// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-#include <openssl/ec.h>
+#include <map>
+
#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)
// Perform ECDSA key recovery (see SEC1 4.1.6) for curves over (mod p)-fields
// recid selects which key is recovered
-// if check is nonzero, additional checks are performed
+// if check is non-zero, additional checks are performed
int ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check)
{
if (!eckey) return 0;
if (Q != NULL) EC_POINT_free(Q);
return ret;
}
+
+int CompareBigEndian(const unsigned char *c1, size_t c1len, const unsigned char *c2, size_t c2len) {
+ while (c1len > c2len) {
+ if (*c1)
+ return 1;
+ c1++;
+ c1len--;
+ }
+ while (c2len > c1len) {
+ if (*c2)
+ return -1;
+ c2++;
+ c2len--;
+ }
+ while (c1len > 0) {
+ if (*c1 > *c2)
+ return 1;
+ if (*c2 > *c1)
+ return -1;
+ c1++;
+ c2++;
+ c1len--;
+ }
+ return 0;
+}
+
+// Order of secp256k1's generator minus 1.
+const unsigned char vchMaxModOrder[32] = {
+ 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,0xD0,0x36,0x41,0x40
+};
+
+// Half of the order of secp256k1's generator minus 1.
+const unsigned char vchMaxModHalfOrder[32] = {
+ 0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+ 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+ 0x5D,0x57,0x6E,0x73,0x57,0xA4,0x50,0x1D,
+ 0xDF,0xE9,0x2F,0x46,0x68,0x1B,0x20,0xA0
+};
+
+const unsigned char vchZero[0] = {};
+
+
+
+void CKey::SetCompressedPubKey()
+{
+ EC_KEY_set_conv_form(pkey, POINT_CONVERSION_COMPRESSED);
+ fCompressedPubKey = true;
+}
+
+void CKey::Reset()
+{
+ fCompressedPubKey = false;
+ if (pkey != NULL)
+ EC_KEY_free(pkey);
+ 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()
+{
+ pkey = NULL;
+ 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;
+}
+
+bool CKey::CheckSignatureElement(const unsigned char *vch, int len, bool half) {
+ return CompareBigEndian(vch, len, vchZero, 0) > 0 &&
+ CompareBigEndian(vch, len, half ? vchMaxModHalfOrder : vchMaxModOrder, 32) <= 0;
+}
+
+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()))
+ {
+ // In testing, d2i_ECPrivateKey can return true
+ // but fill in pkey with a key that fails
+ // EC_KEY_check_key, so:
+ if (EC_KEY_check_key(pkey))
+ {
+ fSet = true;
+ return true;
+ }
+ }
+ // If vchPrivKey data is bad d2i_ECPrivateKey() can
+ // leave pkey in a state where calling EC_KEY_free()
+ // crashes. To avoid that, set pkey to NULL and
+ // leak the memory (a leak is better than a crash)
+ pkey = NULL;
+ Reset();
+ return false;
+}
+
+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 CPubKey& vchPubKey)
+{
+ const unsigned char* pbegin = &vchPubKey.vchPubKey[0];
+ if (o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.vchPubKey.size()))
+ {
+ fSet = true;
+ if (vchPubKey.vchPubKey.size() == 33)
+ SetCompressedPubKey();
+ return true;
+ }
+ pkey = NULL;
+ Reset();
+ return false;
+}
+
+CPubKey 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 CPubKey(vchPubKey);
+}
+
+bool CKey::Sign(uint256 hash, std::vector<unsigned char>& vchSig)
+{
+ vchSig.clear();
+ ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
+ if (sig==NULL)
+ return false;
+ const EC_GROUP *group = EC_KEY_get0_group(pkey);
+ CBigNum order, halforder;
+ EC_GROUP_get_order(group, &order, NULL);
+ BN_rshift1(&halforder, &order);
+ // enforce low S values, by negating the value (modulo the order) if above order/2.
+ if (BN_cmp(sig->s, &halforder) > 0) {
+ BN_sub(sig->s, &order, sig->s);
+ }
+ unsigned int nSize = ECDSA_size(pkey);
+ vchSig.resize(nSize); // Make sure it is big enough
+ unsigned char *pos = &vchSig[0];
+ nSize = i2d_ECDSA_SIG(sig, &pos);
+ ECDSA_SIG_free(sig);
+ vchSig.resize(nSize); // Shrink to fit actual size
+ // Testing our new signature
+ if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1) {
+ vchSig.clear();
+ return false;
+ }
+ 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;
+ const EC_GROUP *group = EC_KEY_get0_group(pkey);
+ CBigNum order, halforder;
+ EC_GROUP_get_order(group, &order, NULL);
+ BN_rshift1(&halforder, &order);
+ // enforce low S values, by negating the value (modulo the order) if above order/2.
+ if (BN_cmp(sig->s, &halforder) > 0) {
+ BN_sub(sig->s, &order, sig->s);
+ }
+ 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)
+ {
+ ECDSA_SIG_free(sig);
+ 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;
+ }
+ ECDSA_SIG_free(sig);
+ 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;
+
+ if (!EC_KEY_check_key(pkey))
+ return false;
+
+ bool fCompr;
+ CSecret secret = GetSecret(fCompr);
+ CKey key2;
+ key2.SetSecret(secret, fCompr);
+ return GetPubKey() == key2.GetPubKey();
+}