"""
M2Crypto wrapper for OpenSSL ECDH/ECDSA API.
@requires: OpenSSL 0.9.8 or newer
Copyright (c) 1999-2003 Ng Pheng Siong. All rights reserved.
Portions copyright (c) 2005-2006 Vrije Universiteit Amsterdam.
All rights reserved."""
import util, BIO, m2
class ECError(Exception): pass
m2.ec_init(ECError)
# Curve identifier constants
NID_secp112r1 = m2.NID_secp112r1
NID_secp112r2 = m2.NID_secp112r2
NID_secp128r1 = m2.NID_secp128r1
NID_secp128r2 = m2.NID_secp128r2
NID_secp160k1 = m2.NID_secp160k1
NID_secp160r1 = m2.NID_secp160r1
NID_secp160r2 = m2.NID_secp160r2
NID_secp192k1 = m2.NID_secp192k1
NID_secp224k1 = m2.NID_secp224k1
NID_secp224r1 = m2.NID_secp224r1
NID_secp256k1 = m2.NID_secp256k1
NID_secp384r1 = m2.NID_secp384r1
NID_secp521r1 = m2.NID_secp521r1
NID_sect113r1 = m2.NID_sect113r1
NID_sect113r2 = m2.NID_sect113r2
NID_sect131r1 = m2.NID_sect131r1
NID_sect131r2 = m2.NID_sect131r2
NID_sect163k1 = m2.NID_sect163k1
NID_sect163r1 = m2.NID_sect163r1
NID_sect163r2 = m2.NID_sect163r2
NID_sect193r1 = m2.NID_sect193r1
NID_sect193r2 = m2.NID_sect193r2
NID_sect233k1 = m2.NID_sect233k1 # default for secg.org TLS test server
NID_sect233r1 = m2.NID_sect233r1
NID_sect239k1 = m2.NID_sect239k1
NID_sect283k1 = m2.NID_sect283k1
NID_sect283r1 = m2.NID_sect283r1
NID_sect409k1 = m2.NID_sect409k1
NID_sect409r1 = m2.NID_sect409r1
NID_sect571k1 = m2.NID_sect571k1
NID_sect571r1 = m2.NID_sect571r1
NID_X9_62_prime192v1 = m2.NID_X9_62_prime192v1
NID_X9_62_prime192v2 = m2.NID_X9_62_prime192v2
NID_X9_62_prime192v3 = m2.NID_X9_62_prime192v3
NID_X9_62_prime239v1 = m2.NID_X9_62_prime239v1
NID_X9_62_prime239v2 = m2.NID_X9_62_prime239v2
NID_X9_62_prime239v3 = m2.NID_X9_62_prime239v3
NID_X9_62_prime256v1 = m2.NID_X9_62_prime256v1
NID_X9_62_c2pnb163v1 = m2.NID_X9_62_c2pnb163v1
NID_X9_62_c2pnb163v2 = m2.NID_X9_62_c2pnb163v2
NID_X9_62_c2pnb163v3 = m2.NID_X9_62_c2pnb163v3
NID_X9_62_c2pnb176v1 = m2.NID_X9_62_c2pnb176v1
NID_X9_62_c2tnb191v1 = m2.NID_X9_62_c2tnb191v1
NID_X9_62_c2tnb191v2 = m2.NID_X9_62_c2tnb191v2
NID_X9_62_c2tnb191v3 = m2.NID_X9_62_c2tnb191v3
NID_X9_62_c2pnb208w1 = m2.NID_X9_62_c2pnb208w1
NID_X9_62_c2tnb239v1 = m2.NID_X9_62_c2tnb239v1
NID_X9_62_c2tnb239v2 = m2.NID_X9_62_c2tnb239v2
NID_X9_62_c2tnb239v3 = m2.NID_X9_62_c2tnb239v3
NID_X9_62_c2pnb272w1 = m2.NID_X9_62_c2pnb272w1
NID_X9_62_c2pnb304w1 = m2.NID_X9_62_c2pnb304w1
NID_X9_62_c2tnb359v1 = m2.NID_X9_62_c2tnb359v1
NID_X9_62_c2pnb368w1 = m2.NID_X9_62_c2pnb368w1
NID_X9_62_c2tnb431r1 = m2.NID_X9_62_c2tnb431r1
NID_wap_wsg_idm_ecid_wtls1 = m2.NID_wap_wsg_idm_ecid_wtls1
NID_wap_wsg_idm_ecid_wtls3 = m2.NID_wap_wsg_idm_ecid_wtls3
NID_wap_wsg_idm_ecid_wtls4 = m2.NID_wap_wsg_idm_ecid_wtls4
NID_wap_wsg_idm_ecid_wtls5 = m2.NID_wap_wsg_idm_ecid_wtls5
NID_wap_wsg_idm_ecid_wtls6 = m2.NID_wap_wsg_idm_ecid_wtls6
NID_wap_wsg_idm_ecid_wtls7 = m2.NID_wap_wsg_idm_ecid_wtls7
NID_wap_wsg_idm_ecid_wtls8 = m2.NID_wap_wsg_idm_ecid_wtls8
NID_wap_wsg_idm_ecid_wtls9 = m2.NID_wap_wsg_idm_ecid_wtls9
NID_wap_wsg_idm_ecid_wtls10 = m2.NID_wap_wsg_idm_ecid_wtls10
NID_wap_wsg_idm_ecid_wtls11 = m2.NID_wap_wsg_idm_ecid_wtls11
NID_wap_wsg_idm_ecid_wtls12 = m2.NID_wap_wsg_idm_ecid_wtls12
# The following two curves, according to OpenSSL, have a
# "Questionable extension field!" and are not supported by
# the OpenSSL inverse function. ECError: no inverse.
# As such they cannot be used for signing. They might,
# however, be usable for encryption but that has not
# been tested. Until thir usefulness can be established,
# they are not supported at this time.
# NID_ipsec3 = m2.NID_ipsec3
# NID_ipsec4 = m2.NID_ipsec4
class EC:
"""
Object interface to a EC key pair.
"""
m2_ec_key_free = m2.ec_key_free
def __init__(self, ec, _pyfree=0):
assert m2.ec_key_type_check(ec), "'ec' type error"
self.ec = ec
self._pyfree = _pyfree
def __del__(self):
if getattr(self, '_pyfree', 0):
self.m2_ec_key_free(self.ec)
def __len__(self):
assert m2.ec_key_type_check(self.ec), "'ec' type error"
return m2.ec_key_keylen(self.ec)
def gen_key(self):
"""
Generates the key pair from its parameters. Use::
keypair = EC.gen_params(curve)
keypair.gen_key()
to create an EC key pair.
"""
assert m2.ec_key_type_check(self.ec), "'ec' type error"
m2.ec_key_gen_key(self.ec)
def pub(self):
# Don't let python free
return EC_pub(self.ec, 0)
def sign_dsa(self, digest):
"""
Sign the given digest using ECDSA. Returns a tuple (r,s), the two
ECDSA signature parameters.
"""
assert self._check_key_type(), "'ec' type error"
return m2.ecdsa_sign(self.ec, digest)
def verify_dsa(self, digest, r, s):
"""
Verify the given digest using ECDSA. r and s are the ECDSA
signature parameters.
"""
assert self._check_key_type(), "'ec' type error"
return m2.ecdsa_verify(self.ec, digest, r, s)
def sign_dsa_asn1(self, digest):
assert self._check_key_type(), "'ec' type error"
return m2.ecdsa_sign_asn1(self.ec, digest)
def verify_dsa_asn1(self, digest, blob):
assert self._check_key_type(), "'ec' type error"
return m2.ecdsa_verify_asn1(self.ec, digest, blob)
def compute_dh_key(self,pub_key):
"""
Compute the ECDH shared key of this key pair and the given public
key object. They must both use the same curve. Returns the
shared key in binary as a buffer object. No Key Derivation Function is
applied.
"""
assert self.check_key(), 'key is not initialised'
return m2.ecdh_compute_key(self.ec, pub_key.ec)
def save_key_bio(self, bio, cipher='aes_128_cbc', callback=util.passphrase_callback):
"""
Save the key pair to an M2Crypto.BIO.BIO object in PEM format.
@type bio: M2Crypto.BIO.BIO
@param bio: M2Crypto.BIO.BIO object to save key to.
@type cipher: string
@param cipher: Symmetric cipher to protect the key. The default
cipher is 'aes_128_cbc'. If cipher is None, then the key is saved
in the clear.
@type callback: Python callable
@param callback: A Python callable object that is invoked
to acquire a passphrase with which to protect the key.
The default is util.passphrase_callback.
"""
if cipher is None:
return m2.ec_key_write_bio_no_cipher(self.ec, bio._ptr(), callback)
else:
ciph = getattr(m2, cipher, None)
if ciph is None:
raise ValueError('not such cipher %s' % cipher)
return m2.ec_key_write_bio(self.ec, bio._ptr(), ciph(), callback)
def save_key(self, file, cipher='aes_128_cbc', callback=util.passphrase_callback):
"""
Save the key pair to a file in PEM format.
@type file: string
@param file: Name of file to save key to.
@type cipher: string
@param cipher: Symmetric cipher to protect the key. The default
cipher is 'aes_128_cbc'. If cipher is None, then the key is saved
in the clear.
@type callback: Python callable
@param callback: A Python callable object that is invoked
to acquire a passphrase with which to protect the key.
The default is util.passphrase_callback.
"""
bio = BIO.openfile(file, 'wb')
return self.save_key_bio(bio, cipher, callback)
def save_pub_key_bio(self, bio):
"""
Save the public key to an M2Crypto.BIO.BIO object in PEM format.
@type bio: M2Crypto.BIO.BIO
@param bio: M2Crypto.BIO.BIO object to save key to.
"""
return m2.ec_key_write_pubkey(self.ec, bio._ptr())
def save_pub_key(self, file):
"""
Save the public key to a file in PEM format.
@type file: string
@param file: Name of file to save key to.
"""
bio = BIO.openfile(file, 'wb')
return m2.ec_key_write_pubkey(self.ec, bio._ptr())
def _check_key_type(self):
return m2.ec_key_type_check(self.ec)
def check_key(self):
assert m2.ec_key_type_check(self.ec), "'ec' type error"
return m2.ec_key_check_key(self.ec)
class EC_pub(EC):
"""
Object interface to an EC public key.
((don't like this implementation inheritance))
"""
def __init__(self,ec,_pyfree=0):
EC.__init__(self,ec,_pyfree)
self.der = None
def get_der(self):
"""
Returns the public key in DER format as a buffer object.
"""
assert self.check_key(), 'key is not initialised'
if self.der is None:
self.der = m2.ec_key_get_public_der(self.ec)
return self.der
save_key = EC.save_pub_key
save_key_bio = EC.save_pub_key_bio
def gen_params(curve):
"""
Factory function that generates EC parameters and
instantiates a EC object from the output.
@param curve: This is the OpenSSL nid of the curve to use.
"""
return EC(m2.ec_key_new_by_curve_name(curve), 1)
def load_key(file, callback=util.passphrase_callback):
"""
Factory function that instantiates a EC object.
@param file: Names the file that contains the PEM representation
of the EC key pair.
@param callback: Python callback object that will be invoked
if the EC key pair is passphrase-protected.
"""
bio = BIO.openfile(file)
return load_key_bio(bio, callback)
def load_key_bio(bio, callback=util.passphrase_callback):
"""
Factory function that instantiates a EC object.
@param bio: M2Crypto.BIO object that contains the PEM
representation of the EC key pair.
@param callback: Python callback object that will be invoked
if the EC key pair is passphrase-protected.
"""
return EC(m2.ec_key_read_bio(bio._ptr(), callback), 1)
def load_pub_key(file):
"""
Load an EC public key from file.
@type file: string
@param file: Name of file containing EC public key in PEM format.
@rtype: M2Crypto.EC.EC_pub
@return: M2Crypto.EC.EC_pub object.
"""
bio = BIO.openfile(file)
return load_pub_key_bio(bio)
def load_pub_key_bio(bio):
"""
Load an EC public key from an M2Crypto.BIO.BIO object.
@type bio: M2Crypto.BIO.BIO
@param bio: M2Crypto.BIO.BIO object containing EC public key in PEM
format.
@rtype: M2Crypto.EC.EC_pub
@return: M2Crypto.EC.EC_pub object.
"""
ec = m2.ec_key_read_pubkey(bio._ptr())
if ec is None:
ec_error()
return EC_pub(ec, 1)
def ec_error():
raise ECError, m2.err_reason_error_string(m2.err_get_error())
def pub_key_from_der(der):
"""
Create EC_pub from DER.
"""
return EC_pub(m2.ec_key_from_pubkey_der(der), 1)