IsCanonicalPubKey method in Bitcoin Core source

bool IsCanonicalPubKey(const valtype &vchPubKey) {
    if (vchPubKey.size() < 33)
        return error("Non-canonical public key: too short");
    if (vchPubKey[0] == 0x04) {
        if (vchPubKey.size() != 65)
            return error("Non-canonical public key: invalid length for uncompressed key");
    } else if (vchPubKey[0] == 0x02 || vchPubKey[0] == 0x03) {
        if (vchPubKey.size() != 33)
            return error("Non-canonical public key: invalid length for compressed key");
    } else {
        return error("Non-canonical public key: compressed nor uncompressed");
    }
    return true;
}

1) Public keys must be either 65 or 33 bytes long.
2a) 65 byte long public keys must start with one byte prefix 0x04
2b) 33 byte long public keys must start with one byte prefix 0x02 or 0x03
3) Any other byte sequences can not be treated as public key

amaclin

Posted 2014-08-13T06:32:13.837

Reputation: 5 763

Do you think "Non-canonical public key: compressed nor uncompressed" can cause a wallet to crash? – Emre Kenci – 2014-08-13T13:53:55.287

I am sure - no. This check is for incoming/raw transactions. If the test failed - the client throws away this transaction. As if it not exists at all. – amaclin – 2014-08-13T14:48:50.943

IsCanonicalPubKey method in Bitcoin Core source

Answers