some small fixes

CTFs_and_WarGames/2014-ASIS-CTF/crypto_paillier/paillier_my_poc.py

@@ -0,0 +1,49 @@
+import Crypto.Util.number as cry
+import gmpy
+import random
+
+def generate_keys(nbits):
+    p = cry.getPrime(nbits//2)
+    q = cry.getPrime(nbits//2)
+    n = p*q
+    g = n+1
+    l = (p-1)*(q-1)
+    mu = gmpy.invert(((p-1)*(q-1)), n)
+    return (n, g, l, mu)
+
+def encrypt(key, msg, rand):
+    n_sqr = key[0]**2
+    return (pow(key[1], msg, n_sqr)*pow(rand, key[0], n_sqr) ) % n_sqr
+
+def decrypt(key, cipher):
+    return (((pow(cipher, key[2], key[0]*key[0]) - 1)// key[0]) * key[3]) % key[0]
+
+def get_random_number(n):
+    return random.randint(n//2, n*2)
+
+def decrypt2(key, cipher):
+    n_sqr = key.modulus * key.modulus
+    # Remove random factor from the encryption.
+    noise = pow(RANDOM, key.modulus, n_sqr)
+    invnoise = gmpy.invert(noise, n_sqr)
+    normalized = (cipher * invnoise) % n_sqr
+    # The n^2 modulus isn't a hard case of the discrete logarithm problem.
+    return ((normalized-1)//key.modulus) // ((key.generator-1)//key.modulus)
+
+def paillier_poc():
+    N_BITS = 1024
+    MSG = 1337
+
+    key = generate_keys(N_BITS)
+    rand = get_random_number(N_BITS)
+
+    cipher = encrypt(key, MSG, rand)
+    decipher = decrypt(key, cipher)
+
+    print("The message is {}\n".format(MSG))
+    print("The cipher is {}\n".format(cipher))
+    print("The decipher is {}\n".format(decipher))
+
+if __name__ == '__main__':
+    paillier_poc()
+

Cryptography/paillier/paillier_my_poc.py

@@ -0,0 +1,49 @@
+import Crypto.Util.number as cry
+import gmpy
+import random
+
+def generate_keys(nbits):
+    p = cry.getPrime(nbits//2)
+    q = cry.getPrime(nbits//2)
+    n = p*q
+    g = n+1
+    l = (p-1)*(q-1)
+    mu = gmpy.invert(((p-1)*(q-1)), n)
+    return (n, g, l, mu)
+
+def encrypt(key, msg, rand):
+    n_sqr = key[0]**2
+    return (pow(key[1], msg, n_sqr)*pow(rand, key[0], n_sqr) ) % n_sqr
+
+def decrypt(key, cipher):
+    return (((pow(cipher, key[2], key[0]*key[0]) - 1)// key[0]) * key[3]) % key[0]
+
+def get_random_number(n):
+    return random.randint(n//2, n*2)
+
+def decrypt2(key, cipher):
+    n_sqr = key.modulus * key.modulus
+    # Remove random factor from the encryption.
+    noise = pow(RANDOM, key.modulus, n_sqr)
+    invnoise = gmpy.invert(noise, n_sqr)
+    normalized = (cipher * invnoise) % n_sqr
+    # The n^2 modulus isn't a hard case of the discrete logarithm problem.
+    return ((normalized-1)//key.modulus) // ((key.generator-1)//key.modulus)
+
+def paillier_poc():
+    N_BITS = 1024
+    MSG = 1337
+
+    key = generate_keys(N_BITS)
+    rand = get_random_number(N_BITS)
+
+    cipher = encrypt(key, MSG, rand)
+    decipher = decrypt(key, cipher)
+
+    print("The message is {}\n".format(MSG))
+    print("The cipher is {}\n".format(cipher))
+    print("The decipher is {}\n".format(decipher))
+
+if __name__ == '__main__':
+    paillier_poc()
+