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@ -4,19 +4,184 @@
@@ -4,19 +4,184 @@
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#include "pubkey.h" |
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#include "eccryptoverify.h" |
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#include <secp256k1.h> |
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#include <secp256k1_recovery.h> |
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#include "ecwrapper.h" |
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namespace |
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{ |
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/* Global secp256k1_context object used for verification. */ |
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secp256k1_context* secp256k1_context_verify = NULL; |
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} |
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/** This function is taken from the libsecp256k1 distribution and implements
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* DER parsing for ECDSA signatures, while supporting an arbitrary subset of |
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* format violations. |
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* |
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* Supported violations include negative integers, excessive padding, garbage |
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* at the end, and overly long length descriptors. This is safe to use in |
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* Bitcoin because since the activation of BIP66, signatures are verified to be |
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* strict DER before being passed to this module, and we know it supports all |
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* violations present in the blockchain before that point. |
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*/ |
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static int ecdsa_signature_parse_der_lax(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input, size_t inputlen) { |
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size_t rpos, rlen, spos, slen; |
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size_t pos = 0; |
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size_t lenbyte; |
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unsigned char tmpsig[64] = {0}; |
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int overflow = 0; |
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/* Hack to initialize sig with a correctly-parsed but invalid signature. */ |
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secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig); |
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/* Sequence tag byte */ |
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if (pos == inputlen || input[pos] != 0x30) { |
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return 0; |
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} |
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pos++; |
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/* Sequence length bytes */ |
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if (pos == inputlen) { |
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return 0; |
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} |
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lenbyte = input[pos++]; |
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if (lenbyte & 0x80) { |
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lenbyte -= 0x80; |
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if (pos + lenbyte > inputlen) { |
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return 0; |
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} |
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pos += lenbyte; |
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} |
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/* Integer tag byte for R */ |
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if (pos == inputlen || input[pos] != 0x02) { |
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return 0; |
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} |
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pos++; |
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/* Integer length for R */ |
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if (pos == inputlen) { |
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return 0; |
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} |
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lenbyte = input[pos++]; |
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if (lenbyte & 0x80) { |
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lenbyte -= 0x80; |
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if (pos + lenbyte > inputlen) { |
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return 0; |
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} |
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while (lenbyte > 0 && input[pos] == 0) { |
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pos++; |
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lenbyte--; |
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} |
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if (lenbyte >= sizeof(size_t)) { |
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return 0; |
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} |
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rlen = 0; |
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while (lenbyte > 0) { |
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rlen = (rlen << 8) + input[pos]; |
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pos++; |
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lenbyte--; |
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} |
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} else { |
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rlen = lenbyte; |
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} |
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if (rlen > inputlen - pos) { |
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return 0; |
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} |
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rpos = pos; |
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pos += rlen; |
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/* Integer tag byte for S */ |
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if (pos == inputlen || input[pos] != 0x02) { |
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return 0; |
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} |
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pos++; |
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/* Integer length for S */ |
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if (pos == inputlen) { |
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return 0; |
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} |
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lenbyte = input[pos++]; |
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if (lenbyte & 0x80) { |
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lenbyte -= 0x80; |
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if (pos + lenbyte > inputlen) { |
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return 0; |
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} |
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while (lenbyte > 0 && input[pos] == 0) { |
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pos++; |
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lenbyte--; |
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} |
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if (lenbyte >= sizeof(size_t)) { |
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return 0; |
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} |
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slen = 0; |
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while (lenbyte > 0) { |
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slen = (slen << 8) + input[pos]; |
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pos++; |
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lenbyte--; |
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} |
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} else { |
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slen = lenbyte; |
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} |
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if (slen > inputlen - pos) { |
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return 0; |
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} |
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spos = pos; |
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pos += slen; |
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/* Ignore leading zeroes in R */ |
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while (rlen > 0 && input[rpos] == 0) { |
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rlen--; |
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rpos++; |
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} |
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/* Copy R value */ |
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if (rlen > 32) { |
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overflow = 1; |
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} else { |
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memcpy(tmpsig + 32 - rlen, input + rpos, rlen); |
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} |
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/* Ignore leading zeroes in S */ |
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while (slen > 0 && input[spos] == 0) { |
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slen--; |
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spos++; |
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} |
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/* Copy S value */ |
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if (slen > 32) { |
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overflow = 1; |
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} else { |
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memcpy(tmpsig + 64 - slen, input + spos, slen); |
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} |
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if (!overflow) { |
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overflow = !secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig); |
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} |
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if (overflow) { |
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/* Overwrite the result again with a correctly-parsed but invalid
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signature if parsing failed. */ |
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memset(tmpsig, 0, 64); |
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secp256k1_ecdsa_signature_parse_compact(ctx, sig, tmpsig); |
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} |
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return 1; |
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} |
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bool CPubKey::Verify(const uint256 &hash, const std::vector<unsigned char>& vchSig) const { |
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if (!IsValid()) |
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return false; |
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CECKey key; |
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if (!key.SetPubKey(begin(), size())) |
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secp256k1_pubkey pubkey; |
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secp256k1_ecdsa_signature sig; |
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if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, &(*this)[0], size())) { |
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return false; |
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if (!key.Verify(hash, vchSig)) |
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} |
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if (vchSig.size() == 0) { |
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return false; |
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return true; |
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} |
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if (!ecdsa_signature_parse_der_lax(secp256k1_context_verify, &sig, &vchSig[0], vchSig.size())) { |
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return false; |
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} |
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/* libsecp256k1's ECDSA verification requires lower-S signatures, which have
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* not historically been enforced in Bitcoin, so normalize them first. */ |
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secp256k1_ecdsa_signature_normalize(secp256k1_context_verify, &sig, &sig); |
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return secp256k1_ecdsa_verify(secp256k1_context_verify, &sig, hash.begin(), &pubkey); |
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} |
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bool CPubKey::RecoverCompact(const uint256 &hash, const std::vector<unsigned char>& vchSig) { |
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@ -24,33 +189,39 @@ bool CPubKey::RecoverCompact(const uint256 &hash, const std::vector<unsigned cha
@@ -24,33 +189,39 @@ bool CPubKey::RecoverCompact(const uint256 &hash, const std::vector<unsigned cha
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return false; |
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int recid = (vchSig[0] - 27) & 3; |
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bool fComp = ((vchSig[0] - 27) & 4) != 0; |
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CECKey key; |
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if (!key.Recover(hash, &vchSig[1], recid)) |
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secp256k1_pubkey pubkey; |
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secp256k1_ecdsa_recoverable_signature sig; |
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if (!secp256k1_ecdsa_recoverable_signature_parse_compact(secp256k1_context_verify, &sig, &vchSig[1], recid)) { |
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return false; |
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} |
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if (!secp256k1_ecdsa_recover(secp256k1_context_verify, &pubkey, &sig, hash.begin())) { |
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return false; |
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std::vector<unsigned char> pubkey; |
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key.GetPubKey(pubkey, fComp); |
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Set(pubkey.begin(), pubkey.end()); |
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} |
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unsigned char pub[65]; |
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size_t publen = 65; |
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secp256k1_ec_pubkey_serialize(secp256k1_context_verify, pub, &publen, &pubkey, fComp ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED); |
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Set(pub, pub + publen); |
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return true; |
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} |
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bool CPubKey::IsFullyValid() const { |
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if (!IsValid()) |
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return false; |
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CECKey key; |
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if (!key.SetPubKey(begin(), size())) |
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return false; |
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return true; |
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secp256k1_pubkey pubkey; |
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return secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, &(*this)[0], size()); |
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} |
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bool CPubKey::Decompress() { |
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if (!IsValid()) |
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return false; |
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CECKey key; |
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if (!key.SetPubKey(begin(), size())) |
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secp256k1_pubkey pubkey; |
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if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, &(*this)[0], size())) { |
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return false; |
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std::vector<unsigned char> pubkey; |
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key.GetPubKey(pubkey, false); |
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Set(pubkey.begin(), pubkey.end()); |
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} |
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unsigned char pub[65]; |
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size_t publen = 65; |
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secp256k1_ec_pubkey_serialize(secp256k1_context_verify, pub, &publen, &pubkey, SECP256K1_EC_UNCOMPRESSED); |
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Set(pub, pub + publen); |
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return true; |
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} |
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@ -61,13 +232,18 @@ bool CPubKey::Derive(CPubKey& pubkeyChild, ChainCode &ccChild, unsigned int nChi
@@ -61,13 +232,18 @@ bool CPubKey::Derive(CPubKey& pubkeyChild, ChainCode &ccChild, unsigned int nChi
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unsigned char out[64]; |
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BIP32Hash(cc, nChild, *begin(), begin()+1, out); |
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memcpy(ccChild.begin(), out+32, 32); |
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CECKey key; |
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bool ret = key.SetPubKey(begin(), size()); |
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ret &= key.TweakPublic(out); |
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std::vector<unsigned char> pubkey; |
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key.GetPubKey(pubkey, true); |
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pubkeyChild.Set(pubkey.begin(), pubkey.end()); |
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return ret; |
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secp256k1_pubkey pubkey; |
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if (!secp256k1_ec_pubkey_parse(secp256k1_context_verify, &pubkey, &(*this)[0], size())) { |
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return false; |
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} |
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if (!secp256k1_ec_pubkey_tweak_add(secp256k1_context_verify, &pubkey, out)) { |
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return false; |
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} |
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unsigned char pub[33]; |
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size_t publen = 33; |
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secp256k1_ec_pubkey_serialize(secp256k1_context_verify, pub, &publen, &pubkey, SECP256K1_EC_COMPRESSED); |
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pubkeyChild.Set(pub, pub + publen); |
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return true; |
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} |
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void CExtPubKey::Encode(unsigned char code[74]) const { |
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@ -95,3 +271,33 @@ bool CExtPubKey::Derive(CExtPubKey &out, unsigned int nChild) const {
@@ -95,3 +271,33 @@ bool CExtPubKey::Derive(CExtPubKey &out, unsigned int nChild) const {
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out.nChild = nChild; |
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return pubkey.Derive(out.pubkey, out.chaincode, nChild, chaincode); |
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} |
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/* static */ bool CPubKey::CheckLowS(const std::vector<unsigned char>& vchSig) { |
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secp256k1_ecdsa_signature sig; |
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if (!ecdsa_signature_parse_der_lax(secp256k1_context_verify, &sig, &vchSig[0], vchSig.size())) { |
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return false; |
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} |
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return (!secp256k1_ecdsa_signature_normalize(secp256k1_context_verify, NULL, &sig)); |
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} |
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/* static */ int ECCVerifyHandle::refcount = 0; |
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ECCVerifyHandle::ECCVerifyHandle() |
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{ |
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if (refcount == 0) { |
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assert(secp256k1_context_verify == NULL); |
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secp256k1_context_verify = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY); |
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assert(secp256k1_context_verify != NULL); |
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} |
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refcount++; |
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} |
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ECCVerifyHandle::~ECCVerifyHandle() |
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{ |
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refcount--; |
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if (refcount == 0) { |
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assert(secp256k1_context_verify != NULL); |
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secp256k1_context_destroy(secp256k1_context_verify); |
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secp256k1_context_verify = NULL; |
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} |
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} |
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Pieter Wuille
9 years ago