PSI_De_Christofaro/psi_de_christofaro_srv.py at master · kpatsakis/PSI_De_Christofaro · GitHub

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#!/usr/bin/python
###SERVER###
import random
from time import time
import gmpy
import hashlib
from flask import Flask
from flask import request

e=2**16+1
app = Flask(__name__)

def hash_int(x):
    return int(hashlib.sha256(str(x)).hexdigest(),16)

#generates a random prime of the requested bit length
def gen_prime(BIT_LEN):
    found=False
    while found==False:
        p=random.randrange(2**(BIT_LEN-1),2**BIT_LEN)
        found=gmpy.is_prime(p)
    return p

#generates a random safe prime of the requested bit length
def gen_safe_prime(BIT_LEN):
    found=False
    while found==False:
        q=random.randrange(2**(BIT_LEN-2),2**(BIT_LEN-1))
        p=2*q+1
        found=gmpy.is_prime(p) and gmpy.is_prime(q)
    return p


def RSA_GEN(BIT_LEN):
    # this is faster but not so secure
    p=gen_prime(BIT_LEN)
    q=gen_prime(BIT_LEN)

    # p=gen_safe_prime(BIT_LEN)
    # q=gen_safe_prime(BIT_LEN)

    n=p*q
    f=(p-1)*(q-1)
    e=2**16+1
    d=gmpy.invert(e,f)
    return d,n

def RSA_ENC(m,n):
    return pow(m,e,n)
def RSA_DEC(c,d,n):
    return pow(c,d,n)

@app.route('/', methods=['GET', 'POST'])
def hello_world():
    if request.method == 'POST':
        vals = request.form['params']
        print "Client values received"

        client_elements=vals.split(",")
        for i in range(len(client_elements)):
            client_elements[i]=int(client_elements[i])

        m_B1=[RSA_DEC(x,d,n) for x in client_elements]
        hs=[hash_int(i) for i in server_elements]
        m_B2=[hash_int(RSA_DEC(y,d,n)) for y in hs]
        print "sending response..."

        client_enc=""
        for cc in m_B1:
            client_enc+=str(cc)+","
        client_enc=client_enc[:-1]
        srv_enc=""
        for cc in m_B2:
            srv_enc+=str(cc)+","
        srv_enc=srv_enc[:-1]
        resp= client_enc+"|"+srv_enc
        return str(resp)

if __name__ == '__main__':
    #generate RSA key pair (public,private) for the server
    d,n=RSA_GEN(512)

    fout=open("srv.key","w")
    fout.write(str(n))
    fout.close()

    fin=open("srv_elements.txt","r")
    srv_vals=fin.read()
    fin.close()
    server_elements=srv_vals.split(",")
    for i in range(len(server_elements)):
        server_elements[i]=int(server_elements[i])

    app.run()