Reorganized

Cryptography/paillier/primes.py

@@ -1,64 +0,0 @@
-import random
-import sys
-
-
-def ipow(a, b, n):
-    """calculates (a**b) % n via binary exponentiation, yielding itermediate
-       results as Rabin-Miller requires"""
-    A = a = long(a % n)
-    yield A
-    t = 1L
-    while t <= b:
-        t <<= 1
-
-    # t = 2**k, and t > b
-    t >>= 2
-
-    while t:
-        A = (A * A) % n
-        if t & b:
-            A = (A * a) % n
-        yield A
-        t >>= 1
-
-
-def rabin_miller_witness(test, possible):
-    """Using Rabin-Miller witness test, will return True if possible is
-       definitely not prime (composite), False if it may be prime."""
-    return 1 not in ipow(test, possible-1, possible)
-
-
-smallprimes = (2,3,5,7,11,13,17,19,23,29,31,37,41,43,
-               47,53,59,61,67,71,73,79,83,89,97)
-
-
-def default_k(bits):
-    return max(64, 2 * bits)
-
-
-def is_probably_prime(possible, k=None):
-    if possible == 1:
-        return True
-    if k is None:
-        k = default_k(possible.bit_length())
-    for i in smallprimes:
-        if possible == i:
-            return True
-        if possible % i == 0:
-            return False
-    for i in xrange(k):
-        test = random.randrange(2, possible - 1) | 1
-        if rabin_miller_witness(test, possible):
-            return False
-    return True
-
-
-def generate_prime(bits, k=None):
-    # bits should be  >= 8
-    k = k or default_k(bits)
-
-    while True:
-        possible = random.randrange(2 ** (bits-1) + 1, 2 ** bits) | 1
-        if is_probably_prime(possible, k):
-            return possible
-