Merge pull request #18 from martinholy/base58_decode_fix

Fix: Incorrect output of Base58 decoding.

Author: meherett

hdwallet/libs/base58.py

@@ -67,15 +67,18 @@ def decode(data):
         data = bytes(data, "ascii")
 
     val = 0
-    for (i, c) in enumerate(data[::-1]):
-        val += __base58_alphabet_bytes.find(c) * (__base58_radix ** i)
+    prefix = 0
+    for c in data:
+        val = (val * __base58_radix) + __base58_alphabet_bytes.find(c)
+        if val == 0:
+            prefix += 1
 
     dec = bytearray()
-    while val >= 256:
+    while val > 0:
         val, mod = divmod(val, 256)
         dec.append(mod)
-    if val:
-        dec.append(val)
+
+    dec.extend(bytearray(prefix))
 
     return bytes(dec[::-1])
 

tests/test_base58.py

@@ -7,7 +7,7 @@
 import pytest
 
 from hdwallet.libs.base58 import (
-    check_encode, check_decode, string_to_int
+    check_encode, check_decode, decode, encode, string_to_int
 )
 
 
@@ -29,3 +29,9 @@ def test_base58():
 
     with pytest.raises(TypeError, match="string argument without an encoding"):
         assert string_to_int(str("meherett"))
+
+
+    assert decode("111233QC4") == b'\x00\x00\x00(\x7f\xb4\xcd'
+
+
+    assert encode(decode("111233QC4")) == "111233QC4"