ZeroNet/plugins/CryptMessage/CryptMessage.py

53 lines
1.8 KiB
Python

from lib.pybitcointools import bitcoin as btctools
import hashlib
ecc_cache = {}
def encrypt(data, pubkey, ephemcurve=None, ciphername='aes-256-cbc'):
from lib import pyelliptic
curve, pubkey_x, pubkey_y, i = pyelliptic.ECC._decode_pubkey(pubkey)
if ephemcurve is None:
ephemcurve = curve
ephem = pyelliptic.ECC(curve=ephemcurve)
key = hashlib.sha512(ephem.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()
key_e, key_m = key[:32], key[32:]
pubkey = ephem.get_pubkey()
iv = pyelliptic.OpenSSL.rand(pyelliptic.OpenSSL.get_cipher(ciphername).get_blocksize())
ctx = pyelliptic.Cipher(key_e, iv, 1, ciphername)
ciphertext = iv + pubkey + ctx.ciphering(data)
mac = pyelliptic.hmac_sha256(key_m, ciphertext)
return key_e, ciphertext + mac
def split(encrypted):
iv = encrypted[0:16]
ciphertext = encrypted[16+70:-32]
return iv, ciphertext
def getEcc(privatekey=None):
from lib import pyelliptic
global eccs
if privatekey not in ecc_cache:
if privatekey:
publickey_bin = btctools.encode_pubkey(btctools.privtopub(privatekey), "bin")
publickey_openssl = toOpensslPublickey(publickey_bin)
privatekey_openssl = toOpensslPrivatekey(privatekey)
ecc_cache[privatekey] = pyelliptic.ECC(curve='secp256k1', privkey=privatekey_openssl, pubkey=publickey_openssl)
else:
ecc_cache[None] = pyelliptic.ECC()
return ecc_cache[privatekey]
def toOpensslPrivatekey(privatekey):
privatekey_bin = btctools.encode_privkey(privatekey, "bin")
return '\x02\xca\x00\x20' + privatekey_bin
def toOpensslPublickey(publickey):
publickey_bin = btctools.encode_pubkey(publickey, "bin")
publickey_bin = publickey_bin[1:]
publickey_openssl = '\x02\xca\x00 ' + publickey_bin[:32] + '\x00 ' + publickey_bin[32:]
return publickey_openssl