def primitive_root(n):
""" Finds a primitive root modulo n using Gauss's algorithm
and some related facts. """
fact = factorize(n)
if len(fact) == 1:
p, e = fact[0]
if p == 2:
if e <= 2:
return n // 2
return
pr = _primitive_root(p)
if e > 1 and pow(pr, p - 1, p ** 2) == 1:
pr += p
return pr
elif len(fact) == 2:
if fact[0] != (2, 1):
return
p, e = fact[1]
pr = _primitive_root(p)
if e > 1 and pow(pr, p - 1, p ** 2) == 1:
pr += p
if pr % 2 == 0:
pr += p ** e
return pr
def algebras(m_maxs):
"""
Generator for the possible algebras.
Args:
m_maxs: Maximum possible m values given p and d as a tuple e.g. (m, p, d).
Returns:
A 5-tuple ( m, p, d, phi_m, nSlots ) for the algebra.
Usage:
>>> print( '\\n'.join(map(str,algebras( ((24, 5, 2),) ))))
(2, 5, 1, 1, 1)
(4, 5, 1, 2, 2)
(8, 5, 2, 4, 2)
(3, 5, 2, 2, 1)
(6, 5, 2, 2, 1)
(12, 5, 2, 4, 2)
(24, 5, 2, 8, 4)
"""
# Generate the divisors for each max_m
for m_max,p,d in m_maxs:
factors = numth.factorize(m_max)
for mFactors in numth.divisorsFactors(factors):
d_real = d
m = numth.calcDivisor(mFactors)
if m == 1:
continue
phi_m = numth.phi(mFactors)
# Correct for order of p in mod m a.k.a. d
phimFactors = numth.factorize(phi_m)
for e in sorted(numth.divisors(phimFactors)):
if p**e % m == 1:
d_real = e
break
nSlots, r = divmod(phi_m, d_real)
if r != 0:
raise ArithmeticError("Fractional nslots should not exist.")
# SolnObj just a 5-tuple ( m, p, d, phi_m, nSlots )
yield (m,p,d_real,phi_m,nSlots)
def _log_pohlig_hellman(g, a, p):
""" For internal use only - see log() for other purposes.
Finds the discreet logarithm log_g(a) modulo p using the
Pohlig-Hellman algorithm. """
o = order(g, p)
fact = factorize(o)
rems, mods = [], []
for q, e in fact:
d = q ** e
ne = o // d
rem = _log_pohlig_hellman_pp(pow(g, ne, p), pow(a, ne, p), p, q, e)
rems.append(rem)
mods.append(d)
return solve_mult_cong(zip(rems, mods))[0]
def pow_mod(a, e, n):
""" Computes a^e mod n using Carmichael's function. """
fact = factorize(n)
rems, mods = [], []
for p, exp in fact:
d = p ** exp
mods.append(d)
if a % p == 0 and e > exp:
rems.append(0)
else:
rems.append(pow(a % d, e % carmichael(d), d))
if len(rems) > 1:
R = solve_mult_cong(zip(rems, mods))[0]
else:
R = rems[0]
return R
def solve_quadr(a, b, c, n):
""" Finds the solutions of the congruence aX^2 + bX + c = 0 (mod n). """
rems, mods = [], []
for q, e in factorize(n):
rem = _solve_quadr_pk(a, b, c, q, e)
if not rem:
rems = []
break
rems.append(rem)
mods.append(q ** e)
if len(rems) > 1:
sols = [solve_mult_cong(zip(rs, mods))[0] for rs in product(*rems)]
elif len(rems) == 1:
sols = rems[0]
else:
sols = []
return sols
def root(n, a, m):
""" Finds the solutions of the equation x^n = a (mod m). """
rems, mods = [], []
for q, e in factorize(m):
if q == 2 and e > 2:
r = _root_p2(n, a, e)
else:
r = _root_pp(n, a, q, e)
if r is None:
return
rems.append(r)
mods.append(q ** e)
if len(rems) > 1:
sols = [solve_mult_cong(zip(rs, mods))[0] for rs in product(*rems)]
else:
sols = rems[0]
return sols
def parsePrimeRange(rangeStr):
"""
Parses the ranges and numbers given to it, but only of primes.
Args:
rangeStr: a string e.g. '2-5,7,10-11'
Returns:
A list of prime numbers to try out.
Usage:
>>> parsePrimeRange('2-5,7,10-11')
[2, 3, 5, 7, 11]
"""
p_prime = list(\
filter(lambda x: numth.factorize(x)[x] == 1, \
parseRange(rangeStr))\
)
if len(p_prime) == 0:
raise argparse.ArgumentTypeError("No primes found in range given.")
return p_prime
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="")
parser.add_argument("-p", type=parsePrimeRange, default="2",
help="Prime number for plaintext space.")
parser.add_argument("-d", type=parseRange, default="1",
help="How many coefficients in a slot (the order of p in ZmStar).")
parser.add_argument("--self-test", action="store_true",
help="Run doctest on itself.")
args = parser.parse_args()
# Run doctest instead of normal operation
if args.self_test:
import doctest
print(doctest.testmod())
exit(0)
# Generator for m_max(s)
m_maxs = [ (p**d - 1, p, d) for p in args.p for d in args.d ]
# SolnObj just a 5-tuple ( m, p, d, phi_m, nSlots )
solns = sorted( algebras(m_maxs) )
m_max = max(m_maxs)
minWidths = [ math.ceil(math.log10(t)) for t in m_max ]
minWidths.append(
math.ceil(math.log10(numth.phi(numth.factorize(m_max[0])))))
minWidths.append(minWidths[-1])
printTable( ('m','p','d','phi(m)','nSlots'), solns, minWidths)
