin failed"); |
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fCompressed = fCompressedPubKey; |
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return vchRet; |
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} |
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CPrivKey GetPrivKey() const |
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{ |
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int nSize = i2d_ECPrivateKey(pkey, NULL); |
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if (!nSize) |
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throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey failed"); |
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CPrivKey vchPrivKey(nSize, 0); |
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unsigned char* pbegin = &vchPrivKey[0]; |
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if (i2d_ECPrivateKey(pkey, &pbegin) != nSize) |
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throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey returned unexpected size"); |
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return vchPrivKey; |
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} |
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bool SetPubKey(const std::vector<unsigned char>& vchPubKey) |
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{ |
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const unsigned char* pbegin = &vchPubKey[0]; |
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if (!o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.size())) |
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return false; |
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fSet = true; |
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if (vchPubKey.size() == 33) |
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SetCompressedPubKey(); |
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return true; |
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} |
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std::vector<unsigned char> GetPubKey() const |
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{ |
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int nSize = i2o_ECPublicKey(pkey, NULL); |
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if (!nSize) |
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throw key_error("CKey::GetPubKey() : i2o_ECPublicKey failed"); |
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std::vector<unsigned char> vchPubKey(nSize, 0); |
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unsigned char* pbegin = &vchPubKey[0]; |
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if (i2o_ECPublicKey(pkey, &pbegin) != nSize) |
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throw key_error("CKey::GetPubKey() : i2o_ECPublicKey returned unexpected size"); |
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return vchPubKey; |
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} |
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bool Sign(uint256 hash, std::vector<unsigned char>& vchSig) |
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{ |
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unsigned int nSize = ECDSA_size(pkey); |
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vchSig.resize(nSize); // Make sure it is big enough |
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if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], &nSize, pkey)) |
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{ |
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vchSig.clear(); |
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return false; |
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} |
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vchSig.resize(nSize); // Shrink to fit actual size |
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return true; |
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} |
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// create a compact signature (65 bytes), which allows reconstructing the used public key |
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// The format is one header byte, followed by two times 32 bytes for the serialized r and s values. |
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// The header byte: 0x1B = first key with even y, 0x1C = first key with odd y, |
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// 0x1D = second key with even y, 0x1E = second key with odd y |
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bool SignCompact(uint256 hash, std::vector<unsigned char>& vchSig) |
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{ |
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bool fOk = false; |
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ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey); |
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if (sig==NULL) |
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return false; |
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vchSig.clear(); |
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vchSig.resize(65,0); |
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int nBitsR = BN_num_bits(sig->r); |
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int nBitsS = BN_num_bits(sig->s); |
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if (nBitsR <= 256 && nBitsS <= 256) |
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{ |
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int nRecId = -1; |
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for (int i=0; i<4; i++) |
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{ |
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CKey keyRec; |
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keyRec.fSet = true; |
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if (fCompressedPubKey) |
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keyRec.SetCompressedPubKey(); |
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if (ECDSA_SIG_recover_key_GFp(keyRec.pkey, sig, (unsigned char*)&hash, sizeof(hash), i, 1) == 1) |
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if (keyRec.GetPubKey() == this->GetPubKey()) |
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{ |
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nRecId = i; |
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break; |
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} |
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} |
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if (nRecId == -1) |
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throw key_error("CKey::SignCompact() : unable to construct recoverable key"); |
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vchSig[0] = nRecId+27+(fCompressedPubKey ? 4 : 0); |
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BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]); |
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BN_bn2bin(sig->s,&vchSig[65-(nBitsS+7)/8]); |
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fOk = true; |
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} |
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ECDSA_SIG_free(sig); |
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return fOk; |
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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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bool SetCompactSignature(uint256 hash, const std::vector<unsigned char>& vchSig) |
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{ |
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if (vchSig.size() != 65) |
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return false; |
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int nV = vchSig[0]; |
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if (nV<27 || nV>=35) |
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return false; |
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ECDSA_SIG *sig = ECDSA_SIG_new(); |
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BN_bin2bn(&vchSig[1],32,sig->r); |
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BN_bin2bn(&vchSig[33],32,sig->s); |
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EC_KEY_free(pkey); |
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pkey = EC_KEY_new_by_curve_name(NID_secp256k1); |
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if (nV >= 31) |
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{ |
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SetCompressedPubKey(); |
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nV -= 4; |
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} |
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if (ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), nV - 27, 0) == 1) |
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{ |
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fSet = true; |
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ECDSA_SIG_free(sig); |
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return true; |
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} |
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return false; |
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} |
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bool Verify(uint256 hash, const std::vector<unsigned char>& vchSig) |
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{ |
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// -1 = error, 0 = bad sig, 1 = good |
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if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1) |
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return false; |
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return true; |
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} |
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// Verify a compact signature |
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bool VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig) |
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{ |
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CKey key; |
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if (!key.SetCompactSignature(hash, vchSig)) |
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return false; |
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if (GetPubKey() != key.GetPubKey()) |
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return false; |
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return true; |
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} |
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bool IsValid() |
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{ |
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if (!fSet) |
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return false; |
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bool fCompr; |
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CSecret secret = GetSecret(fCompr); |
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CKey key2; |
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key2.SetSecret(secret, fCompr); |
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return GetPubKey() == key2.GetPubKey(); |
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} |
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}; |
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#endif
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