This new cipher is a Caesar Cipher with a twist. This cryptosystem will operate on bytes (8-bits): for an alphabet of 256 values (0–255). Text will be represented as ASCII (A is represented by hex 0x41, etc.). Instead of shift, Exclusive OR (XOR) is used. Because of this, encryption and decryption are the same operation. Your agents have found that the following Python 3 encryption algorithm (C and Java given later): import base64 00 von AWNA def encode(text): return base64.b64encode(text) def decode(text): return base64.b64decode(text) def encrypt(cleartext, key): to return = bytearray(len(cleartext)) for i in range( len(cleartext)): to_return[i] = cleartext[i] * key return bytes (to_return) Analysis of the encryption function shows that it can output non-printable characters (confirm this for yourself), therefore all output is encoded using Base64 Encoding using the encode and decode functions. For example, the string "test" encrypted with the key 0x80 (128 decimal) is: 1 2 print(encode(encrypt(b"test", 0x80))) b'90Xz9A==" We can verify that encrypting 90X29A== with the key 0x80 results is "test": i 2 print(encrypt(decode("90Xz9A=="), 0x80)); b'test' Your spies have also converted this code to a Java class and C code.