def PRandM(r_dprime, r_prime, b, k, m, kappa, use_dabit=True):
"""
r_dprime = random secret integer in range [0, 2^(k + kappa - m) - 1]
r_prime = random secret integer in range [0, 2^m - 1]
b = array containing bits of r_prime
"""
program.curr_tape.require_bit_length(k + kappa)
from .types import sint
if program.use_edabit() and m > 1 and not const_rounds:
movs(r_dprime, sint.get_edabit(k + kappa - m, True)[0])
tmp, b[:] = sint.get_edabit(m, True)
movs(r_prime, tmp)
return
t = [[program.curr_block.new_reg('s') for j in range(2)] for i in range(m)]
t[0][1] = b[-1]
PRandInt(r_dprime, k + kappa - m)
# r_dprime is always multiplied by 2^m
if use_dabit and program.use_dabit and m > 1 and not const_rounds:
r, b[:] = zip(*(sint.get_dabit() for i in range(m)))
r = sint.bit_compose(r)
movs(r_prime, r)
return
bit(b[-1])
for i in range(1, m):
adds(t[i][0], t[i - 1][1], t[i - 1][1])
bit(b[-i - 1])
adds(t[i][1], t[i][0], b[-i - 1])
movs(r_prime, t[m - 1][1])
def MaskingBitsInRing(m, strict=False):
from Compiler.types import sint
if program.use_edabit():
return sint.get_edabit(m, strict)
elif program.use_dabit:
r, r_bin = zip(*(sint.get_dabit() for i in range(m)))
else:
r = [sint.get_random_bit() for i in range(m)]
r_bin = r
return sint.bit_compose(r), r_bin
def Mod2mRing(a_prime, a, k, m, signed):
assert (int(program.options.ring) >= k)
from Compiler.types import sint, intbitint, cint
shift = int(program.options.ring) - m
if program.use_dabit:
r, r_bin = zip(*(sint.get_dabit() for i in range(m)))
else:
r = [sint.get_random_bit() for i in range(m)]
r_bin = r
r_prime = sint.bit_compose(r)
tmp = a + r_prime
c_prime = (tmp << shift).reveal() >> shift
u = sint()
BitLTL(u, c_prime, r_bin, 0)
res = (u << m) + c_prime - r_prime
if a_prime is not None:
movs(a_prime, res)
return res
