Commit be96115ddce9cf7c1cd97f3309effaeeee259fe5

FEATURES: added get_random_prime() to pypbc; adding example cryptosytem
KSW.py
(80 / 0)
  
1#! /usr/bin/env python3
2
3"""
4KSW.py
5
6Written by Geremy Condra
7Licensed under GPLv3
8Released 15 October 2009
9
10An implementation of the Katz-Sahai-Waters predicate
11encryption scheme in Python3.
12"""
13
14from pypbc import *
15
16#############################################
17# Utilities #
18#############################################
19
20def dot_product(x, y, n):
21 """Takes the dot product of lists x and y over F_n"""
22
23 if len(x) != len(y):
24 raise ValueError("x and y must be the same length!")
25 if not isinstance(n, int):
26 raise ValueError("n must be an integer!")
27
28 return sum([(x_i * y[i]) % n for i, x_i in enumerate(x)])
29
30#############################################
31# Cryptosystem #
32#############################################
33
34class Cryptosystem:
35
36 params = None
37 pairing = None
38 # generates G
39 g_G = None
40 # generates G_p
41 g_G_p = None
42 # generates G_q
43 g_G_q = None
44 # generates G_r
45 g_G_r = None
46 # random element of G_r
47 R0 = None
48 # Rs[] = ((Ri,0), (Ri, 1)) * n, R e G_r
49 Rs = None
50 # Hs[] = ((Hi,0), (Hi, 1)) * n, H e G_p
51 Hs = None
52
53 def __init__(self, i) -> "(PK, SK)":
54 # select p, q, r
55 # make n
56 # build the params
57 # build the pairing
58 # find the generators for the G_p, G_q, and G_r subgroups
59 # choose R0
60 # choose the random R's
61 # choose the random H's
62 # calculate Q
63 pass
64
65 def keygen(sk: "master secret key", f: "description of a predicate") -> "SK_f":
66 pass
67
68 def encrypt(pk: "public key", i: "attribute", m: "message") -> "ciphertext":
69 pass
70
71 def decrypt(c: "ciphertext", sk_f: "secret key corresponding to predicate f") -> "message or T":
72 pass
73
74#############################################
75# Test logic #
76#############################################
77
78if __name__ == "__main__":
79
80 import sys
pypbc.c
(40 / 1)
  
2020 mpz_init_set_str(new_n, n_char, 10);
2121}
2222
23PyObject *get_random_prime(PyObject *self, PyObject *args) {
24 // gets the number of bits from the args
25 int num_bits;
26 if (!PyArg_ParseTuple(args, "i", &num_bits)) {
27 PyErr_SetString(PyExc_TypeError, "could not parse arguments");
28 return NULL;
29 }
30
31 // create the storage number
32 mpz_t c, p;
33 mpz_init(c);
34 mpz_init(p);
2335
36 // get a random n-bit number
37 pbc_mpz_randomb(c, num_bits);
38
39 // get the next prime
40 mpz_nextprime(p, c);
41
42 // get the mpz as a string
43 char *str_prime = mpz_get_str(NULL, 10, p);
44
45 // convert the string to a python long
46 PyObject *rand_prime = PyLong_FromString(str_prime, NULL, 10);
47
48 // clean up the mpz's
49 mpz_clear(c);
50 mpz_clear(p);
51
52 // clean up the str
53 free(str_prime);
54 return rand_prime;
55}
56
57
2458/*******************************************************************************
2559* Params *
2660*******************************************************************************/
……
10261026* Module *
10271027*******************************************************************************/
10281028
1029PyMethodDef pypbc_methods[] = {
1030 {"get_random_prime", get_random_prime, METH_VARARGS, "get a random n-bit prime"},
1031 {NULL, NULL, 0, NULL}
1032};
1033
10291034PyModuleDef pypbc_module = {
10301035 PyModuleDef_HEAD_INIT,
10311036 "pypbc",
10321037 "pypbc",
10331038 -1,
1034 NULL, NULL, NULL, NULL, NULL
1039 pypbc_methods
10351040};
10361041
10371042PyMODINIT_FUNC