verifymessage.cpp

#include <stdio.h>
#include <string>
#include <vector>
using namespace std;

#include "util.h"
#include "base58.h"

bool fTestNet = false;
const string strMessageMagic = "Bitcoin Signed Message:\n"; // from main.cpp

int main(int argc, char *argv[]) {
    if (argc != 4) {
        fprintf(stderr,
            "verifysig <bitcoinaddress> <signature> <message>\n\n"
            "Verify a signed message\n");
        return 255;
    }

    string strAddress  = argv[1];
    string strSign     = argv[2];
    string strMessage  = argv[3];

    CBitcoinAddress addr(strAddress);
    if (!addr.IsValid()) {
        fprintf(stderr, "Invalid address\n");
        return 2;
    }

    CKeyID keyID;
    if (!addr.GetKeyID(keyID)) {
        fprintf(stderr, "Address does not refer to key\n");
        return 3;
    }

    bool fInvalid = false;
    vector<unsigned char> vchSig = DecodeBase64(strSign.c_str(), &fInvalid);

    if (fInvalid) {
        fprintf(stderr, "Malformed base64 encoding\n");
        return 4;
    }

    CHashWriter ss(0);
    ss << strMessageMagic;
    ss << strMessage;

    CKey key;
    if (!key.SetCompactSignature(ss.GetHash(), vchSig)) {
        fprintf(stderr, "Error reading signature\n");
        return 5;
    }

    // 0 is "success" in standard UNIX return codes
    if (key.GetPubKey().GetID() == keyID) {
        printf("pass\n");
        return 0;
    } else {
        printf("fail\n");
        return 1;
    }
}