diff options
Diffstat (limited to 'src/key.cpp')
| -rw-r--r-- | src/key.cpp | 263 |
1 files changed, 262 insertions, 1 deletions
diff --git a/src/key.cpp b/src/key.cpp index e0844412d9..ece835d147 100644 --- a/src/key.cpp +++ b/src/key.cpp @@ -2,8 +2,10 @@ // Distributed under the MIT/X11 software license, see the accompanying // file license.txt or http://www.opensource.org/licenses/mit-license.php. -#include <openssl/ec.h> #include <openssl/ecdsa.h> +#include <openssl/obj_mac.h> + +#include "key.h" // Generate a private key from just the secret parameter int EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key) @@ -115,3 +117,262 @@ err: if (Q != NULL) EC_POINT_free(Q); return ret; } + +void CKey::SetCompressedPubKey() +{ + EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED); + fCompressedPubKey = true; +} + +void CKey::Reset() +{ + fCompressedPubKey = false; + pkey = EC_KEY_new_by_curve_name(NID_secp256k1); + if (pkey == NULL) + throw key_error("CKey::CKey() : EC_KEY_new_by_curve_name failed"); + fSet = false; +} + +CKey::CKey() +{ + Reset(); +} + +CKey::CKey(const CKey& b) +{ + pkey = EC_KEY_dup(b.pkey); + if (pkey == NULL) + throw key_error("CKey::CKey(const CKey&) : EC_KEY_dup failed"); + fSet = b.fSet; +} + +CKey& CKey::operator=(const CKey& b) +{ + if (!EC_KEY_copy(pkey, b.pkey)) + throw key_error("CKey::operator=(const CKey&) : EC_KEY_copy failed"); + fSet = b.fSet; + return (*this); +} + +CKey::~CKey() +{ + EC_KEY_free(pkey); +} + +bool CKey::IsNull() const +{ + return !fSet; +} + +bool CKey::IsCompressed() const +{ + return fCompressedPubKey; +} + +void CKey::MakeNewKey(bool fCompressed) +{ + if (!EC_KEY_generate_key(pkey)) + throw key_error("CKey::MakeNewKey() : EC_KEY_generate_key failed"); + if (fCompressed) + SetCompressedPubKey(); + fSet = true; +} + +bool CKey::SetPrivKey(const CPrivKey& vchPrivKey) +{ + const unsigned char* pbegin = &vchPrivKey[0]; + if (!d2i_ECPrivateKey(&pkey, &pbegin, vchPrivKey.size())) + return false; + fSet = true; + return true; +} + +bool CKey::SetSecret(const CSecret& vchSecret, bool fCompressed) +{ + EC_KEY_free(pkey); + pkey = EC_KEY_new_by_curve_name(NID_secp256k1); + if (pkey == NULL) + throw key_error("CKey::SetSecret() : EC_KEY_new_by_curve_name failed"); + if (vchSecret.size() != 32) + throw key_error("CKey::SetSecret() : secret must be 32 bytes"); + BIGNUM *bn = BN_bin2bn(&vchSecret[0],32,BN_new()); + if (bn == NULL) + throw key_error("CKey::SetSecret() : BN_bin2bn failed"); + if (!EC_KEY_regenerate_key(pkey,bn)) + { + BN_clear_free(bn); + throw key_error("CKey::SetSecret() : EC_KEY_regenerate_key failed"); + } + BN_clear_free(bn); + fSet = true; + if (fCompressed || fCompressedPubKey) + SetCompressedPubKey(); + return true; +} + +CSecret CKey::GetSecret(bool &fCompressed) const +{ + CSecret vchRet; + vchRet.resize(32); + const BIGNUM *bn = EC_KEY_get0_private_key(pkey); + int nBytes = BN_num_bytes(bn); + if (bn == NULL) + throw key_error("CKey::GetSecret() : EC_KEY_get0_private_key failed"); + int n=BN_bn2bin(bn,&vchRet[32 - nBytes]); + if (n != nBytes) + throw key_error("CKey::GetSecret(): BN_bn2bin failed"); + fCompressed = fCompressedPubKey; + return vchRet; +} + +CPrivKey CKey::GetPrivKey() const +{ + int nSize = i2d_ECPrivateKey(pkey, NULL); + if (!nSize) + throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey failed"); + CPrivKey vchPrivKey(nSize, 0); + unsigned char* pbegin = &vchPrivKey[0]; + if (i2d_ECPrivateKey(pkey, &pbegin) != nSize) + throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey returned unexpected size"); + return vchPrivKey; +} + +bool CKey::SetPubKey(const std::vector<unsigned char>& vchPubKey) +{ + const unsigned char* pbegin = &vchPubKey[0]; + if (!o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.size())) + return false; + fSet = true; + if (vchPubKey.size() == 33) + SetCompressedPubKey(); + return true; +} + +std::vector<unsigned char> CKey::GetPubKey() const +{ + int nSize = i2o_ECPublicKey(pkey, NULL); + if (!nSize) + throw key_error("CKey::GetPubKey() : i2o_ECPublicKey failed"); + std::vector<unsigned char> vchPubKey(nSize, 0); + unsigned char* pbegin = &vchPubKey[0]; + if (i2o_ECPublicKey(pkey, &pbegin) != nSize) + throw key_error("CKey::GetPubKey() : i2o_ECPublicKey returned unexpected size"); + return vchPubKey; +} + +bool CKey::Sign(uint256 hash, std::vector<unsigned char>& vchSig) +{ + unsigned int nSize = ECDSA_size(pkey); + vchSig.resize(nSize); // Make sure it is big enough + if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], &nSize, pkey)) + { + vchSig.clear(); + return false; + } + vchSig.resize(nSize); // Shrink to fit actual size + return true; +} + +// create a compact signature (65 bytes), which allows reconstructing the used public key +// The format is one header byte, followed by two times 32 bytes for the serialized r and s values. +// The header byte: 0x1B = first key with even y, 0x1C = first key with odd y, +// 0x1D = second key with even y, 0x1E = second key with odd y +bool CKey::SignCompact(uint256 hash, std::vector<unsigned char>& vchSig) +{ + bool fOk = false; + ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey); + if (sig==NULL) + return false; + vchSig.clear(); + vchSig.resize(65,0); + int nBitsR = BN_num_bits(sig->r); + int nBitsS = BN_num_bits(sig->s); + if (nBitsR <= 256 && nBitsS <= 256) + { + int nRecId = -1; + for (int i=0; i<4; i++) + { + CKey keyRec; + keyRec.fSet = true; + if (fCompressedPubKey) + keyRec.SetCompressedPubKey(); + if (ECDSA_SIG_recover_key_GFp(keyRec.pkey, sig, (unsigned char*)&hash, sizeof(hash), i, 1) == 1) + if (keyRec.GetPubKey() == this->GetPubKey()) + { + nRecId = i; + break; + } + } + + if (nRecId == -1) + throw key_error("CKey::SignCompact() : unable to construct recoverable key"); + + vchSig[0] = nRecId+27+(fCompressedPubKey ? 4 : 0); + BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]); + BN_bn2bin(sig->s,&vchSig[65-(nBitsS+7)/8]); + fOk = true; + } + ECDSA_SIG_free(sig); + return fOk; +} + +// reconstruct public key from a compact signature +// This is only slightly more CPU intensive than just verifying it. +// If this function succeeds, the recovered public key is guaranteed to be valid +// (the signature is a valid signature of the given data for that key) +bool CKey::SetCompactSignature(uint256 hash, const std::vector<unsigned char>& vchSig) +{ + if (vchSig.size() != 65) + return false; + int nV = vchSig[0]; + if (nV<27 || nV>=35) + return false; + ECDSA_SIG *sig = ECDSA_SIG_new(); + BN_bin2bn(&vchSig[1],32,sig->r); + BN_bin2bn(&vchSig[33],32,sig->s); + + EC_KEY_free(pkey); + pkey = EC_KEY_new_by_curve_name(NID_secp256k1); + if (nV >= 31) + { + SetCompressedPubKey(); + nV -= 4; + } + if (ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), nV - 27, 0) == 1) + { + fSet = true; + ECDSA_SIG_free(sig); + return true; + } + return false; +} + +bool CKey::Verify(uint256 hash, const std::vector<unsigned char>& vchSig) +{ + // -1 = error, 0 = bad sig, 1 = good + if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1) + return false; + return true; +} + +bool CKey::VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig) +{ + CKey key; + if (!key.SetCompactSignature(hash, vchSig)) + return false; + if (GetPubKey() != key.GetPubKey()) + return false; + return true; +} + +bool CKey::IsValid() +{ + if (!fSet) + return false; + + bool fCompr; + CSecret secret = GetSecret(fCompr); + CKey key2; + key2.SetSecret(secret, fCompr); + return GetPubKey() == key2.GetPubKey(); +} |