Initial commit

funga/eth/encoding.py

@@ -0,0 +1,91 @@
+# standard imports
+import logging
+
+# external imports
+import coincurve
+import sha3
+from hexathon import (
+        strip_0x,
+        uniform,
+        )
+
+logg = logging.getLogger(__name__)
+
+
+def private_key_from_bytes(b):
+    return coincurve.PrivateKey(secret=b)
+
+
+def public_key_bytes_to_address(pubk_bytes, result_format='hex'):
+    h = sha3.keccak_256()
+    logg.debug('public key bytes {}'.format(pubk_bytes.hex()))
+    h.update(pubk_bytes[1:])
+    z = h.digest()[12:]
+    if result_format == 'hex':
+        return to_checksum_address(z[:20].hex())
+    elif result_format == 'bytes':
+        return z[:20]
+    raise ValueError('invalid result format "{}"'.format(result_format))
+
+
+def public_key_to_address(pubk, result_format='hex'):
+    pubk_bytes = pubk.format(compressed=False)
+    return public_key_bytes_to_address(pubk_bytes, result_format='hex')
+
+
+def private_key_to_address(pk, result_format='hex'):
+    pubk = coincurve.PublicKey.from_secret(pk.secret)
+    #logg.debug('secret {} '.format(pk.secret.hex()))
+    return public_key_to_address(pubk, result_format)
+
+
+def is_address(address_hex):
+    try:
+        address_hex = strip_0x(address_hex)    
+    except ValueError:
+        return False
+    return len(address_hex) == 40
+
+
+def is_checksum_address(address_hex):
+    hx = None
+    try:
+        hx = to_checksum(address_hex)
+    except ValueError:
+        return False
+    return hx == strip_0x(address_hex)
+
+
+def to_checksum_address(address_hex):
+        address_hex = strip_0x(address_hex)
+        address_hex = uniform(address_hex)
+        if len(address_hex) != 40:
+            raise ValueError('Invalid address length')
+        h = sha3.keccak_256()
+        h.update(address_hex.encode('utf-8'))
+        z = h.digest()
+
+        #checksum_address_hex = '0x'
+        checksum_address_hex = ''
+
+        for (i, c) in enumerate(address_hex):
+            if c in '1234567890':
+                checksum_address_hex += c
+            elif c in 'abcdef':
+                if z[int(i / 2)] & (0x80 >> ((i % 2) * 4)) > 1:
+                    checksum_address_hex += c.upper()
+                else:
+                    checksum_address_hex += c
+
+        return checksum_address_hex
+
+to_checksum = to_checksum_address
+
+ethereum_recid_modifier = 35
+
+def chain_id_to_v(chain_id, signature):
+    v = signature[64]
+    return (chain_id * 2) + ethereum_recid_modifier + v
+
+def chainv_to_v(chain_id, v):
+    return v - ethereum_recid_modifier - (chain_id * 2)