"""M2Crypto wrapper for OpenSSL DH API.
Copyright (c) 1999-2003 Ng Pheng Siong. All rights reserved."""
from util import genparam_callback
import BIO, Err, m2
class DHError(Exception): pass
m2.dh_init(DHError)
class DH:
"""
Object interface to the Diffie-Hellman key exchange
protocol.
"""
m2_dh_free = m2.dh_free
def __init__(self, dh, _pyfree=0):
assert m2.dh_type_check(dh)
self.dh = dh
self._pyfree = _pyfree
def __del__(self):
if getattr(self, '_pyfree', 0):
self.m2_dh_free(self.dh)
def __len__(self):
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_size(self.dh)
def __getattr__(self, name):
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):
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
def check_params(self):
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_check(self.dh)
def gen_key(self):
assert m2.dh_type_check(self.dh), "'dh' type error"
m2.dh_generate_key(self.dh)
def compute_key(self, pubkey):
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dh_compute_key(self.dh, pubkey)
def print_params(self, bio):
assert m2.dh_type_check(self.dh), "'dh' type error"
return m2.dhparams_print(bio._ptr(), self.dh)
def gen_params(plen, g, callback=genparam_callback):
return DH(m2.dh_generate_parameters(plen, g, callback), 1)
def load_params(file):
bio = BIO.openfile(file)
return load_params_bio(bio)
def load_params_bio(bio):
return DH(m2.dh_read_parameters(bio._ptr()), 1)
def set_params(p, g):
dh = m2.dh_new()
m2.dh_set_p(dh, p)
m2.dh_set_g(dh, 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