🗓 Sep 21, 2023 10:15:26 PM

✨ version 6.2.0
✨ to/from_base
✨ rotate right and left
🧪 tests added/updated

chepy/__version__.py

@@ -1,2 +1,2 @@
-__version__ = "6.1.0"  # pragma: no cover
+__version__ = "6.2.0"  # pragma: no cover
 __author__ = "@securisec"  # pragma: no cover

chepy/modules/dataformat.py

@@ -10,7 +10,7 @@
 import string
 from random import randint
 from .internal.constants import Encoding
-from .internal.helpers import detect_delimiter
+from .internal.helpers import detect_delimiter, Rotate
 
 yaml = lazy_import.lazy_module("yaml")
 import regex as re
@@ -1839,3 +1839,85 @@ def unicode_replacer(match):
         )
         self.state = escaped_string
         return self
+
+    @ChepyDecorators.call_stack
+    def to_base(self, radix: int = 36) -> DataFormatT:
+        """Convert int to base
+
+        Args:
+            radix (int, optional): Radix. Defaults to 36.
+
+        Returns:
+            Chepy: The Chepy object.
+        """
+        num = self._convert_to_int()
+        if num == 0:
+            self.state = "0"
+            return self
+
+        chars = string.digits + string.ascii_lowercase
+        result = ""
+
+        while num > 0:
+            remainder = num % radix
+            result = chars[remainder] + result
+            num //= radix
+
+        self.state = result
+        return self
+
+    @ChepyDecorators.call_stack
+    def from_base(self, radix: int = 36) -> DataFormatT:
+        """Convert string to int base
+
+        Args:
+            radix (int, optional): Radix. Defaults to 36.
+
+        Returns:
+            Chepy: The Chepy object.
+        """
+        chars = string.digits + string.ascii_lowercase
+        result = 0
+
+        string_num = self._convert_to_str()
+        for char in string_num:
+            result = result * radix + chars.index(char)
+
+        self.state = result
+        return self
+
+    @ChepyDecorators.call_stack
+    def rotate_right(self, radix: int = 1, carry: bool = False) -> DataFormatT:
+        """Rotate right
+
+        Args:
+            radix (int, optional): Radix. Defaults to 1.
+            carry (bool, optional): Carry. Defaults to False.
+
+        Returns:
+            Chepy: The Chepy object.
+        """
+        r = Rotate(self._convert_to_bytes(), radix)
+        if carry:
+            self.state = r.rot_right_carry()
+        else:
+            self.state = r.rot(Rotate.rotate_right)
+        return self
+
+    @ChepyDecorators.call_stack
+    def rotate_left(self, radix: int = 1, carry: bool = False) -> DataFormatT:
+        """Rotate left
+
+        Args:
+            radix (int, optional): Radix. Defaults to 1.
+            carry (bool, optional): Carry. Defaults to False.
+
+        Returns:
+            Chepy: The Chepy object.
+        """
+        r = Rotate(self._convert_to_bytes(), radix)
+        if carry:
+            self.state = r.rotate_left_carry()
+        else:
+            self.state = r.rot(Rotate.rotate_left)
+        return self

chepy/modules/dataformat.pyi

@@ -99,3 +99,7 @@ class DataFormat(ChepyCore):
     def to_messagepack(self: DataFormatT) -> DataFormatT: ...
     def from_messagepack(self: DataFormatT) -> DataFormatT: ...
     def unicode_escape(self: DataFormatT, padding: int = 0, uppercase_hex:bool=False) -> DataFormatT: ...
+    def to_base(self: DataFormatT, radix: int=16) -> DataFormatT: ...
+    def from_base(self: DataFormatT, radix: int=16) -> DataFormatT: ...
+    def rotate_right(self: DataFormatT, radix: int=1, carry: bool=False) -> DataFormatT: ...
+    def rotate_left(self: DataFormatT, radix: int=1, carry: bool=False) -> DataFormatT: ...

chepy/modules/internal/helpers.py

@@ -38,7 +38,61 @@ def detect_delimiter(
         if len(parts) > 1 and all(part.strip() for part in parts):
             return delimiter
 
-    if default_delimiter: # pragma: no cover
+    if default_delimiter:  # pragma: no cover
         return default_delimiter.encode() if is_bytes else default_delimiter
     else:
         return None
+
+
+class Rotate:
+    def __init__(self, data: bytes, radix: int):
+        self.data = data
+        self.radix = radix
+
+    def rot(self, algo):
+        result = []
+        for byte in self.data:
+            b = byte
+            for _ in range(self.radix):
+                b = algo(b)
+            result.append(b)
+        return b"".join([chr(x).encode() for x in result])
+
+    def rot_right_carry(self):
+        result = []
+        carryBits = 0
+
+        amount = self.radix % 8
+        for i in range(len(self.data)):
+            oldByte = self.data[i] & 0xFF  # Ensure it's treated as an unsigned byte
+            newByte = (oldByte >> amount) | carryBits
+            carryBits = (oldByte & ((1 << amount) - 1)) << (8 - amount)
+            result.append(newByte)
+
+        result[0] |= carryBits
+        return b"".join([chr(x).encode() for x in result])
+
+    @staticmethod
+    def rotate_right(b):
+        bit = (b & 1) << 7
+        return (b >> 1) | bit
+
+    @staticmethod
+    def rotate_left(b):
+        bit = (b >> 7) & 1
+        return ((b << 1) | bit) & 0xFF
+
+    def rotate_left_carry(self):
+        result = bytearray(len(self.data))
+        carryBits = 0
+
+        amount = self.radix % 8
+        for i in range(len(self.data) - 1, -1, -1):
+            oldByte = self.data[i]
+            newByte = ((oldByte << amount) | carryBits) & 0xFF
+            carryBits = (oldByte >> (8 - amount)) & ((1 << amount) - 1)
+            result[i] = newByte
+
+        result[-1] |= carryBits
+
+        return b"".join([chr(x).encode() for x in result])

tests/test_ctf.py

@@ -0,0 +1,43 @@
+from chepy import Chepy
+
+"""
+general tests for CTF solvers
+"""
+
+
+def test_csaw_23_breakthevault():
+    assert (
+        Chepy(
+            "5346815611816381158830026000575759913046890410767282609674124748425112753245783703275530777684185849448083"
+        )
+        .to_base(16)
+        .from_hex()
+        .rotate_right(4)
+        .from_base64()
+        .o
+        == b"csawctf{w@11_ST_1s_n0t_n3ce$$@ry}"
+    )
+
+
+def test_hero_v5_heap():
+    key = "c45c60232c9847e2"
+    payload = "kSDIsBFTYa3+aLqEpVLXtspdLse8WclEhbqGLiqvM6k="
+
+    c = (
+        Chepy(payload)
+        .from_base64()
+        .aes_decrypt(key=key, key_format="utf-8", mode="ECB")
+    )
+    assert c.o == b"Hero{D1G_1NT0_J4V4_H34P}"
+
+
+def test_africe_23_own_reality():
+    k = ".__..._..__...._.___._...___._...__.__...__.._._._....__._._._..._...__..____.__._._._._.__.___..__._.__.__.___..__.____.___.___.__.___.._._____.__..._..__._.._.___._...___..__._._____..__..__..___.....__._...__.._._.__.._._.__...._..__._....___.._.__..._...__._....__..._..__.___.__.._._.__.._._..__.._..__..__..__..__...__._._.__...._..__..._..__..__.__..__..__..._..__.._...__...__.__...__.__...._..__.__..__..__...__..__..__.._...__.___._____._"
+    c = Chepy(k).find_replace("\\.", "0").find_replace("_", "1").from_binary()
+    assert c.o == b"battleCTF{Unknown_bits_384eea49b417ee2ff5a13fbdcca6f327}"
+
+
+def test_springforward_23_hours_behind():
+    c = Chepy("vqkk{0vtg_b1um_e1tt_b3tt}")
+    c.rotate_bruteforce().dict_get_items().filter_list("nicc")
+    assert c.o == b"nicc{0nly_t1me_w1ll_t3ll}"

tests/test_dataformat.py

@@ -597,3 +597,28 @@ def test_unicode_escape():
         Chepy(data).unicode_escape().o
         == b"MMMMM\u200c\u200daaaaaaa\u200c\u200dssss\u200c\u200coooooonnnnnCCC\u200c\u200cCCCC"
     )
+
+
+def test_to_base():
+    assert Chepy(0).to_base().o == b"0"
+    assert Chepy(15295865526991442899).to_base(16).o == b"d445d4a7e477d3d3"
+
+
+def test_from_base():
+    assert Chepy("d445d4a7e477d3d3").from_base(16).o == 15295865526991442899
+
+
+def test_rotate_right():
+    assert Chepy("d445d4a7e477d3d3").from_hex().rotate_right(radix=4).o == b"MTMzNw=="
+    assert (
+        Chepy("d445d4a7e477d3d3").from_hex().rotate_right(radix=4, carry=True).o
+        == b"=D]J~G}="
+    )
+
+
+def test_rotate_left():
+    assert Chepy("d445d4a7e477d3d3").from_hex().rotate_left(radix=4).o == b"MTMzNw=="
+    assert (
+        Chepy("d445d4a7e477d3d3").from_hex().rotate_left(radix=4, carry=True).o
+        == b"D]J~G}=="
+    )