from __future__ import absolute_import
"""M2Crypto wrapper for OpenSSL DH API.
Copyright (c) 1999-2003 Ng Pheng Siong. All rights reserved."""
from M2Crypto import BIO, m2
from M2Crypto.util import genparam_callback
from typing import AnyStr, Callable, Optional # noqa
[docs]
class DHError(Exception):
pass
m2.dh_init(DHError)
[docs]
class DH(object):
"""Object interface to the Diffie-Hellman key exchange protocol.
"""
m2_dh_free = m2.dh_free
def __init__(self, dh, _pyfree=0):
# type: (bytes, int) -> None
assert m2.dh_type_check(dh)
self.dh = dh
self._pyfree = _pyfree
def __del__(self):
# type: () -> None
if getattr(self, '_pyfree', 0):
self.m2_dh_free(self.dh)
def __len__(self):
# type: () -> int
assert m2.dh_type_check(self.dh), "'dh' type error"
return int(m2.dh_size(self.dh))
def __getattr__(self, name):
# type: (str) -> bytes
if name in ('p', 'g', 'pub', 'priv'):
method = getattr(m2, 'dh_get_%s' % (name,))
assert m2.dh_type_check(self.dh), "'dh' type error"
return method(self.dh)
else:
raise AttributeError
def __setattr__(self, name, value):
# type: (str, bytes) -> bytes
if name in ('p', 'g'):
raise DHError('set (p, g) via set_params()')
elif name in ('pub', 'priv'):
raise DHError('generate (pub, priv) via gen_key()')
else:
self.__dict__[name] = value
def _ptr(self):
return self.dh
[docs]
def check_params(self):
# type: () -> int
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_check(self.dh)
[docs]
def gen_key(self):
# type: () -> None
assert m2.dh_type_check(self.dh), "'dh' type error"
m2.dh_generate_key(self.dh)
[docs]
def compute_key(self, pubkey):
# type: (bytes) -> bytes
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_compute_key(self.dh, pubkey)
[docs]
def print_params(self, bio):
# type: (BIO.BIO) -> int
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dhparams_print(bio._ptr(), self.dh)
[docs]
def gen_params(plen, g, callback=genparam_callback):
# type: (int, int, Optional[Callable]) -> DH
dh_parms = m2.dh_generate_parameters(plen, g, callback)
dh_obj = DH(dh_parms, 1)
return dh_obj
[docs]
def load_params(file):
# type: (AnyStr) -> DH
with BIO.openfile(file) as bio:
return load_params_bio(bio)
[docs]
def load_params_bio(bio):
# type: (BIO.BIO) -> DH
return DH(m2.dh_read_parameters(bio._ptr()), 1)
[docs]
def set_params(p, g):
# type: (bytes, bytes) -> DH
dh = m2.dh_new()
m2.dh_set_pg(dh, p, g)
return DH(dh, 1)
# def free_params(cptr):
# m2.dh_free(cptr)
DH_GENERATOR_2 = m2.DH_GENERATOR_2
DH_GENERATOR_5 = m2.DH_GENERATOR_5