El Camel

.gitignore

@@ -0,0 +1 @@
+__pycache__/

decoding_block_modes.py

@@ -0,0 +1,65 @@
+"""
+# Mode of Operation
+
+so uhhh those diagrams are Shit Ass, so with the help of claude i turned it into python.
+"""
+
+from itertools import batched
+
+
+def AES(key, x):
+    "stub"
+    return x
+
+
+def chunk(message: bytes, size: int):
+    return batched(message, size)  # yields tuples of `size` bytes
+
+
+def xor_bytes(a, b):
+    return bytes(x ^ y for x, y in zip(a, b))
+
+
+# --- ECB ---
+def ecb(key, message):
+    "things go in things go out"
+    for block in chunk(message, 16):
+        yield AES(key, block)  # message goes straight in
+
+
+# --- CBC ---
+def cbc(key, message, iv):
+    "y_i = AES(x_i ^ y_{i-1})"
+    prev = iv
+    for block in chunk(message, 16):
+        x_i = xor_bytes(block, prev)  # XOR with previous ciphertext
+        prev = AES(key, x_i)
+        yield prev
+
+
+# --- OFB ---
+def ofb(key, message, iv):
+    "keystream s evolves on itself, we yield y_i = x_i ^ s_i"
+    keystream = iv
+    for block in chunk(message, 16):
+        keystream = AES(key, keystream)  # encrypt previous *keystream*
+        yield xor_bytes(block, keystream)
+        # keystream feeds back, independent of ciphertext
+
+
+# --- CFB ---
+def cfb(key, message, iv):
+    "difference to OFB is that the y_i is coming back instead of s_i"
+    prev = iv
+    for block in chunk(message, 16):
+        keystream = AES(key, prev)  # encrypt previous ciphertext
+        prev = xor_bytes(block, keystream)
+        yield prev  # ciphertext feeds back, not keystream
+
+
+# --- CTR ---
+def ctr(key, message, nonce):
+    "ts is so easy to understand in python"
+    for i, block in enumerate(chunk(message, 16)):
+        x_i = nonce + i.to_bytes(8)  # counter, message never touches AES
+        yield xor_bytes(block, AES(key, x_i))  # WHATTTTT NO FUCKING WAY

elgamal.py

@@ -0,0 +1,50 @@
+import math
+
+
+class Elgamal:
+    def __init__(self, p: int, alpha: int, d: int) -> None:
+        "contract: p is prime, and"
+        if not 0 <= alpha < p or math.gcd(alpha, p) != 1:
+            # set Z*_n is all i [0, n) st gcd(i, n) = 1, if n is prime thats jus the whole thing
+            raise ValueError()
+        if not 2 <= d <= p - 2:
+            raise ValueError()
+        self.p, self.alpha, self.d = p, alpha, d
+        self.beta = pow(alpha, d, p)
+
+    @property
+    def pubkey(self):
+        return (self.p, self.alpha, self.beta)
+
+    @property
+    def privkey(self):
+        return self.d
+
+    def sig_gen(self, x: int, ke: int) -> tuple[int, int]:
+        if not 2 <= ke <= self.p - 2 or math.gcd(ke, self.p - 1) != 1:
+            raise ValueError()
+        r = pow(self.alpha, ke, self.p)
+        kei = pow(ke, -1, self.p - 1) # mod p - 1 
+        s = ((x - self.d * r) * kei) % (self.p - 1)
+        return r, s
+
+    @staticmethod
+    def sig_verify(x: int, rs: tuple[int, int], pab: tuple[int, int, int]) -> bool:
+        r, s = rs
+        p, alpha, beta = pab
+        t = (pow(beta, r, p) * pow(r, s, p)) % p
+        return (t - pow(alpha, x, p)) % p == 0
+
+
+def main():
+    bob = Elgamal(29, 2, 12)
+    assert bob.beta % 29 == 7
+
+    r, s = bob.sig_gen(26, 5)
+    assert r % 29 == 3, f"{r = }"
+    assert s % 28 == 26, f"{s = }"
+    assert Elgamal.sig_verify(26, (r, s), bob.pubkey)
+
+
+if __name__ == "__main__":
+    main()

lw2.py

@@ -69,9 +69,12 @@ def theREALsmx(x, e, n):
 
 
 def realest(x=None, y=None, n=None):
-    x = x or random.randint(-10e9, 10e9)
-    y = y or random.randint(-10e9, 10e9)
-    n = n or random.randint(2, 10e9)
+    # no way
+    m10e9 = int(-10*10**9)
+    p10e9 = int(10*10**9)
+    x = x or random.randint(m10e9, p10e9)
+    y = y or random.randint(m10e9, p10e9)
+    n = n or random.randint(2, p10e9)
     # print(x, y, n)
     if y < 0:
         try:

lw3.py

@@ -1,4 +1,4 @@
-from proto_rsa import LdaRsahh
+from proto_rsa import LdaRSA
 
 
 def e1():
@@ -18,16 +18,16 @@ def e2():
 
 
 def e3():
-    a = LdaRsahh(p=251, q=191, e=65537).enc(26729)
+    a = LdaRSA(p=251, q=191, e=65537).enc(26729)
 
-    b = LdaRsahh(p=233, q=151, d=9473).dec(29600)
+    b = LdaRSA(p=233, q=151, d=9473).dec(29600)
 
     return a, b
 
 
 def e4():
     C = 412589464
-    M = LdaRsahh(p=81401, q=27109, e=65537).dec(C)
+    M = LdaRSA(p=81401, q=27109, e=65537).dec(C)
     return dec_ascii(M)
 
 

proto_dhke.py

@@ -0,0 +1,28 @@
+class Person:
+    def __init__(self, p: int, g: int, k: int):
+        self.p, self.g, self.k = p, g, k
+        self.s = None
+
+    def public_key(self, recieved: int | None = None) -> int:
+        return pow(recieved or self.g, self.k, self.p)
+
+    def recieve_public_key(self, K: int) -> int:
+        self.s = self.public_key(K)
+        return self.s
+
+
+def main():
+    p = 23
+    g = 5
+    alice = Person(p, g, 4)
+    bob = Person(p, g, 3)
+    assert (
+        alice.recieve_public_key(bob.public_key())
+        == bob.recieve_public_key(alice.public_key())
+        == 18
+    )
+
+
+if __name__ == "__main__":
+    main()
+    print("done")

proto_rsa.py

@@ -7,25 +7,35 @@ def inv(a: int, n: int):
     return pow(a, -1, n)
 
 
-class LdaRsahh:
+class LdaRSA:
     def __init__(
         self,
         p: int,
         q: int,
-        d: int | None = None,
+        *,
         e: int | None = None,
+        d: int | None = None,
         ln_ops: Callable[[int, int], int] | None = None,
     ):
+        """
+        p and q is Prime.
+        
+        ln = lcm(p-1,q-1)
+        
+        e needs to be in range (1, ln) and be coprime with ln, and is the public key.
+        
+        d s.t. d*e === 1 mod ln is the private key
+        """
         # operator.mul or math.lcm
         self._lnops: Callable[[int, int], int] = ln_ops or math.lcm
-        self._p, self._q = p, q
+        self.__p, self.__q = p, q
         if d is None and e is None:
-            raise ValueError("at least d or e needs to be fed in")
+            raise ValueError("at least e or d needs to be fed in")
         ln = self.ln
         if e is None:
             e = inv(d, ln)  # type: ignore
-        elif not 1 < e < ln:
-            e %= ln  # bad
+        # elif not 1 < e < ln:
+        #     e %= ln  # bad
         if not 1 < e < ln:
             raise ValueError(f"{e = }, {ln = }, 1 < e < ln not satisfied")
         if math.gcd(e, ln) != 1:
@@ -34,34 +44,28 @@ class LdaRsahh:
             )
         if d is None:
             d = inv(e, ln)
-        self._d, self._e = d, e
+        self.__d, self.__e = d, e
 
     @cached_property
     def n(self):
-        return self._p * self._q
+        return self.__p * self.__q
 
     @cached_property
     def ln(self):
-        return self._lnops((self._p - 1), (self._q - 1))
-
-    # @property
-    # def p(self):
-    #     return self._p
-
-    # @property
-    # def q(self):
-    #     return self._q
+        return self._lnops((self.__p - 1), (self.__q - 1))
 
     @property
     def d(self):
-        return self._d
+        return self.__d
 
     @property
     def e(self):
-        return self._e
+        return self.__e
 
     def enc(self, m: int):
+        "encode message m"
         return pow(m, self.e, self.n)
 
     def dec(self, c: int):
+        "decode encoded msg c"
         return pow(c, self.d, self.n)