"""M2Crypto wrapper for OpenSSL DH API.
Copyright (c) 1999-2003 Ng Pheng Siong. All rights reserved."""
from M2Crypto import BIO, m2, types as C
from M2Crypto.util import genparam_callback
from typing import Callable, Optional, Union # noqa
[docs]
class DHError(Exception):
pass
m2.dh_init(DHError)
[docs]
class DH(object):
"""Object interface to the Diffie-Hellman key exchange protocol."""
def __init__(self, dh: C.DH, _pyfree: int = 0) -> None:
assert m2.dh_type_check(dh)
self.dh = dh
self._pyfree = _pyfree
[docs]
@staticmethod
def m2_dh_free(dh: C.DH) -> None:
m2.dh_free(dh)
def __del__(self) -> None:
if getattr(self, "_pyfree", 0):
self.m2_dh_free(self.dh)
def __len__(self) -> int:
assert m2.dh_type_check(self.dh), "'dh' type error"
return int(m2.dh_size(self.dh))
def __getattr__(self, name: 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: str, value: bytes) -> None:
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) -> int:
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_check(self.dh)
[docs]
def gen_key(self) -> None:
assert m2.dh_type_check(self.dh), "'dh' type error"
m2.dh_generate_key(self.dh)
[docs]
def compute_key(self, pubkey: 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: 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: int,
g: int,
callback: Callable = genparam_callback,
) -> DH:
dh_parms = m2.dh_generate_parameters(plen, g, callback)
dh_obj = DH(dh_parms, 1)
return dh_obj
[docs]
def load_params(file: Union[str, bytes]) -> DH:
with BIO.openfile(file) as bio:
return load_params_bio(bio)
[docs]
def load_params_bio(bio: BIO.BIO) -> DH:
dh_ptr = m2.dh_read_parameters(bio._ptr())
if dh_ptr is None:
raise DHError("Failed to load DH parameters.")
return DH(dh_ptr, 1)
[docs]
def set_params(p: bytes, g: 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