PyBitmessage/src/highlevelcrypto.py
bmng-dev 9b40838f25 Use pointMult instead of arithmetic.privtopub
pointMult is faster than the pure python arithmetic.privtopub

Additionally in makeCryptor the call to a.privtopub could have just simply be changed to call the local privToPub but then privkey would have been dehexified twice (once in makeCryptor, then again in privToPub) and privToPub would have hexified its result only for makeCryptor to immediately dehexify it. This sort of unnecessary hexifying/dehexifying seems to occur throughout PyBitmessage.
2014-05-21 11:08:15 +00:00

57 lines
2.2 KiB
Python

import pyelliptic
from pyelliptic import arithmetic as a, OpenSSL
def makeCryptor(privkey):
private_key = a.changebase(privkey, 16, 256, minlen=32)
public_key = pointMult(private_key)
privkey_bin = '\x02\xca\x00\x20' + private_key
pubkey_bin = '\x02\xca\x00\x20' + public_key[1:-32] + '\x00\x20' + pubkey[-32:]
cryptor = pyelliptic.ECC(curve='secp256k1',privkey=privkey_bin,pubkey=pubkey_bin)
return cryptor
def hexToPubkey(pubkey):
pubkey_raw = a.changebase(pubkey[2:],16,256,minlen=64)
pubkey_bin = '\x02\xca\x00 '+pubkey_raw[:32]+'\x00 '+pubkey_raw[32:]
return pubkey_bin
def makePubCryptor(pubkey):
pubkey_bin = hexToPubkey(pubkey)
return pyelliptic.ECC(curve='secp256k1',pubkey=pubkey_bin)
# Converts hex private key into hex public key
def privToPub(privkey):
private_key = a.changebase(privkey, 16, 256, minlen=32)
public_key = pointMult(private_key)
return public_key.encode('hex')
# Encrypts message with hex public key
def encrypt(msg,hexPubkey):
return pyelliptic.ECC(curve='secp256k1').encrypt(msg,hexToPubkey(hexPubkey))
# Decrypts message with hex private key
def decrypt(msg,hexPrivkey):
return makeCryptor(hexPrivkey).decrypt(msg)
# Decrypts message with an existing pyelliptic.ECC.ECC object
def decryptFast(msg,cryptor):
return cryptor.decrypt(msg)
# Signs with hex private key
def sign(msg,hexPrivkey):
return makeCryptor(hexPrivkey).sign(msg)
# Verifies with hex public key
def verify(msg,sig,hexPubkey):
return makePubCryptor(hexPubkey).verify(sig,msg)
# Does an EC point multiplication; turns a private key into a public key.
def pointMult(secret):
k = OpenSSL.EC_KEY_new_by_curve_name(OpenSSL.get_curve('secp256k1'))
priv_key = OpenSSL.BN_bin2bn(secret, 32, None)
group = OpenSSL.EC_KEY_get0_group(k)
pub_key = OpenSSL.EC_POINT_new(group)
OpenSSL.EC_POINT_mul(group, pub_key, priv_key, None, None, None)
OpenSSL.EC_KEY_set_private_key(k, priv_key)
OpenSSL.EC_KEY_set_public_key(k, pub_key)
size = OpenSSL.i2o_ECPublicKey(k, None)
mb = OpenSSL.create_string_buffer(size)
OpenSSL.i2o_ECPublicKey(k, OpenSSL.byref(OpenSSL.pointer(mb)))
OpenSSL.EC_POINT_free(pub_key)
OpenSSL.BN_free(priv_key)
OpenSSL.EC_KEY_free(k)
return mb.raw