forked from upstream/UXP-mirror
Jeremy Andrews
0c61ee391c
reduce is moved to functools, urllib reogranized. 2to3 . --fix urllib -wpn 2to3 . --fix reduce -wpn 2to3 . --fix import -wpn 2to3 . --fix imports -wpn 2to3 . --fix imports2 -wpn Ref: PEP 3108, PEP 3100 https://peps.python.org/pep-3108/ https://peps.python.org/pep-3100/
66 lines
2.1 KiB
Python
66 lines
2.1 KiB
Python
# Elliptic Curve Hybrid Encryption Scheme
|
|
#
|
|
# COPYRIGHT (c) 2010 by Toni Mattis <solaris@live.de>
|
|
#
|
|
|
|
from .curves import get_curve
|
|
from .elliptic import mulp
|
|
from .encoding import enc_long
|
|
from random import SystemRandom
|
|
from .Rabbit import Rabbit
|
|
|
|
# important for cryptographically secure random numbers:
|
|
random = SystemRandom()
|
|
|
|
# Encryption Algorithm:
|
|
# ---------------------
|
|
# Input: Message M, public key Q
|
|
#
|
|
# 0. retrieve the group from which Q was generated.
|
|
# 1. generate random number k between 1 and the group order.
|
|
# 2. compute KG = k * G (where G is the base point of the group).
|
|
# 3. compute SG = k * Q (where Q is the public key of the receiver).
|
|
# 4. symmetrically encrypt M to M' using SG's x-coordinate as key.
|
|
#
|
|
# Return: Ciphertext M', temporary key KG
|
|
|
|
|
|
def encrypt(message, qk, encrypter = Rabbit):
|
|
'''Encrypt a message using public key qk => (ciphertext, temp. pubkey)'''
|
|
bits, q = qk
|
|
try:
|
|
bits, cn, n, cp, cq, g = get_curve(bits)
|
|
if not n:
|
|
raise ValueError("Key size %s not suitable for encryption" % bits)
|
|
except KeyError:
|
|
raise ValueError("Key size %s not implemented" % bits)
|
|
|
|
k = random.randint(1, n - 1) # temporary private key k
|
|
kg = mulp(cp, cq, cn, g, k) # temporary public key k*G
|
|
sg = mulp(cp, cq, cn, q, k) # shared secret k*Q = k*d*G
|
|
|
|
return encrypter(enc_long(sg[0])).encrypt(message), kg
|
|
|
|
# Decryption Algorithm:
|
|
# ---------------------
|
|
# Input: Ciphertext M', temporary key KG, private key d
|
|
#
|
|
# 0. retrieve the group from which d and KG were generated.
|
|
# 1. compute SG = q * KG.
|
|
# 2. symmetrically decrypt M' to M using SG's x-coordinate as key.
|
|
#
|
|
# Return: M
|
|
|
|
def decrypt(message, kg, dk, decrypter = Rabbit):
|
|
'''Decrypt a message using temp. public key kg and private key dk'''
|
|
bits, d = dk
|
|
try:
|
|
bits, cn, n, cp, cq, g = get_curve(bits)
|
|
except KeyError:
|
|
raise ValueError("Key size %s not implemented" % bits)
|
|
|
|
sg = mulp(cp, cq, cn, kg, d) # shared secret d*(k*G) = k*d*G
|
|
return decrypter(enc_long(sg[0])).decrypt(message)
|
|
|
|
|