2012-08-22 22:33:21 +02:00
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//
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// Unit tests for canonical signatures
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#include "json/json_spirit_writer_template.h"
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#include <boost/test/unit_test.hpp>
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#include <openssl/ecdsa.h>
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#include "key.h"
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#include "script.h"
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#include "util.h"
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using namespace std;
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using namespace json_spirit;
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// In script_tests.cpp
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extern Array read_json(const std::string& filename);
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BOOST_AUTO_TEST_SUITE(canonical_tests)
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// OpenSSL-based test for canonical signature (without test for hashtype byte)
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bool static IsCanonicalSignature_OpenSSL_inner(const std::vector<unsigned char>& vchSig)
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{
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if (vchSig.size() == 0)
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return false;
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const unsigned char *input = &vchSig[0];
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ECDSA_SIG *psig = NULL;
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d2i_ECDSA_SIG(&psig, &input, vchSig.size());
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if (psig == NULL)
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return false;
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unsigned char buf[256];
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unsigned char *pbuf = buf;
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unsigned int nLen = i2d_ECDSA_SIG(psig, NULL);
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if (nLen != vchSig.size()) {
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ECDSA_SIG_free(psig);
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return false;
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}
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nLen = i2d_ECDSA_SIG(psig, &pbuf);
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ECDSA_SIG_free(psig);
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return (memcmp(&vchSig[0], &buf[0], nLen) == 0);
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}
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// OpenSSL-based test for canonical signature
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bool static IsCanonicalSignature_OpenSSL(const std::vector<unsigned char> &vchSignature) {
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if (vchSignature.size() < 1)
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return false;
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if (vchSignature.size() > 127)
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return false;
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if (vchSignature[vchSignature.size() - 1] & 0x7C)
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return false;
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std::vector<unsigned char> vchSig(vchSignature);
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vchSig.pop_back();
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if (!IsCanonicalSignature_OpenSSL_inner(vchSig))
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return false;
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return true;
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}
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BOOST_AUTO_TEST_CASE(script_canon)
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{
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Array tests = read_json("sig_canonical.json");
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BOOST_FOREACH(Value &tv, tests) {
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string test = tv.get_str();
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if (IsHex(test)) {
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std::vector<unsigned char> sig = ParseHex(test);
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Only create signatures with even S, and verification mode to check.
To fix a minor malleability found by Sergio Lerner (reported here:
https://bitcointalk.org/index.php?topic=8392.msg1245898#msg1245898)
The problem is that if (R,S) is a valid ECDSA signature for a given
message and public key, (R,-S) is also valid. Modulo N (the order
of the secp256k1 curve), this means that both (R,S) and (R,N-S) are
valid. Given that N is odd, S and N-S have a different lowest bit.
We solve the problem by forcing signatures to have an even S value,
excluding one of the alternatives.
This commit just changes the signing code to always produce even S
values, and adds a verification mode to check it. This code is not
enabled anywhere yet. Existing tests in key_tests.cpp verify that
the produced signatures are still valid.
2012-12-26 21:10:49 +01:00
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BOOST_CHECK_MESSAGE(IsCanonicalSignature(sig, SCRIPT_VERIFY_STRICTENC), test);
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2012-08-22 22:33:21 +02:00
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BOOST_CHECK_MESSAGE(IsCanonicalSignature_OpenSSL(sig), test);
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}
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}
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}
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BOOST_AUTO_TEST_CASE(script_noncanon)
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{
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Array tests = read_json("sig_noncanonical.json");
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BOOST_FOREACH(Value &tv, tests) {
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string test = tv.get_str();
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if (IsHex(test)) {
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std::vector<unsigned char> sig = ParseHex(test);
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Only create signatures with even S, and verification mode to check.
To fix a minor malleability found by Sergio Lerner (reported here:
https://bitcointalk.org/index.php?topic=8392.msg1245898#msg1245898)
The problem is that if (R,S) is a valid ECDSA signature for a given
message and public key, (R,-S) is also valid. Modulo N (the order
of the secp256k1 curve), this means that both (R,S) and (R,N-S) are
valid. Given that N is odd, S and N-S have a different lowest bit.
We solve the problem by forcing signatures to have an even S value,
excluding one of the alternatives.
This commit just changes the signing code to always produce even S
values, and adds a verification mode to check it. This code is not
enabled anywhere yet. Existing tests in key_tests.cpp verify that
the produced signatures are still valid.
2012-12-26 21:10:49 +01:00
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BOOST_CHECK_MESSAGE(!IsCanonicalSignature(sig, SCRIPT_VERIFY_STRICTENC), test);
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2012-08-22 22:33:21 +02:00
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BOOST_CHECK_MESSAGE(!IsCanonicalSignature_OpenSSL(sig), test);
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}
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}
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}
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BOOST_AUTO_TEST_SUITE_END()
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