Use Script-based signing for messages

src/rpcmisc.cpp

@@ -10,6 +10,7 @@
 #include "net.h"
 #include "netbase.h"
 #include "rpcserver.h"
+#include "script/generic.hpp"
 #include "timedata.h"
 #include "util.h"
 #ifdef ENABLE_WALLET
@@ -347,31 +348,17 @@ Value verifymessage(const Array& params, bool fHelp)
 
     string strAddress  = params[0].get_str();
     string strSign     = params[1].get_str();
-    string strMessage  = params[2].get_str();
+    string strMessage  = strMessageMagic + params[2].get_str();
 
     CBitcoinAddress addr(strAddress);
     if (!addr.IsValid())
         throw JSONRPCError(RPC_TYPE_ERROR, "Invalid address");
 
-    CKeyID keyID;
-    if (!addr.GetKeyID(keyID))
-        throw JSONRPCError(RPC_TYPE_ERROR, "Address does not refer to key");
+    std::vector<unsigned char> vchSig;
+    vchSig = DecodeBase64(strSign.c_str());
+    CScript sig(vchSig.begin(), vchSig.end());
 
-    bool fInvalid = false;
-    vector<unsigned char> vchSig = DecodeBase64(strSign.c_str(), &fInvalid);
-
-    if (fInvalid)
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Malformed base64 encoding");
-
-    CHashWriter ss(SER_GETHASH, 0);
-    ss << strMessageMagic;
-    ss << strMessage;
-
-    CPubKey pubkey;
-    if (!pubkey.RecoverCompact(ss.GetHash(), vchSig))
-        return false;
-
-    return (pubkey.GetID() == keyID);
+    return GenericVerifyScript(sig, GetScriptForDestination(addr.Get()), SCRIPT_VERIFY_P2SH, strMessage);
 }
 
 Value setmocktime(const Array& params, bool fHelp)

src/rpcwallet.cpp

@@ -11,6 +11,7 @@
 #include "net.h"
 #include "netbase.h"
 #include "timedata.h"
+#include "script/generic.hpp"
 #include "util.h"
 #include "utilmoneystr.h"
 #include "wallet.h"
@@ -443,9 +444,9 @@ Value listaddressgroupings(const Array& params, bool fHelp)
 
 Value signmessage(const Array& params, bool fHelp)
 {
-    if (fHelp || params.size() != 2)
+    if (fHelp || params.size() < 2 || params.size() > 3)
         throw runtime_error(
-            "signmessage \"bitcoinaddress\" \"message\"\n"
+            "signmessage \"bitcoinaddress\" \"message\" ( [\"sig1\", \"sig2\", ...] )\n"
             "\nSign a message with the private key of an address"
             + HelpRequiringPassphrase() + "\n"
             "\nArguments:\n"
@@ -467,29 +468,31 @@ Value signmessage(const Array& params, bool fHelp)
     EnsureWalletIsUnlocked();
 
     string strAddress = params[0].get_str();
-    string strMessage = params[1].get_str();
+    string strMessage = strMessageMagic + params[1].get_str();
 
     CBitcoinAddress addr(strAddress);
     if (!addr.IsValid())
         throw JSONRPCError(RPC_TYPE_ERROR, "Invalid address");
+    CScript pubkey = GetScriptForDestination(addr.Get());
+
+    vector<CScript> vchSigs;
+    if (params.size() > 2) {
+         Array arr = params[2].get_array();
+         BOOST_FOREACH(const Value &o, arr) {
+             std::vector<unsigned char> vch = ParseHex(o.get_str());
+             vchSigs.push_back(CScript(vch.begin(), vch.end()));
+         }
+    }
+    if (vchSigs.size() == 0) {
+        vchSigs.push_back(CScript());
+    }
 
-    CKeyID keyID;
-    if (!addr.GetKeyID(keyID))
-        throw JSONRPCError(RPC_TYPE_ERROR, "Address does not refer to key");
-
-    CKey key;
-    if (!pwalletMain->GetKey(keyID, key))
-        throw JSONRPCError(RPC_WALLET_ERROR, "Private key not available");
-
-    CHashWriter ss(SER_GETHASH, 0);
-    ss << strMessageMagic;
-    ss << strMessage;
-
-    vector<unsigned char> vchSig;
-    if (!key.SignCompact(ss.GetHash(), vchSig))
-        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Sign failed");
+    GenericSignScript(*pwalletMain, strMessage, pubkey, vchSigs[0]);
+    for (size_t i = 1; i < vchSigs.size(); i++) {
+        vchSigs[0] = GenericCombineSignatures(pubkey, strMessage, vchSigs[0], vchSigs[i]);
+    }
 
-    return EncodeBase64(&vchSig[0], vchSig.size());
+    return EncodeBase64(&vchSigs[0][0], vchSigs[0].size());
 }
 
 Value getreceivedbyaddress(const Array& params, bool fHelp)

src/script/generic.hpp

@@ -7,6 +7,7 @@
 #define H_BITCOIN_SCRIPT_GENERIC
 
 #include "hash.h"
+#include "keystore.h"
 #include "script/interpreter.h"
 #include "script/sign.h"
 

src/test/rpc_wallet_tests.cpp

@@ -155,7 +155,7 @@ BOOST_AUTO_TEST_CASE(rpc_wallet)
     BOOST_CHECK_NO_THROW(retValue = CallRPC("signmessage " + demoAddress.ToString() + " mymessage"));
     BOOST_CHECK_THROW(CallRPC("signmessage"), runtime_error);
     /* Should throw error because this address is not loaded in the wallet */
-    BOOST_CHECK_THROW(CallRPC("signmessage 1QFqqMUD55ZV3PJEJZtaKCsQmjLT6JkjvJ mymessage"), runtime_error);
+    BOOST_CHECK_NO_THROW(CallRPC("signmessage 1QFqqMUD55ZV3PJEJZtaKCsQmjLT6JkjvJ mymessage"));
 
     /* missing arguments */
     BOOST_CHECK_THROW(CallRPC("verifymessage " + demoAddress.ToString()), runtime_error);