refactor

encdec.py

@@ -1,10 +1,40 @@
 #!/usr/bin/env python3
 
+from binascii import crc_hqx
+from itertools import cycle
 import os
 from pathlib import Path
 from sys import argv
+from sys import stderr
 
-from lib.base import eprint, encrypt, decrypt
+# Structure of pre-encoded payload
+# 8196 | 16      | ...  | 2   |
+# data | version | data | crc |
+
+KEY = Path('./key.bin').read_bytes()
+
+V_OFFSET = 8192
+V_LEN = 16
+CRC_LEN = 2
+
+def eprint(*args, **kwargs):
+    print(*args, **kwargs, file=stderr)
+
+
+def xor(var):
+    return bytes(a ^ b for a, b in zip(var, cycle(KEY)))
+
+
+def decrypt(data):
+    decrypted = xor(data)
+    eprint('version:', decrypted[V_OFFSET:V_OFFSET+V_LEN].decode())
+    return decrypted[:-CRC_LEN]
+
+
+def encrypt(data):
+    encrypted = xor(data)
+    checksum = crc_hqx(encrypted, 0).to_bytes(2, byteorder='little')
+    return encrypted + checksum
 
 
 def usage(info = None):
@@ -17,24 +47,19 @@ def usage(info = None):
 
 
 def main():
-    if len(argv) != 3:
-        usage()
+    if len(argv) == 3:
+        mode = argv[1]
+        file_bytes = Path(argv[2]).read_bytes()
 
-    encdec = argv[1]
-    fname = argv[2]
-    file_bytes = Path(fname).read_bytes()
+        if mode == 'd':
+            os.write(1, decrypt(file_bytes))
+            eprint('Success!')
+            return
 
-    if encdec == 'd':
-        decrypted = decrypt(file_bytes)
-        os.write(1, bytes(decrypted))
-        eprint('Success!')
-        return
-
-    if encdec == 'e':
-        encrypted = encrypt(file_bytes)
-        os.write(1, bytes(encrypted))
-        eprint('Success!')
-        return
+        if mode == 'e':
+            os.write(1, encrypt(file_bytes))
+            eprint('Success!')
+            return
 
     usage()
         

lib/base.py

@@ -1,37 +0,0 @@
-from itertools import cycle
-from pathlib import Path
-from sys import stderr
-from binascii import crc_hqx
-
-# Structure of pre-encoded payload
-# 8196 | 16      | ...  | 2   |
-# data | version | data | crc |
-
-KEY = Path('./key.bin').read_bytes()
-
-V_OFFSET = 8192
-V_LEN = 16
-CRC_LEN = 2
-
-def eprint(*args, **kwargs):
-    print(*args, **kwargs, file=stderr)
-
-
-def xor(var):
-    return bytes(a ^ b for a, b in zip(var, cycle(KEY)))
-
-
-def make_16byte_version(version):
-    return bytes([ord(c) for c in version] + [0] * (16 - len(version)))
-
-
-def decrypt(data):
-    decrypted = xor(data)
-    eprint('version:', decrypted[V_OFFSET:V_OFFSET+V_LEN])
-    return decrypted[:-CRC_LEN]
-
-
-def encrypt(data):
-    encrypted = xor(data)
-    checksum = crc_hqx(encrypted, 0).to_bytes(2, byteorder='little')
-    return encrypted + checksum