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--- ic:labs:04 [2023/10/01 23:21]
razvan.smadu [SPN 1 (3p)]
+++ ic:labs:04 [2023/10/09 23:21] (current)
razvan.smadu
@@ Line 3: / Line 3: @@
 Prezentarea PowerPoint pentru acest laborator poate fi găsită [[https://drive.google.com/file/d/1mjbkxFqYNB-lRRXGAhsdh1vK9nwbnDuS/view?usp=sharing|aici]].
-Puteți lucra acest laborator folosind și platforma Google Colab, accesând [[https://colab.research.google.com/drive/1rxZ9eyzMXqq3NDia22suPO_1QPAb5o0C?usp=sharing
+Puteți lucra acest laborator folosind platforma Google Colab, accesând [[https://colab.research.google.com/github/ACS-IC-labs/IC-labs/blob/main/labs/lab04/lab4.ipynb
 |acest]] link.
+<hidden>
 <spoiler Click pentru a vedea utils.py>
 <file python utils.py>
 import base64
+from typing import Generator
-# CONVERSION FUNCTIONS
-def _chunks(string, chunk_size):
-    for i in range(0, len(string), chunk_size):
-        yield string[i:i+chunk_size]
-# THIS ONE IS NEW
+def _pad(data: str, size: int) -> str:
-def byte_2_bin(bval):
+    reminder = len(data) % size
-    """
+    if reminder != 0:
-      Transform a byte (8-bit) value into a bitstring
+        data = "0" * (size - reminder) + data
+    return data
+def _chunks(data: str, chunk_size: int) -> Generator[str, None, None]:
+    data = _pad(data, chunk_size)
+    for i in range(0, len(data), chunk_size):
+        yield data[i : i + chunk_size]
+def _hex(data: int) -> str:
+    return format(data, "02x")
+# Conversion functions
+def byte_2_bin(bval: int) -> str:
+    """Converts a byte value to a binary string.
+    Args:
+        bval (int):
+            The byte value to be converted. It should be an integer between
+and 255.
+    Returns:
+        str: The binary string representation of the byte value, where each bit
+        is encoded as a character. The result has a fixed length of 8 characters
+        and is padded with leading zeros if necessary.
+    Examples:
+        >>> byte_2_bin(72)
+        '01001000'
+        >>> byte_2_bin(66)
+        '01000010'
     """
     return bin(bval)[2:].zfill(8)
-def _hex(x):
-    return format(x, '02x')
-def hex_2_bin(data):
+def hex_2_bin(data: str) -> str:
-    return ''.join(f'{int(x, 16):08b}' for x in _chunks(data, 2))
+    """Converts a hexadecimal string to a binary representation.
-def str_2_bin(data):
+    Args:
-    return ''.join(f'{ord(c):08b}' for c in data)
+        data (str): The hexadecimal string to be converted. It should have an
+            even number of characters and only contain valid hexadecimal digits
+            (0-9, A-F, a-f).
-def bin_2_hex(data):
+    Returns:
-    return ''.join(f'{int(b, 2):02x}' for b in _chunks(data, 8))
+        str: The binary representation of the hexadecimal string, where each
+            pair of hexadecimal digits is encoded as an 8-bit binary number.
-def str_2_hex(data):
+    Examples:
-    return ''.join(f'{ord(c):02x}' for c in data)
+        >>> hex_2_bin("01abcd")
+        '000000011010101111001101'
+        >>> hex_2_bin("0a")
+        '00001010'
+    """
+    return "".join(f"{int(x, 16):08b}" for x in _chunks(data, 2))
-def bin_2_str(data):
-    return ''.join(chr(int(b, 2)) for b in _chunks(data, 8))
-def hex_2_str(data):
+def bin_2_hex(data: str) -> str:
-    return ''.join(chr(int(x, 16)) for x in _chunks(data, 2))
+    """Converts a binary string to a hexadecimal representation.
-# XOR FUNCTIONS
+    Args:
-def strxor(a, b):  # xor two strings, trims the longer input
+        data (str): The binary string to be converted. It should have a multiple
-    return ''.join(chr(ord(x) ^ ord(y)) for (x, y) in zip(a, b))
+            of 8 characters and only contain valid binary digits (0 or 1).
-def bitxor(a, b):  # xor two bit-strings, trims the longer input
+    Returns:
-    return ''.join(str(int(x) ^ int(y)) for (x, y) in zip(a, b))
+        str: The hexadecimal representation of the binary string, where each
+            group of 8 binary digits is encoded as a pair of hexadecimal digits.
-def hexxor(a, b):  # xor two hex-strings, trims the longer input
+    Examples:
-    return ''.join(_hex(int(x, 16) ^ int(y, 16)) for (x, y) in zip(_chunks(a, 2), _chunks(b, 2)))
+        >>> bin_2_hex("000000011010101111001101")
+        '01abcd'
+        >>> bin_2_hex("00001010")
+        '0a'
+    """
+    return "".join(f"{int(b, 2):02x}" for b in _chunks(data, 8))
-# BASE64 FUNCTIONS
-def b64decode(data):
-    return bytes_to_string(base64.b64decode(string_to_bytes(data)))
-def b64encode(data):
+def str_2_bin(data: str) -> str:
+    """Converts a string to a binary representation.
+    Args:
+        data (str): The string to be converted.
+    Returns:
+        str: The binary representation of the string, where each character is
+            encoded as an 8-bit binary number.
+    Examples:
+        >>> str_2_bin("Hello")
+        '0100100001100101011011000110110001101111'
+        >>> str_2_bin("IC")
+        '0100100101000011'
+    """
+    return "".join(f"{ord(c):08b}" for c in data)
+def bin_2_str(data: str) -> str:
+    """Converts a binary string to a string.
+    Args:
+        data (str): The binary string to be converted. It should have a multiple
+            of 8 characters and only contain valid binary digits (0 or 1).
+    Returns:
+        str: The string representation of the binary string, where each group
+            of 8 binary digits is decoded as a character.
+    Examples:
+        >>> bin_2_str("0100100001100101011011000110110001101111")
+        'Hello'
+        >>> bin_2_str("0100100101000011")
+        'IC'
+    """
+    return "".join(chr(int(b, 2)) for b in _chunks(data, 8))
+def str_2_hex(data: str) -> str:
+    """Converts a string to a hexadecimal representation.
+    Args:
+        data (str): The string to be converted.
+    Returns:
+        str: The hexadecimal representation of the string, where each character
+            is encoded as a pair of hexadecimal digits.
+    Examples:
+        >>> str_2_hex("Hello")
+        '48656c6c6f'
+        >>> str_2_hex("IC")
+        '4943'
+    """
+    return "".join(f"{ord(c):02x}" for c in data)
+def hex_2_str(data: str) -> str:
+    """Converts a hexadecimal string to a string.
+    Args:
+        data (str): The hexadecimal string to be converted. It should have an
+            even number of characters and only contain valid hexadecimal digits
+            (0-9, A-F, a-f).
+    Returns:
+        str: The string representation of the hexadecimal string, where each
+            pair of hexadecimal digits is decoded as a character.
+    Examples:
+        >>> hex_2_str("48656c6c6f")
+        'Hello'
+        >>> hex_2_str("4943")
+        'IC'
+    """
+    return "".join(chr(int(x, 16)) for x in _chunks(data, 2))
+# XOR functions
+def strxor(operand_1: str, operand_2: str) -> str:
+    """Performs a bitwise exclusive OR (XOR) operation on two strings.
+    Args:
+        operand_1 (str): The first string to be XORed.
+        operand_2 (str): The second string to be XORed.
+    Returns:
+        str: The result of the XOR operation on the two strings, where each
+            character is encoded as an 8-bit binary number. The result has
+            the same length as the shorter input string.
+    Examples:
+        >>> strxor("Hello", "IC")
+        '\\x01&'
+        >>> strxor("secret", "key")
+        '\\x18\\x00\\x1a'
+    """
+    return "".join(chr(ord(x) ^ ord(y)) for (x, y) in zip(operand_1, operand_2))
+def bitxor(operand_1: str, operand_2: str) -> str:
+    """Performs a bitwise exclusive OR (XOR) operation on two bit-strings.
+    Args:
+        operand_1 (str): The first bit-string to be XORed. It should only
+            contain valid binary digits (0 or 1).
+        operand_2 (str): The second bit-string to be XORed. It should only
+            contain valid binary digits (0 or 1).
+    Returns:
+        str: The result of the XOR operation on the two bit-strings, where each
+            bit is encoded as a character. The result has the same length as
+            the shorter input bit-string.
+    Examples:
+        >>> bitxor("01001000", "01000010")
+        '00001010'
+        >>> bitxor("10101010", "00110011")
+        '10011001'
+    """
+    return "".join(str(int(x) ^ int(y)) for (x, y) in zip(operand_1, operand_2))
+def hexxor(operand_1: str, operand_2: str) -> str:
+    """Performs a bitwise exclusive OR (XOR) operation on two hexadecimal
+    strings.
+    Args:
+        operand_1 (str): The first hexadecimal string to be XORed. It should
+            have an even number of characters and only contain valid hexadecimal
+            digits (0-9, A-F, a-f).
+        operand_2 (str): The second hexadecimal string to be XORed. It should
+            have an even number of characters and only contain valid
+            digits (0-9, A-F, a-f).
+    Returns:
+        str: The result of the XOR operation on the two hexadecimal strings,
+            where each pair of hexadecimal digits is encoded as a pair of
+            hexadecimal digits. The result has the same length as the shorter
+            input hexadecimal string.
+    Examples:
+        >>> hexxor("48656c6c6f", "42696e67")
+        '0a0c020b'
+        >>> hexxor("736563726574", "6b6579")
+        '18001a'
+    """
+    return "".join(
+        _hex(int(x, 16) ^ int(y, 16))
+        for (x, y) in zip(_chunks(operand_1, 2), _chunks(operand_2, 2))
+    )
+# Python3 'bytes' functions
+def bytes_to_string(bytes_data: bytearray | bytes) -> str:
+    """Converts a byte array or a byte string to a string.
+    Args:
+        bytes_data (bytearray | bytes): The byte array or the byte string to be
+            converted. It should be encoded in Latin-1 format.
+    Returns:
+        str: The string representation of the byte array or the byte string,
+            decoded using Latin-1 encoding.
+    Examples:
+        >>> bytes_to_string(b'Hello')
+        'Hello'
+        >>> bytes_to_string(bytearray(b'IC'))
+        'IC'
+    """
+    return bytes_data.decode(encoding="raw_unicode_escape")
+def string_to_bytes(string_data: str) -> bytes:
+    """Converts a string to a byte string.
+    Args:
+        string_data (str): The string to be converted.
+    Returns:
+        bytes: The byte string representation of the string, encoded using
+        Latin-1 encoding.
+    Examples:
+        >>> string_to_bytes('Hello')
+        b'Hello'
+        >>> string_to_bytes('IC')
+        b'IC'
+    """
+    return string_data.encode(encoding="raw_unicode_escape")
+# Base64 functions
+def b64encode(data: str) -> str:
+    """Encodes a string to base64.
+    Parameters:
+        data (str): The string to be encoded.
+    Returns:
+        str: The base64 encoded string, using Latin-1 encoding.
+    Examples:
+        >>> b64encode("Hello")
+        'SGVsbG8='
+        >>> b64encode("IC")
+        'SUM='
+    """
     return bytes_to_string(base64.b64encode(string_to_bytes(data)))
-# PYTHON3 'BYTES' FUNCTIONS
-def bytes_to_string(bytes_data):
-    return bytes_data.decode()  # default utf-8
-def string_to_bytes(string_data):
+def b64decode(data: str) -> str:
-    return string_data.encode()  # default utf-8
+    """Decodes a base64 encoded string.
+    Args:
+        data (str): The base64 encoded string to be decoded. It should only
+            contain valid base64 characters (A-Z, a-z, 0-9, +, /, =).
+    Returns:
+        str: The decoded string, using Latin-1 encoding.
+    Examples:
+        >>> b64decode("SGVsbG8=")
+        'Hello'
+        >>> b64decode("SUM=")
+        'IC'
+    """
+    return bytes_to_string(base64.b64decode(string_to_bytes(data)))
 </file>
 </spoiler>
@@ Line 168: / Line 434: @@
-def permute4_32(s: str) -> str:
-    """Perform a permutatation by shifting all bits 4 positions right.
-    Args:
-        s (str): The input is assumed to be a 32-bit bitstring.
-    Raises:
-        TypeError: Expected input to be a string.
-        ValueError: Expected input to have length 32.
-    Returns:
-        str: The permuted string by shifting all bits 4 positions right.
-    """
-    if not isinstance(s, str):
-        raise TypeError(
-            f"Invalid type for the input. Expected `str`, but got `{type(s)}`."
-        )
-    if len(s) != 32:
-        raise ValueError(
-            f"Invalit input length. Expected to be 32, but got {len(s)}."
-        )
-    return s[28:32] + s[0:28]
-def permute_inv4_32(s: str) -> str:
-    """Perform the inverse of permute4_32.
-    Args:
-        s (str): The input is assumed to be a 32-bit bitstring.
-    Raises:
-        TypeError: Expected input to be a string.
-        ValueError: Expected input to have length 32.
-    Returns:
-        str: The permuted string by shifting all bits 4 positions left.
-    """
-    if not isinstance(s, str):
-        raise TypeError(
-            f"Invalid type for the input. Expected `str`, but got `{type(s)}`."
-        )
-    if len(s) != 32:
-        raise ValueError(
-            f"Invalit input length. Expected to be 32, but got {len(s)}."
-        )
-    return s[4:32] + s[0:4]
@@ Line 332: / Line 552: @@
     return y1 + y2
@@ Line 338: / Line 560: @@
     msg = "Hi"
     key = "??"  # Find the key that should replace ??
+    ks = str_2_bin(key)
+    # TODO 1: Find the key in the reduced 2-byte SPN
     xs = str_2_bin(msg)
-    ks = str_2_bin(key)
     ys = spn_1r_reduced_2s(ks, xs)
     print(
-        f"Two y halves of reduced SPN:"
+        "Two y halves of reduced SPN:"
         f" {ys[0:8]} (hex: {bin_2_hex(ys[0:8])}),"
         f" {ys[8:16]} (hex: {bin_2_hex(ys[8:16])})"
@@ Line 351: / Line 576: @@
     msg = "Om"
     key = "????"  # Find the key that should replace ????
-    xs = str_2_bin(msg)
     ks = str_2_bin(key)
+    # TODO 2: Find the key in the full 2-byte SPN
+    xs = str_2_bin(msg)
     ys = spn_1r_full_2s(ks, xs)
     print(
-        f"Two y halves of full SPN (2 bytes):"
+        "Two y halves of full SPN (2 bytes):"
         f" {ys[0:8]} (hex: {bin_2_hex(ys[0:8])}),"
         f" {ys[8:16]} (hex: {bin_2_hex(ys[8:16])})"
     )
 if __name__ == "__main__":
     main()
 </code>
 </spoiler>
@@ Line 390: / Line 619: @@
 De data aceasta nu se poate executa o cautare brute-force pe toți octeții de XOR. Încercați să atacați câte un S-box pe rând. Gandiți-vă ce biți sunt afectați de fiecare S-box pentru a construi un atac eficient. Ce se întâmplă dacă faceți brute force pe k5 și k6? Puteți să aflați k1?
 </note>
+</hidden>

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ic/labs/04.1696191703.txt.gz · Last modified: 2023/10/01 23:21 by razvan.smadu

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