def test_decode_dss_invalid_asn1():
with pytest.raises(ValueError):
# This byte sequence has an invalid ASN.1 sequence length as well as
# an invalid integer length for the second integer.
decode_dss_signature(b"0\x07\x02\x01\x01\x02\x02\x01")
with pytest.raises(ValueError):
# This is the BER "end-of-contents octets".
decode_dss_signature(b"\x00\x00")
def test_decode_dss_invalid_asn1():
with pytest.raises(ValueError):
# This byte sequence has an invalid ASN.1 sequence length as well as
# an invalid integer length for the second integer.
decode_dss_signature(b"0\x07\x02\x01\x01\x02\x02\x01")
with pytest.raises(ValueError):
# This is the BER "end-of-contents octets".
decode_dss_signature(b"\x00\x00")
def test_decode_dss_invalid_asn1():
with pytest.raises(ValueError):
# This byte sequence has an invalid ASN.1 sequence length as well as
# an invalid integer length for the second integer.
decode_dss_signature(b"0\x07\x02\x01\x01\x02\x02\x01")
with pytest.raises(ValueError):
# This is the BER "end-of-contents octets," which older versions of
# pyasn1 are wrongly willing to return from top-level DER decoding.
decode_dss_signature(b"\x00\x00")
def test_decode_dss_invalid_asn1():
with pytest.raises(ValueError):
# This byte sequence has an invalid ASN.1 sequence length as well as
# an invalid integer length for the second integer.
decode_dss_signature(b"0\x07\x02\x01\x01\x02\x02\x01")
with pytest.raises(ValueError):
# This is the BER "end-of-contents octets," which older versions of
# pyasn1 are wrongly willing to return from top-level DER decoding.
decode_dss_signature(b"\x00\x00")
def der_to_raw_signature(der_sig, curve):
num_bits = curve.key_size
num_bytes = (num_bits + 7) // 8
r, s = decode_dss_signature(der_sig)
return number_to_bytes(r, num_bytes) + number_to_bytes(s, num_bytes)
def der_to_raw_signature(der_sig: bytes, curve: EllipticCurve) -> bytes:
num_bits = curve.key_size
num_bytes = (num_bits + 7) // 8
r, s = decode_dss_signature(der_sig)
return number_to_bytes(r, num_bytes) + number_to_bytes(s, num_bytes)
def test_cryptography_module():
try:
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import dsa
from cryptography.hazmat.primitives.asymmetric.utils import decode_dss_signature
privk = dsa.generate_private_key(key_size=1024,
backend=default_backend())
params = privk.parameters().parameter_numbers()
p, q, g = params.p, params.q, params.g
pubk = privk.public_key()
y = pubk.public_numbers().y
data = "SANITY_TESTSANITY_TEST_SANITYTEST"
sig = privk.sign(data, hashes.SHA1())
r, s = decode_dss_signature(sig)
pub = (p, q, g, y)
logging.debug(
"sanity checking verify with cryptography module generated params+keys"
)
assert (dsa_verify(pub, (r, s), data) == True)
except ImportError:
logging.error("cannot test using another source (cryptography module)")
def sign(self, data):
"""
Sign some data with this key.
SECSH-TRANS RFC 4253 Section 6.6.
@type data: L{bytes}
@param data: The data to sign.
@rtype: L{bytes}
@return: A signature for the given data.
"""
if self.type() == 'RSA':
signer = self._keyObject.signer(
padding.PKCS1v15(), hashes.SHA1())
signer.update(data)
ret = common.NS(signer.finalize())
elif self.type() == 'DSA':
signer = self._keyObject.signer(hashes.SHA1())
signer.update(data)
signature = signer.finalize()
(r, s) = decode_dss_signature(signature)
# SSH insists that the DSS signature blob be two 160-bit integers
# concatenated together. The sig[0], [1] numbers from obj.sign
# are just numbers, and could be any length from 0 to 160 bits.
# Make sure they are padded out to 160 bits (20 bytes each)
ret = common.NS(int_to_bytes(r, 20) + int_to_bytes(s, 20))
else:
raise BadKeyError("unknown key type %s" % (self.type(),))
return common.NS(self.sshType()) + ret
def _ecc_static_length_signature(key, algorithm, digest):
"""Calculates an elliptic curve signature with a static length using pre-calculated hash.
:param key: Elliptic curve private key
:type key: cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey
:param algorithm: Master algorithm to use
:type algorithm: aws_encryption_sdk.identifiers.Algorithm
:param bytes digest: Pre-calculated hash digest
:returns: Signature with required length
:rtype: bytes
"""
pre_hashed_algorithm = ec.ECDSA(Prehashed(algorithm.signing_hash_type()))
signature = b''
while len(signature) != algorithm.signature_len:
_LOGGER.debug(
'Signature length %d is not desired length %d. Recalculating.',
len(signature), algorithm.signature_len)
signature = key.sign(digest, pre_hashed_algorithm)
if len(signature) != algorithm.signature_len:
# Most of the time, a signature of the wrong length can be fixed
# by negating s in the signature relative to the group order.
_LOGGER.debug(
'Signature length %d is not desired length %d. Negating s.',
len(signature), algorithm.signature_len)
r, s = decode_dss_signature(signature)
s = _ECC_CURVE_PARAMETERS[
algorithm.signing_algorithm_info.name].order - s
signature = encode_dss_signature(r, s)
return signature
def get_hnp_approximation():
global nsigs, count_true, count
ud = os.urandom(8)
res, ud, sig = sidechannel_cache(userdata=ud)
nsigs += 1
m_b = compute_m_from_userdata(ud)
m = int(m_b.encode("hex"), 16)
r, s = decode_dss_signature(sig)
q = order
m = m % q
flag = sidechannel_info.give_range(m, r, q)
if res == 0:
t, u, v = compute_approximation_from_sig(m, r, s, q, res)
no_msb = math.log(q / v) / math.log(2)
if no_msb > b:
# print_flag(flag)
# print_flag(res)
# count+=1
# count_true+=int(flag==res)
# print count,count_true,flag==res
print flag == res
return t, u, v
else:
return None
else:
return None
def _ecdsa_sha256_response(self, challenge):
"""Compute the ecdsa signature
Args:
challenge: content of challenge in bytes
Returns:
r_bytes, s_bytes: ecdsa signature R, S in bytes
Raises:
BootstrapError: if the gateway cannot be properly loaded
"""
try:
challenge_key = cert_utils.load_key(self._challenge_key_file)
except (IOError, ValueError, TypeError) as e:
raise BootstrapError(
'Gateway does not have a proper challenge key: %s' % e)
try:
signature = challenge_key.sign(challenge,
ec.ECDSA(hashes.SHA256()))
except TypeError:
raise BootstrapError(
'Challenge key cannot be used for ECDSA signature')
r_int, s_int = decode_dss_signature(signature)
r_bytes = r_int.to_bytes((r_int.bit_length() + 7) // 8, 'big')
s_bytes = s_int.to_bytes((s_int.bit_length() + 7) // 8, 'big')
return r_bytes, s_bytes
def sign(self, data):
"""
It will generate the signature for data on local private key
"""
return decode_dss_signature(
self.private_key.sign(
json.dumps(data).encode('utf-8'), ec.ECDSA(hashes.SHA256())))
def __msg2_sign(self, msg2, blob):
priv_sig_key_bytes = bytes().fromhex(
AttestationContext.common_ec_private_key_hex)
priv_sig_key_int = int.from_bytes(priv_sig_key_bytes,
byteorder='little',
signed=False)
common_ec_key = ec.derive_private_key(priv_sig_key_int, P_256,
OPENSSL_BACKEND)
sig_material = bytearray()
sig_material += self.gb_x
sig_material += self.gb_y
sig_material += self.ga_x
sig_material += self.ga_y
# generate signature
signature_der = common_ec_key.sign(bytes(sig_material),
ec.ECDSA(SHA256()))
r, s = decode_dss_signature(signature_der)
sig_x = r.to_bytes(32, byteorder='little')
sig_y = s.to_bytes(32, byteorder='little')
# append to the binary blob to me CMACed
blob += sig_x
blob += sig_y
# append to msg2
sig_sp = {}
sig_sp['x_coord'] = base64.b64encode(sig_x).decode('utf-8')
sig_sp['y_coord'] = base64.b64encode(sig_y).decode('utf-8')
msg2['sig_sp'] = sig_sp
def sign(self, data):
"""
Sign some data with this key.
SECSH-TRANS RFC 4253 Section 6.6.
@type data: L{bytes}
@param data: The data to sign.
@rtype: L{bytes}
@return: A signature for the given data.
"""
if self.type() == 'RSA':
signer = self._keyObject.signer(padding.PKCS1v15(), hashes.SHA1())
signer.update(data)
ret = common.NS(signer.finalize())
elif self.type() == 'DSA':
signer = self._keyObject.signer(hashes.SHA1())
signer.update(data)
signature = signer.finalize()
(r, s) = decode_dss_signature(signature)
# SSH insists that the DSS signature blob be two 160-bit integers
# concatenated together. The sig[0], [1] numbers from obj.sign
# are just numbers, and could be any length from 0 to 160 bits.
# Make sure they are padded out to 160 bits (20 bytes each)
ret = common.NS(int_to_bytes(r, 20) + int_to_bytes(s, 20))
else:
raise BadKeyError("unknown key type %s" % (self.type(), ))
return common.NS(self.sshType()) + ret
def sign(self, data):
'''
generate a signature
'''
return decode_dss_signature(
self.private_key.sign(
json.dumps(data).encode('utf-8'), ec.ECDSA(hashes.SHA256())))
def build_oca():
""" Builds a self-signed OCA certificate using ECSDA with SHA256 and curve
NIST-P384. Returns a tuple of the private key and the signed certificate"""
private_key = ec.generate_private_key(
ec.SECP384R1, default_backend()
)
public_nr = private_key.public_key().public_numbers()
oca = bytearray(0x824)
oca[0x0:0x4] = (1).to_bytes(4,'little')
oca[0x4] = 0x00 # API Major
oca[0x5] = 0x00 # API Minor
oca[0x6:0x8] = b'\x00\x00'
oca[0x8:0xc] = (0x1001).to_bytes(4,'little') # Usage: OCA
oca[0xc:0x10] = (2).to_bytes(4,'little') # ECDSA-SHA256
# Begin pubkey
oca[0x10:0x14] = (2).to_bytes(4,'little') # Curve ID: NIST-P384
oca[0x14:0x14+0x48] = (public_nr.x).to_bytes(0x48,'little')
oca[0x5c:0x5c+0x48] = (public_nr.y).to_bytes(0x48,'little')
# Begin signature
oca[0x414:0x418] = (0x1001).to_bytes(4,'little') # 1st signature usage: OCA
oca[0x418:0x41c] = (2).to_bytes(4,'little') # ECDSA-SHA256
sig = utils.decode_dss_signature(ecdsa_sign(private_key,oca[:0x414]))
oca[0x41c:0x41c+0x48] = (sig[0]).to_bytes(0x48,'little') # R
oca[0x464:0x464+0x48] = (sig[1]).to_bytes(0x48,'little') # S
oca[0x61c:0x620] = (0x1000).to_bytes(4,'little') # 2nd signature usage: Invalid
return (private_key, oca)
def build_pdh(pek):
""" Builds the platform-diffie-hellman key (PDH) and signs it with the
provided platform-endorsement-key (PEK).
Returns a tuple of the signed PDH and the corresponding private key. """
private_key = ec.generate_private_key(
ec.SECP384R1, default_backend()
)
public_nr = private_key.public_key().public_numbers()
pdh = bytearray(0x824)
pdh[0x0:0x4] = (1).to_bytes(4,'little')
pdh[0x4] = 0x0 # API Major
pdh[0x5] = 0x00 # API Minor
pdh[0x6:0x8] = b'\x00\x00'
pdh[0x8:0xc] = (0x1003).to_bytes(4,'little') # Usage: PDH
pdh[0xc:0x10] = (3).to_bytes(4,'little') # ECDH-SHA256
# Begin pubkey
pdh[0x10:0x14] = (2).to_bytes(4,'little') # Curve ID: NIST-P384
pdh[0x14:0x14+0x48] = (public_nr.x).to_bytes(0x48,'little')
pdh[0x5c:0x5c+0x48] = (public_nr.y).to_bytes(0x48,'little')
# Begin 1st signature
pdh[0x414:0x418] = (0x1002).to_bytes(4,'little') # 1st signature usage: PEK
pdh[0x418:0x41c] = (2).to_bytes(4,'little') # ECDSA-SHA256
sig = utils.decode_dss_signature(ecdsa_sign(pek,pdh[:0x414])) # Sign with OCA
pdh[0x41c:0x41c+0x48] = (sig[0]).to_bytes(0x48,'little') # R
pdh[0x464:0x464+0x48] = (sig[1]).to_bytes(0x48,'little') # S
# Begin 2nd signature
pdh[0x61c:0x620] = (0x1000).to_bytes(4,'little') # 2nd signature usage: Invalid
return (private_key, pdh)
def sign_ssh_data(self, data):
key = dsa.DSAPrivateNumbers(
x=self.x,
public_numbers=dsa.DSAPublicNumbers(
y=self.y,
parameter_numbers=dsa.DSAParameterNumbers(
p=self.p,
q=self.q,
g=self.g
)
)
).private_key(backend=default_backend())
signer = key.signer(hashes.SHA1())
signer.update(data)
r, s = decode_dss_signature(signer.finalize())
m = Message()
m.add_string('ssh-dss')
# apparently, in rare cases, r or s may be shorter than 20 bytes!
rstr = util.deflate_long(r, 0)
sstr = util.deflate_long(s, 0)
if len(rstr) < 20:
rstr = zero_byte * (20 - len(rstr)) + rstr
if len(sstr) < 20:
sstr = zero_byte * (20 - len(sstr)) + sstr
m.add_string(rstr + sstr)
return m
def sign(self, message):
message = _helpers.to_bytes(message)
asn1_signature = self._key.sign(message, ec.ECDSA(hashes.SHA256()))
# Convert ASN1 encoded signature to (r||s) raw signature.
(r, s) = decode_dss_signature(asn1_signature)
return utils.int_to_bytes(r, 32) + utils.int_to_bytes(s, 32)
def get_cose_es_bytes(options, private_key, sig_val):
ASN1_signature = private_key.sign(sig_val, ec.ECDSA(hashes.SHA256()))
r, s = asymmetric_utils.decode_dss_signature(ASN1_signature)
ssize = private_key.key_size
signature_bytes = r.to_bytes(ssize // 8, byteorder='big') + s.to_bytes(
ssize // 8, byteorder='big')
return signature_bytes
def createPrivateSignature(context):
data = bytes(context, encoding='utf8')
# Read the pri_key_file
digest = hashes.Hash(hashes.SHA256(), default_backend())
digest.update(data)
dgst = digest.finalize()
skey = load_pem_private_key(PRIVATE_KEY,
password=None,
backend=default_backend())
sig_data = skey.sign(data, ec.ECDSA(hashes.SHA256()))
sig_r, sig_s = decode_dss_signature(sig_data)
sig_bytes = b''
key_size_in_bytes = bit_to_bytes(skey.public_key().key_size)
sig_r_bytes = sig_r.to_bytes(key_size_in_bytes, "big")
sig_bytes += sig_r_bytes
#print("ECDSA signature R: {:s}".format(sig_r_bytes.hex()))
sig_s_bytes = sig_s.to_bytes(key_size_in_bytes, "big")
sig_bytes += sig_s_bytes
# print("ECDSA signature S: {:s}".format(sig_s_bytes.hex()))
# print("ECDSA signautre: {:s}".format(sig_bytes.hex()))
#print("ECDSA signautre: " + str(base64.b64encode(sig_bytes)))
return base64.b64encode(sig_bytes)
def create_key_signature(private_key: bytes,
challenger_public_key: bytes,
enclave_public_key: bytes):
logging.info("Creating key signature")
assert len(challenger_public_key) == 64
assert len(enclave_public_key) == 64
# Reverse public key byte order
g_b = challenger_public_key[:32][::-1] + challenger_public_key[32:][::-1]
g_a = enclave_public_key[:32][::-1] + enclave_public_key[32:][::-1]
gb_ga = g_b + g_a
logging.debug("gb_ga: %r | %r\n", g_b.hex(), g_a.hex())
private_value = int.from_bytes(private_key, byteorder='big')
ec_private_key = ec.derive_private_key(private_value, EC_CURVE, default_backend())
der_signature = ec_private_key.sign(gb_ga, ec.ECDSA(hashes.SHA256()))
r, s = utils.decode_dss_signature(der_signature)
signature = r.to_bytes(32, byteorder='big') + s.to_bytes(32, byteorder='big')
logging.debug("challenger_public_key (g_b): %r | %r\n", challenger_public_key[:32].hex(), challenger_public_key[32:].hex())
logging.debug("enclave_public_key (g_a): %r | %r\n", enclave_public_key[:32].hex(), enclave_public_key[32:].hex())
logging.debug("signature: %r | %r\n", signature[:32].hex(), signature[32:].hex())
assert len(signature) == 64
return signature
def sign(self, header, payload):
"""Computes the signed jws as defined at rfc7515#section-7.1.
Args:
header: bytes, the header to be signed.
payload: bytes, the payload to be signed.
Returns:
base64url(header) || '.' || base64url(payload) || '.' ||
base64url(signature), where the signature is computed over
base64url(utf8(header)) || '.' || base64url(payload).
"""
if not isinstance(header, six.binary_type) or not isinstance(
payload, six.binary_type):
raise TypeError("header and payload must be bytes.")
signing_input = jwsutil.urlsafe_b64encode(
header) + b"." + jwsutil.urlsafe_b64encode(payload)
signature = self.signer.sign(signing_input)
if self.algorithm[:2] == "ES":
# Standard Ecdsa signature is the DER encoding of [r, s] while Jws's
# singature is the concatenation of r and s.
(r, s) = utils.decode_dss_signature(signature)
curve_length = jwsutil.ecdsa_algorithm_to_curve_length(
self.algorithm)
signature = jwsutil.int_to_bytes(
r, curve_length) + jwsutil.int_to_bytes(s, curve_length)
return signing_input + b"." + jwsutil.urlsafe_b64encode(signature)
def signature(self, msg):
"""
Create a signature for a message in a backwards compatible fashion
:param msg: the message to sign
"""
# Create the pyca signature
signer = self.ec.signer(ec.ECDSA(hashes.SHA1()))
signer.update(msg)
signature = signer.finalize()
# Decode the DSS r and s variables from the pyca signature
# We are going to turn these longs into (binary) string format
r, s = decode_dss_signature(signature)
# Convert the r and s to a valid hex representation
r = hex(r).rstrip("L").lstrip("0x") or "0"
s = hex(s).rstrip("L").lstrip("0x") or "0"
# We want bytes: one byte is two nibbles:
# Prefix with a 0 if the result is of odd length
if len(r) % 2 == 1:
r = "0" + r
if len(s) % 2 == 1:
s = "0" + s
# Now we can turn this into a binary string
r = unhexlify(r)
s = unhexlify(s)
key_len = self.get_signature_length() / 2
# For easy decoding, prepend 0 to r and s until they are of >equal length<
return "".join(
("\x00" * (key_len - len(r)), r, "\x00" * (key_len - len(s)), s))
def sign(self, data):
"""
Generate a signature based on the data using the local private key.
"""
return decode_dss_signature(
self.private_key.sign(
json.dumps(data).encode('utf-8'), ec.ECDSA(hashes.SHA256())))
def sign(self, key: ec.EllipticCurvePrivateKey, msg: bytes) -> bytes:
"""Sign the ``msg`` using ``key``."""
sig = self._sign(key, msg)
dr, ds = decode_dss_signature(sig)
length = jwk.JWKEC.expected_length_for_curve(key.curve)
return (dr.to_bytes(length=length, byteorder='big') +
ds.to_bytes(length=length, byteorder='big'))
def sign_prehashed(self, hash):
sig_der = self.key.sign(hash, ec.ECDSA(utils.Prehashed(SHA256())))
signature = utils.decode_dss_signature(sig_der)
signature_bin = signature[0].to_bytes(32, 'big')
signature_bin += signature[1].to_bytes(32, 'big')
return signature_bin
def ecc_sign(self,
private_key: Union[ec.EllipticCurvePrivateKey, bytes],
data: bytes,
algorithm: str = None) -> bytes:
"""Sign data using (EC)DSA.
:param private_key: ECC private key
:param data: Data to sign
:param algorithm: Hash algorithm, if None the hash length is determined from ECC curve size
:return: Signature, r and s coordinates as bytes
"""
if isinstance(private_key, bytes):
private_key = serialization.load_pem_private_key(
private_key, None, default_backend())
assert isinstance(private_key, ec.EllipticCurvePrivateKey)
hash_name = algorithm or f'sha{private_key.key_size}'
der_signature = private_key.sign(data,
signature_algorithm=ec.ECDSA(
self._get_algorithm(hash_name)))
# pylint: disable=invalid-name # we want to use established names
r, s = utils.decode_dss_signature(der_signature)
coordinate_size = math.ceil(private_key.key_size / 8)
r_bytes = r.to_bytes(coordinate_size, byteorder='big')
s_bytes = s.to_bytes(coordinate_size, byteorder='big')
return r_bytes + s_bytes
def sign_ssh_data(self, data):
key = dsa.DSAPrivateNumbers(
x=self.x,
public_numbers=dsa.DSAPublicNumbers(
y=self.y,
parameter_numbers=dsa.DSAParameterNumbers(
p=self.p,
q=self.q,
g=self.g
)
)
).private_key(backend=default_backend())
signer = key.signer(hashes.SHA1())
signer.update(data)
r, s = decode_dss_signature(signer.finalize())
m = Message()
m.add_string('ssh-dss')
# apparently, in rare cases, r or s may be shorter than 20 bytes!
rstr = util.deflate_long(r, 0)
sstr = util.deflate_long(s, 0)
if len(rstr) < 20:
rstr = zero_byte * (20 - len(rstr)) + rstr
if len(sstr) < 20:
sstr = zero_byte * (20 - len(sstr)) + sstr
m.add_string(rstr + sstr)
return m
def sign(self, header, payload):
"""Computes the signed jws as defined at rfc7515#section-7.1.
Args:
header: dict, dictionary of header to convert to JSON and sign.
payload: dict, dictionary of the payload to conert to JSON and sign.
Returns:
bytes, the signed token as defined at
https://tools.ietf.org/html/rfc7515#section-7.1.
Raises:
SecurityException: if the header's algorithm or kid does not match the
key's.
"""
if ((header.get("alg", None) is not None
and header["alg"] != self.algorithm)
or (header.get("kid", None) is not None
and getattr(self, "kid", None) is not None
and header["kid"] != self.kid)):
raise SecurityException(
"Header's algorithm or kid does not match the key's")
signing_input = jwsutil.urlsafe_b64encode(
jwsutil.json_encode(header)) + b"." + jwsutil.urlsafe_b64encode(
jwsutil.json_encode(payload))
signature = self.signer.sign(signing_input)
if self.algorithm[:2] == "ES":
# Standard Ecdsa signature is the DER encoding of [r, s] while Jws's
# singature is the concatenation of r and s.
(r, s) = utils.decode_dss_signature(signature)
curve_length = jwsutil.ecdsa_algorithm_to_curve_length(
self.algorithm)
signature = jwsutil.int_to_bytes(
r, curve_length) + jwsutil.int_to_bytes(s, curve_length)
return signing_input + b"." + jwsutil.urlsafe_b64encode(signature)
def test_dss_signature():
sig = encode_dss_signature(1, 1)
assert sig == b"0\x06\x02\x01\x01\x02\x01\x01"
assert decode_dss_signature(sig) == (1, 1)
r_s1 = (1037234182290683143945502320610861668562885151617,
559776156650501990899426031439030258256861634312)
sig2 = encode_dss_signature(*r_s1)
assert sig2 == (
b'0-\x02\x15\x00\xb5\xaf0xg\xfb\x8bT9\x00\x13\xccg\x02\r\xdf\x1f,\x0b'
b'\x81\x02\x14b\r;"\xabP1D\x0c>5\xea\xb6\xf4\x81)\x8f\x9e\x9f\x08')
assert decode_dss_signature(sig2) == r_s1
sig3 = encode_dss_signature(0, 0)
assert sig3 == b"0\x06\x02\x01\x00\x02\x01\x00"
assert decode_dss_signature(sig3) == (0, 0)
def convert_ecdsa_signature_from_der_to_p1363(
signature_der: bytes, key_size_bits: int
) -> bytes:
(r, s) = decode_dss_signature(signature_der)
assert key_size_bits % 8 == 0
n = key_size_bits // 8
signature_p1363 = r.to_bytes(n, byteorder="big") + s.to_bytes(n, byteorder="big")
return signature_p1363
def sign(self, message):
message = _helpers.to_bytes(message)
asn1_signature = self._key.sign(message, ec.ECDSA(hashes.SHA256()))
# Convert ASN1 encoded signature to (r||s) raw signature.
(r, s) = decode_dss_signature(asn1_signature)
return r.to_bytes(32, byteorder="big") + s.to_bytes(32,
byteorder="big")
def sign(self, data):
'''
Generate a signature based on the data using the local private key.
'''
return decode_dss_signature(self.private_key.sign(
json.dumps(data).encode('utf-8'),
ec.ECDSA(hashes.SHA256())
))#DSA here is digital signature algorithm
def sign_ssh_data(self, data):
ecdsa = ec.ECDSA(self.ecdsa_curve.hash_object())
sig = self.signing_key.sign(data, ecdsa)
r, s = decode_dss_signature(sig)
m = Message()
m.add_string(self.ecdsa_curve.key_format_identifier)
m.add_string(self._sigencode(r, s))
return m
def sign(self, data, hash_context):
if not isinstance(hash_context, hashes.HashContext):
raise TypeError("hash_context must be an instance of hashes.HashContext.")
signer = self._key.signer(hashes.SHA256())
signer._hash_ctx = hash_context
signer.update(data)
r, s = decode_dss_signature(signer.finalize())
# return long_to_bytes(r, 20) + long_to_bytes(s, 20)
size = self.private_numbers.public_numbers.parameter_numbers.q.bit_length() // 8
return long_to_bytes(r, size) + long_to_bytes(s, size)
def test_dss_signature():
sig = encode_dss_signature(1, 1)
assert sig == b"0\x06\x02\x01\x01\x02\x01\x01"
assert decode_dss_signature(sig) == (1, 1)
r_s1 = (1037234182290683143945502320610861668562885151617, 559776156650501990899426031439030258256861634312)
sig2 = encode_dss_signature(*r_s1)
assert sig2 == (
b"0-\x02\x15\x00\xb5\xaf0xg\xfb\x8bT9\x00\x13\xccg\x02\r\xdf\x1f,\x0b"
b'\x81\x02\x14b\r;"\xabP1D\x0c>5\xea\xb6\xf4\x81)\x8f\x9e\x9f\x08'
)
assert decode_dss_signature(sig2) == r_s1
sig3 = encode_dss_signature(0, 0)
assert sig3 == b"0\x06\x02\x01\x00\x02\x01\x00"
assert decode_dss_signature(sig3) == (0, 0)
sig4 = encode_dss_signature(-1, 0)
assert sig4 == b"0\x06\x02\x01\xFF\x02\x01\x00"
assert decode_dss_signature(sig4) == (-1, 0)
def sign(self, payload):
"""
Sign a payload
:param payload: String (usually jwt payload)
:return: URL safe base64 signature
"""
signer = self._private_key.signer(ec.ECDSA(hashes.SHA256()))
signer.update(payload)
signature = signer.finalize()
r, s = decode_dss_signature(signature)
b64_signature = utils.base64url_encode('{r}{s}'.format(r=int2bytes(r),
s=int2bytes(s)))
return b64_signature
def sign(self, payload):
"""
Sign a payload
:param payload: String (usually jwt payload)
:return: URL safe base64 signature
"""
signer = self._private_key.signer(ec.ECDSA(hashes.SHA256()))
signer.update(utils.to_bytes(payload))
signature = signer.finalize()
r, s = decode_dss_signature(signature)
br = int2bytes(r, KEYSIZE_BYTES)
bs = int2bytes(s, KEYSIZE_BYTES)
str_sig = br + bs
b64_signature = utils.base64url_encode(str_sig)
return b64_signature
def sign(claims, key):
"""Sign the claims
:param claims: list of JWS claims
:type claims: dict
:param key: Private key for signing
:type key: ec.EllipticCurvePrivateKey
:param algorithm: JWT "alg" descriptor
:type algorithm: str
"""
header = b64urlencode(b"""{"typ":"JWT","alg":"ES256"}""")
# Unfortunately, chrome seems to require the claims to be sorted.
claims = b64urlencode(json.dumps(claims,
separators=(',', ':'),
sort_keys=True).encode('utf8'))
token = "{}.{}".format(header, claims)
rsig = key.sign(token.encode('utf8'), ec.ECDSA(hashes.SHA256()))
(r, s) = utils.decode_dss_signature(rsig)
sig = b64urlencode(num_to_bytes(r) + num_to_bytes(s))
return "{}.{}".format(token, sig)
def der_decode(signature_bin):
"""
This decodes a DER encoded signature so that it can be used with ecdsa.
It uses the decode_dss_signature() function from cryptography.
:param signature_bin: DER encoded signature
:type signature_bin: bytes
:return: raw signature
:rtype: bytes
"""
try:
r, s = decode_dss_signature(signature_bin)
sig_bin_asn = binascii.unhexlify('{0:064x}{1:064x}'.format(r, s))
except ValueError as _e:
raise Exception("The signature is not in supported DER format.")
# we can only check for too long signatures since we prepend the hex-values
# with '0' to reach 64 digits. This will prevent an error in case the one of
# the values (r, s) is smaller than 32 bytes (first byte is '0'
# in original value).
if len(sig_bin_asn) != 64:
raise Exception("The signature needs to be 64 bytes.")
return sig_bin_asn
def _der_to_raw(self, der_signature):
"""Convert signature from DER encoding to RAW encoding."""
r, s = decode_dss_signature(der_signature)
component_length = self._sig_component_length()
return int_to_bytes(r, component_length) + int_to_bytes(s, component_length)
def test_decode_dss_trailing_bytes():
with pytest.raises(ValueError):
decode_dss_signature(b"0\x06\x02\x01\x01\x02\x01\x01\x00\x00\x00")
