private set intersection

psi.py

'''
https://github.com/OpenMined/PyPSI
'''
import gmpy2
import secrets
import hashlib
from Crypto.PublicKey import RSA

class PSI(object):
    def __init__(self, rsa_size=1024):
        self.private_key = RSA.generate(rsa_size)

        self.public_key = RSA.construct((self.private_key.n, self.private_key.e))
        self.r = secrets.randbelow(self.public_key.n)

    def YA(self, x):
        return x * gmpy2.powmod(self.r, self.public_key.e, self.public_key.n) % self.public_key.n

    def ZA(self, ya):
        return gmpy2.powmod(ya, self.private_key.d, self.private_key.n)

    def DA(self, za):
        return za * gmpy2.invert(self.r, self.public_key.n) % self.public_key.n

    def hash(self, x):
        if isinstance(x, int):
            return x
        s = hashlib.sha1(x).hexdigest()
        return int(s, 16)

    def ZB(self, x):
        return gmpy2.powmod(x, self.private_key.d, self.private_key.n)


    def YA_set(self, x):
        return np.array(x) * gmpy2.powmod(self.r, self.public_key.e, self.public_key.n) % self.public_key.n

    def ZA_set(self, ya):
        o = []
        for x in ya:
            o.append(self.ZA(x))
        return o
    
    def DA_set(self, za):
        return np.array(za) * gmpy2.invert(self.r, self.public_key.n) % self.public_key.n

    def test(self, xa, xb):
        xa = self.hash(xa)
        da = self.DA(self.ZA(self.YA(xa)))
        xb = self.hash(xb)
        zb = self.ZB(xb)
        return da, zb , da==zb

https://fate.readthedocs.io/en/latest/federatedml/statistic/intersect/README.html#figure-1