cool address checksum EIP55

Author: Jan Xie

ethereum/tests/test_utils.py

@@ -0,0 +1,21 @@
+import pytest
+from ethereum import utils
+
+def test_add_cool_checksum():
+    addresses = [
+      # All caps
+      '0x52908400098527886E0F7030069857D2E4169EE7',
+      '0x8617E340B3D01FA5F11F306F4090FD50E238070D',
+      # All Lower
+      '0xde709f2102306220921060314715629080e2fb77',
+      '0x27b1fdb04752bbc536007a920d24acb045561c26',
+      # Normal
+      '0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed',
+      '0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359',
+      '0xdbF03B407c01E7cD3CBea99509d93f8DDDC8C6FB',
+      '0xD1220A0cf47c7B9Be7A2E6BA89F429762e7b9aDb',
+    ]
+
+    for addr in addresses:
+        assert utils.add_cool_checksum(addr.lower()) == addr
+        assert utils.check_and_strip_cool_checksum(addr) == utils.normalize_address(addr)

ethereum/utils.py

@@ -136,13 +136,29 @@ def add_checksum(x):
         return x
     return x + sha3(x)[:4]
 
+def add_cool_checksum(addr):
+    addr = normalize_address(addr)
+    addr_hex = encode_hex(addr)
+
+    o = ''
+    h = encode_hex(sha3(addr_hex))
+    for i, c in enumerate(addr_hex):
+        if c in '0123456789':
+            o += c
+        else:
+            o += c.lower() if h[i] in '01234567' else c.upper()
+    return '0x'+o
 
 def check_and_strip_checksum(x):
     if len(x) in (40, 48):
         x = decode_hex(x)
     assert len(x) == 24 and sha3(x[:20])[:4] == x[-4:]
     return x[:20]
 
+def check_and_strip_cool_checksum(addr):
+    assert add_cool_checksum(addr.lower()) == addr
+    return normalize_address(addr)
+
 
 def normalize_address(x, allow_blank=False):
     if is_numeric(x):