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--- ic:labs:03 [2022/10/14 23:59]
razvan.smadu
+++ ic:labs:03 [2023/10/16 20:53] (current)
razvan.smadu
@@ Line 1: / Line 1: @@
 ===== Laboratorul 03 - PRGs =====
-Prezentarea PowerPoint pentru acest laborator poate fi găsită [[https://drive.google.com/file/d/1IfyMkfV6jQDzW5KhS_B6wt_azV31SLjL/view?usp=sharing|aici]].
+Prezentarea PowerPoint pentru acest laborator poate fi găsită [[https://drive.google.com/file/d/1IfyMkfV6jQDzW5KhS_B6wt_azV31SLjL/view?usp=sharing|aici]]. Puteți găsi o scurtă prezentare a noțiunii de avantaje în [[https://drive.google.com/file/d/1F_mtKi0zeAn1xYQs6Wc7IiiVX8ZW6aeG/view?usp=sharing|acest]] PDF.
-Puteți lucra acest laborator folosind și platforma Google Colab, accesând [[https://colab.research.google.com/drive/1dT6VieWJ1QeMLkb0UY3bAuKvTnkRmWBq?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/lab03/lab3.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):
+def _pad(data: str, size: int) -> str:
-    for i in range(0, len(string), chunk_size):
+    reminder = len(data) % size
-        yield string[i:i+chunk_size]
+    if reminder != 0:
+        data = "0" * (size - reminder) + data
+    return data
-def _hex(x):
-    return format(x, '02x')
-def hex_2_bin(data):
+def _chunks(data: str, chunk_size: int) -> Generator[str, None, None]:
-    return ''.join(f'{int(x, 16):08b}' for x in _chunks(data, 2))
+    data = _pad(data, chunk_size)
+    for i in range(0, len(data), chunk_size):
+        yield data[i : i + chunk_size]
-def str_2_bin(data):
-    return ''.join(f'{ord(c):08b}' for c in data)
-def bin_2_hex(data):
+def _hex(data: int) -> str:
-    return ''.join(f'{int(b, 2):02x}' for b in _chunks(data, 8))
+    return format(data, "02x")
-def str_2_hex(data):
-    return ''.join(f'{ord(c):02x}' for c in data)
-def bin_2_str(data):
+# Conversion functions
-    return ''.join(chr(int(b, 2)) for b in _chunks(data, 8))
-def hex_2_str(data):
-    return ''.join(chr(int(x, 16)) for x in _chunks(data, 2))
-# XOR FUNCTIONS
+def hex_2_bin(data: str) -> str:
+    """Converts a hexadecimal string to a binary representation.
-def strxor(a, b):  # xor two strings, trims the longer input
+    Args:
-    return ''.join(chr(ord(x) ^ ord(y)) for (x, y) in zip(a, b))
+        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 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 binary representation of the hexadecimal string, where each
+            pair of hexadecimal digits is encoded as an 8-bit binary number.
-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)))
+        >>> hex_2_bin("01abcd")
+        '000000011010101111001101'
+        >>> hex_2_bin("0a")
+        '00001010'
+    """
+    return "".join(f"{int(x, 16):08b}" for x in _chunks(data, 2))
-# BASE64 FUNCTIONS
-def b64decode(data):
+def bin_2_hex(data: str) -> str:
-    return bytes_to_string(base64.b64decode(string_to_bytes(data)))
+    """Converts a binary string to a hexadecimal representation.
-def b64encode(data):
+    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 hexadecimal representation of the binary string, where each
+            group of 8 binary digits is encoded as a pair of hexadecimal digits.
+    Examples:
+        >>> bin_2_hex("000000011010101111001101")
+        '01abcd'
+        >>> bin_2_hex("00001010")
+        '0a'
+    """
+    return "".join(f"{int(b, 2):02x}" for b in _chunks(data, 8))
+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):
+def b64decode(data: str) -> str:
-    return bytes_data.decode()  # default utf-8
+    """Decodes a base64 encoded string.
-def string_to_bytes(string_data):
+    Args:
-    return string_data.encode()  # default utf-8
+        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>
 ==== Exercițiul 1 (3p) ====
@@ Line 88: / Line 337: @@
 Puteți folosi următorul schelet de cod:
 <code python 'ex1_weak_rng.py'>
+from typing import List, Tuple
 from utils import *
 class WeakRNG:
-    """ Simple class for weak RNG """
+    """Simple class for weak RNG"""
-    def __init__(self):
+    def __init__(self) -> None:
         self.rstate = 0
         self.maxn = 255
@@ Line 101: / Line 352: @@
         self.p = 257
-    def init_state(self, rstate):
+    def init_state(self, rstate: int) -> None:
-        """ Initialise rstate """
+        """Initialise rstate"""
         self.rstate = rstate  # Set this to some value
         self.update_state()
-    def update_state(self):
+    def update_state(self) -> None:
-        """ Update state """
+        """Update state"""
         self.rstate = (self.a * self.rstate + self.b) % self.p
-    def get_prg_byte(self):
+    def get_prg_byte(self) -> int:
-        """ Return a new PRG byte and update PRG state """
+        """Return a new PRG byte and update PRG state"""
         b = self.rstate & 0xFF
         self.update_state()
@@ Line 117: / Line 368: @@
-def main():
+def main() -> None:
     # Initialise weak rng
     wr = WeakRNG()
@@ Line 123: / Line 374: @@
     # Print ciphertext
-    CH = 'a432109f58ff6a0f2e6cb280526708baece6680acc1f5fcdb9523129434ae9f6ae9edc2f224b73a8'
+    CH = "a432109f58ff6a0f2e6cb280526708baece6680acc1f5fcdb9523129434ae9f6ae9edc2f224b73a8"
     print("Full ciphertext in hexa:", CH)
     # Print known plaintext
-    pknown = 'Let all creation'
+    pknown = "Let all creation"
     nb = len(pknown)
     print("Known plaintext:", pknown)
@@ Line 134: / Line 385: @@
     # Obtain first nb bytes of RNG
-    gh = hexxor(pkh, CH[0:nb*2])
+    gh = hexxor(pkh, CH[0 : nb * 2])
     print(gh)
     gbytes = []
     for i in range(nb):
-        gbytes.append(ord(hex_2_str(gh[2*i:2*i+2])))
+        gbytes.append(ord(hex_2_str(gh[2 * i : 2 * i + 2])))
     print("Bytes of RNG: ")
     print(gbytes)
@@ Line 150: / Line 401: @@
     # TODO 4: Print the full plaintext
-    p = ''
+    p = ...
     print("Full plaintext is:", p)
@@ Line 241: / Line 492: @@
 import random
-def get_random_string(n):
+def get_random_string(n: int) -> str:
-    """ Generate random bit string """
+    """Generate random bit string"""
-    return bin(random.getrandbits(n)).lstrip('0b').zfill(n)
+    return bin(random.getrandbits(n)).lstrip("0b").zfill(n)
 </code>
 </note>
@@ Line 253: / Line 504: @@
 </note>
+<file python ex4.py>
+import math
+import random
+from utils import *
+def get_random_string(n: int) -> str:
+    """Generate random bit string"""
+    return bin(random.getrandbits(n)).lstrip("0b").zfill(n)
+def main() -> None:
+    N_RUNS = 100  # the number of runs
+    N_BITS = 1000  # the number of bits to generate
+    # TODO: implement and run the multiple times (e.g., 100) the
+    # statistical tests
+if __name__ == "__main__":
+    main()
+</file>
 ==== Exercițiul 5 - Bonus (2p) ====
@@ Line 272: / Line 546: @@
 Încercați să implementați aceeași funcționalitate folosind OpenSSL. OpenSSL suportă RC4, dar nu și Salsa20. Folosiți ChaCha20 in loc de Salsa20, aceasta fiind o variantă îmbunătățită a algoritmului.
+</hidden>

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ic/labs/03.1665781191.txt.gz · Last modified: 2022/10/14 23:59 by razvan.smadu

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