Encode chr(0) in pyelliptic.eccblind

Author: g1itch

src/pyelliptic/eccblind.py

@@ -150,7 +150,7 @@ def _ec_point_serialize(self, point):
                 # padding manually
                 bx = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(x))
                 OpenSSL.BN_bn2bin(x, bx)
-                out = bx.raw.rjust(l_, chr(0))
+                out = bx.raw.rjust(l_, chr(0).encode())
             return pack(EC, y_byte, out)
 
         finally:
@@ -180,7 +180,7 @@ def _bn_serialize(self, bn):
         except AttributeError:
             o = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(bn))
             OpenSSL.BN_bn2bin(bn, o)
-            return o.raw.rjust(l_, chr(0))
+            return o.raw.rjust(l_, chr(0).encode())
 
     def _bn_deserialize(self, data):
         """Make a BigNum out of string"""