def raw_get_ecdh_key(self, pubkey_x, pubkey_y):
"""ECDH key as binary data"""
try:
ecdh_keybuffer = OpenSSL.malloc(0, 32)
other_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if other_key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
other_pub_key_x = OpenSSL.BN_bin2bn(pubkey_x, len(pubkey_x), 0)
other_pub_key_y = OpenSSL.BN_bin2bn(pubkey_y, len(pubkey_y), 0)
other_group = OpenSSL.EC_KEY_get0_group(other_key)
other_pub_key = OpenSSL.EC_POINT_new(other_group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(
other_group, other_pub_key, other_pub_key_x,
other_pub_key_y, 0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(other_key, other_pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(other_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
own_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if own_key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
own_priv_key = OpenSSL.BN_bin2bn(self.privkey, len(self.privkey),
0)
if (OpenSSL.EC_KEY_set_private_key(own_key, own_priv_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_private_key FAIL ...")
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EC_KEY_set_method(own_key, OpenSSL.EC_KEY_OpenSSL())
else:
OpenSSL.ECDH_set_method(own_key, OpenSSL.ECDH_OpenSSL())
ecdh_keylen = OpenSSL.ECDH_compute_key(ecdh_keybuffer, 32,
other_pub_key, own_key, 0)
if ecdh_keylen != 32:
raise Exception("[OpenSSL] ECDH keylen FAIL ...")
return ecdh_keybuffer.raw
finally:
OpenSSL.EC_KEY_free(other_key)
OpenSSL.BN_free(other_pub_key_x)
OpenSSL.BN_free(other_pub_key_y)
OpenSSL.EC_POINT_free(other_pub_key)
OpenSSL.EC_KEY_free(own_key)
OpenSSL.BN_free(own_priv_key)
