📅 Commit Sat, 18 Sep 2021 19:01:41

✨ otp_crib_drag in cypto extras
✨ ChepyLite class
🔍️ more lazy imports
✅ tests added/updated

TODO

@@ -47,6 +47,7 @@ Misc:
   ☐ cyberchef recipe to chepy recipe converter
 
 Archive:
+  ✔ crib dragging @project(New ideas)
   ✔ xor data with key @project(Utility)
   ✔ strip ansi color codes @project(New ideas)
   ✔ build pyinstaller artifact for osx, linux, windows @project(Github Actions)

chepy/extras/crypto_extras.py

@@ -1,6 +1,6 @@
 import json
-from typing import Iterator, Dict
-from binascii import hexlify
+from typing import Iterator, Dict, List, Union
+from binascii import hexlify, unhexlify
 from itertools import cycle
 from urllib.request import urlopen
 from Crypto.PublicKey import RSA
@@ -77,12 +77,12 @@ def xor_bruteforce_multi(
         }
 
 
-def xor_two_files(file1: str, file2: str) -> bytes: # pragma: no cover
+def xor_two_files(file1: str, file2: str) -> bytes:  # pragma: no cover
     # TODO
     pass
 
 
-def xor(data: bytes, key: bytes) -> bytes: # pragma: no cover
+def xor(data: bytes, key: bytes) -> bytes:  # pragma: no cover
     """XOR data with a hex key
 
     Args:
@@ -97,3 +97,33 @@ def xor(data: bytes, key: bytes) -> bytes: # pragma: no cover
         b'c2dea0b1c5'
     """
     return hexlify(bytes(a ^ b for a, b in zip(data, cycle(key))))
+
+
+def one_time_pad_crib(
+    cipherText1: Union[bytes, str], cipherText2: Union[bytes, str], crib: bytes
+) -> List[str]:
+    """One time pad crib attack.
+
+    Args:
+        cipherText1 (Union[bytes, str]): Cipher text 1 as hex
+        cipherText2 (Union[bytes, str]): Cipher text 2 as hex
+        crib (bytes): Crib (known text) as bytes
+
+    Returns:
+        List[str]: List of possible plaintexts
+    """
+    cipherText1 = unhexlify(cipherText1)
+    cipherText2 = unhexlify(cipherText2)
+    xored = bytearray(a ^ b for a, b in zip(cipherText1, cipherText2))
+    hold = []
+    for offset in range(0, len(xored) - len(crib) + 1):
+        piece = xored[offset : offset + len(crib)]
+        piece = bytearray(a ^ b for a, b in zip(crib, piece))
+        if all(32 <= c <= 126 for c in piece):
+            piece = (
+                ("." * offset)
+                + piece.decode()
+                + ("." * (len(xored) - len(crib) - offset))
+            )
+            hold.append(piece)
+    return hold

chepy/lite.py

@@ -1,9 +1,37 @@
 from .modules.aritmeticlogic import AritmeticLogic
+from .modules.compression import Compression
+from .modules.dataformat import DataFormat
+from .modules.datetimemodule import DateTime
+from .modules.encryptionencoding import EncryptionEncoding
+from .modules.extractors import Extractors
+from .modules.hashing import Hashing
+from .modules.language import Language
+from .modules.links import Links
+from .modules.multimedia import Multimedia
+from .modules.networking import Networking
+from .modules.other import Other
+from .modules.publickey import Publickey
+from .modules.search import Search
+from .modules.utils import Utils
 
 class ChepyLite(
-    AritmeticLogic
+    AritmeticLogic,
+    Compression,
+    DataFormat,
+    DateTime,
+    EncryptionEncoding,
+    Extractors,
+    Hashing,
+    Language,
+    Links,
+    Networking,
+    Other,
+    Publickey,
+    Search,
+    Utils,
 ):
-    """Chepy Lite class. Chepy lite is a lightweight version of Chepy which uses 
-    very little outside dependencies making it much faster to load than Chepy core.
+    """Chepy Lite class. Chepy lite is a lightweight version of Chepy which offers 
+    most of the core functionalities of Chepy, but without any extensions or extra 
+    modules. This is so that Chepy load time can be faster.
     """
     pass

chepy/modules/utils.py

@@ -1,9 +1,10 @@
+import lazy_import
 import difflib
 from collections import OrderedDict
 from typing import TypeVar, Union
 
 import chepy.modules.internal.colors as _int_colors
-import exrex
+exrex = lazy_import.lazy_module("exrex")
 import pydash
 import regex as re
 

tests/test_extras/test_crypto_extras.py

@@ -1,2 +1,12 @@
-from chepy.extras.crypto_extras import *
+from chepy.extras.crypto_extras import one_time_pad_crib
 
+
+def test_one_time_pad_crib():
+    assert (
+        one_time_pad_crib(
+            "51060328ac104b70881b267fb254d7914948e697aff2ce1c07c91c51b4ff2a172b6477c7e006",
+            "560b032eb6481826df19237ce403d7c34c4db194fff59a4f559a4d09b6fa72157a642797e31a",
+            b"a" * 38,
+        )[0]
+        == "flag{9276cdb76a3dd6b1f523209cd9c0a11b}"
+    )