EIP-55 implementation

eip55.py

#!/usr/bin/env python
import unittest
from sha3 import keccak_256

def checksum_encoded(addr):
    checksumed = ''
    hashed = keccak_256(addr.encode('utf-8')).digest().hex()[:40]
    for idx, character in enumerate(addr):
        if character in "0123456789": # Decimal digits should be passed as they are
            checksumed += character
        else:
            to_check = int(hashed[idx], 16)
            if to_check > 7:
                checksumed += character.upper()
            else:
                checksumed += character

    return checksumed

def validate(addr, valid):
    lowercased = addr.lower()
    checksum = checksum_encoded(lowercased)
    return checksum == valid

class TestChecksum(unittest.TestCase):
    def test_checksum(self):
        checksum = checksum_encoded('8da82fcc73cbf2fb1a8c627ec2f0e3fcc3f06748')
        self.assertEqual('8DA82fcc73CBF2fb1a8c627EC2F0E3fCc3F06748', checksum)

    def test_validate(self):
        checksum = checksum_encoded('8da82fcc73cbf2fb1a8c627ec2f0e3fcc3f06748')
        misread = '8DA82fcc73CBF2fb1a8c627EC2F0E3fCc3E06748'
        valid = validate(misread, checksum)
        self.assertFalse(valid)

if __name__ == '__main__':
    unittest.main()