MUL-1212: GOLOS signing with private key

   * add implementatino golos private_key::sign
   * add test to verify golos signature

multy_core/src/golos/golos_account.cpp

@@ -19,10 +19,19 @@
 #include "wally_core.h"
 #include "wally_crypto.h"
 
+extern "C" {
+#include "libwally-core/src/internal.h"
+}
+#include "libwally-core/src/secp256k1/include/secp256k1.h"
+
 #include <cassert>
 
 #include <string.h>
 
+#define GOLOS_RECOVERY_PARAM_COMPRESSED 4
+#define GOLOS_RECOVERY_PARAM_COMPACT 27
+#define GOLOS_SIGNATURE_SIZE  65
+
 namespace
 {
 using namespace multy_core::internal;
@@ -43,6 +52,26 @@ uint32_t get_chain_index(BlockchainType blockchain_type)
     return blockchain_type.blockchain;
 }
 
+// Check that signature is in canonical format
+// For details please see: bitshares/bitshares1-core#1129
+bool is_canonical_signature(const std::array<unsigned char, GOLOS_SIGNATURE_SIZE>& c )
+{
+    return !(c[1] & 0x80)
+           && !(c[1] == 0 && !(c[2] & 0x80))
+           && !(c[33] & 0x80)
+           && !(c[33] == 0 && !(c[34] & 0x80));
+}
+
+// This extended nonce function is based on Golos implementation
+static int extended_nonce_function( unsigned char *nonce32, const unsigned char *msg32,
+        const unsigned char *key32, const unsigned char* /*algo16*/,
+        void *data, unsigned int /*attempt*/)
+{
+    unsigned int* extra = (unsigned int*) data;
+    (*extra)++;
+    return secp256k1_nonce_function_default(nonce32, msg32, key32, nullptr, nullptr, *extra);
+}
+
 } // namespace
 
 namespace multy_core
@@ -124,10 +153,30 @@ class GolosPrivateKey : public PrivateKey
         return make_clone(*this);
     }
 
-    BinaryDataPtr sign(const BinaryData& /*data*/) const override
+    BinaryDataPtr sign(const BinaryData& data) const override
     {
-        // TODO: implement signing.
-        return nullptr;
+        auto data_hash = do_hash<SHA2, 256>(data);
+
+        std::array<unsigned char, GOLOS_SIGNATURE_SIZE> result;
+        int recovery_id = 0;
+        unsigned int counter = 0;
+        do
+        {
+            secp256k1_ecdsa_signature signature;
+            if (!secp256k1_ecdsa_sign(secp_ctx(), &signature,
+                    data_hash.data(), m_data.data(), extended_nonce_function, &counter, &recovery_id))
+            {
+                THROW_EXCEPTION("Failed to sign with private key.");
+            }
+
+            if (!secp256k1_ecdsa_signature_serialize_compact(secp_ctx(), result.data() + 1, &signature))
+            {
+                THROW_EXCEPTION("Failed to make compact size from signature.");
+            }
+        } while(!is_canonical_signature(result));
+
+        result.begin()[0] = GOLOS_RECOVERY_PARAM_COMPRESSED + GOLOS_RECOVERY_PARAM_COMPACT + recovery_id;
+        return make_clone(as_binary_data(result));
     }
 
     std::string to_string() const override

multy_test/test_golos_account.cpp

@@ -5,15 +5,20 @@
  */
 
 #include "multy_test/serialized_keys_test_base.h"
-#include "multy_core/src/golos/golos_account.h"
 
+
+#include "multy_core/src/golos/golos_account.h"
+#include "multy_core/src/api/key_impl.h"
 #include "multy_core/golos.h"
 
+#include "multy_test/utility.h"
+
 #include "gtest/gtest.h"
 
 namespace
 {
 using namespace multy_core::internal;
+using namespace test_utility;
 const BlockchainType GOLOS_MAINNET{BLOCKCHAIN_GOLOS, GOLOS_NET_TYPE_MAINNET};
 
 const SerializedKeyTestCase GOLOS_KEYS[] =
@@ -112,4 +117,18 @@ INSTANTIATE_TEST_CASE_P(
                 ::testing::Values(GOLOS_MAINNET),
                 ::testing::ValuesIn(GOLOS_KEYS)));
 
+GTEST_TEST(GolosTest, private_key_sign)
+{
+    AccountPtr account;
+    make_account(BLOCKCHAIN_GOLOS, "5Hq2ZdSGZokcgLoNxNGL5kHKi4e3kUUCqorgFK6T6ka7KtSvYLj", reset_sp(account));
+    PrivateKeyPtr prv_key =  account->get_private_key();
+    // binary serialize TX to sign golos private key
+    BinaryDataPtr signature = prv_key->sign(as_binary_data(from_hex("782a3039b478c839e4cb0c941ff4eaeb7df40bdd68bd441afd444b9da763de1269466c1944189"
+            "fb3bb5a0102096d756c7479746573740b70617368616b6c7962696b010000000000000003474f4c4f5300000000")));
+    // signature generated form golos-core
+    ASSERT_EQ(as_binary_data(from_hex(
+            "1f2e6bb028760bacddd31dc9772e63240fd297ee2f9fcd29f3605aeb79f774fa4b7d1b4e6dc4a1cd6fd2d4e08b2ea2758680d6a5b1e49664522f391ff949b70018")),
+            *signature);
+}
+
 } // namespace