[Memo] unpad memo correctly

graphenebase/memo.py

@@ -2,7 +2,8 @@
 import hashlib
 from binascii import hexlify, unhexlify
 from Crypto.Cipher import AES
-from .account import PrivateKey, PublicKey
+from graphenebase.account import PrivateKey, PublicKey
+import struct
 
 " This class and the methods require python3 "
 assert sys.version_info[0] == 3, "graphenelib requires python3"
@@ -51,11 +52,17 @@ def init_aes(shared_secret, nonce) :
 
 
 def _pad(s, BS):
-    import struct
     numBytes = (BS - len(s) % BS)
     return s + numBytes * struct.pack('B', numBytes)
 
 
+def _unpad(s, BS):
+    count = int(struct.unpack('B', bytes(s[-1], 'ascii'))[0])
+    if bytes(s[-count::], 'ascii') == count * struct.pack('B', count):
+        return s[:-count]
+    return s
+
+
 def encode_memo(priv, pub, nonce, message) :
     """ Encode a message with a shared secret between Alice and Bob
 
@@ -103,7 +110,7 @@ def decode_memo(priv, pub, nonce, message) :
     " TODO, verify checksum "
     message = cleartext[4:]
     try :
-        return message.decode('utf8').strip()
+        return _unpad(message.decode('utf8'), 16)
     except :
         raise ValueError(message)