def testDecode6(self):
# Two integers
der = DerSequence()
der.decode(b('0\x08\x02\x02\x01\x80\x02\x02\x00\xff'))
self.assertEquals(len(der),2)
self.assertEquals(der[0],0x180L)
self.assertEquals(der[1],0xFFL)
def testDecode4(self):
# One very long integer
der = DerSequence()
der.decode(b('0\x82\x01\x05')+
b('\x02\x82\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00'))
self.assertEquals(len(der),1)
self.assertEquals(der[0],2L**2048)
def testDecode7(self):
# One integer and 2 other types
der = DerSequence()
der.decode(b('0\x0A\x02\x02\x01\x80\x24\x02\xb6\x63\x12\x00'))
self.assertEquals(len(der),3)
self.assertEquals(der[0],0x180L)
self.assertEquals(der[1],b('\x24\x02\xb6\x63'))
self.assertEquals(der[2],b('\x12\x00'))
def _create_subject_public_key_info(algo_oid, secret_key, params=None):
if params is None:
params = DerNull()
spki = DerSequence([
DerSequence([
DerObjectId(algo_oid),
params]),
DerBitString(secret_key)
])
return spki.encode()
def verify(self, msg_hash, signature):
"""Verify that a certain DSS signature is authentic.
This function checks if the party holding the private half of the key
really signed the message.
:Parameters:
msg_hash : hash object
The hash that was carried out over the message.
This is an object belonging to the `Cryptodome.Hash` module.
Under mode *'fips-186-3'*, the hash must be a FIPS
approved secure hash (SHA-1 or a member of the SHA-2 family),
of cryptographic strength appropriate for the DSA key.
For instance, a 3072/256 DSA key can only be used in
combination with SHA-512.
signature : byte string
The signature that needs to be validated.
:Raise ValueError:
If the signature is not authentic.
"""
if not self._valid_hash(msg_hash):
raise ValueError("Hash does not belong to SHS")
if self._encoding == 'binary':
if len(signature) != (2 * self._order_bytes):
raise ValueError("The signature is not authentic (length)")
r_prime, s_prime = [Integer.from_bytes(x)
for x in (signature[:self._order_bytes],
signature[self._order_bytes:])]
else:
try:
der_seq = DerSequence().decode(signature)
except (ValueError, IndexError):
raise ValueError("The signature is not authentic (DER)")
if len(der_seq) != 2 or not der_seq.hasOnlyInts():
raise ValueError("The signature is not authentic (DER content)")
r_prime, s_prime = der_seq[0], der_seq[1]
if not (0 < r_prime < self._order) or not (0 < s_prime < self._order):
raise ValueError("The signature is not authentic (d)")
z = Integer.from_bytes(msg_hash.digest()[:self._order_bytes])
result = self._key._verify(z, (r_prime, s_prime))
if not result:
raise ValueError("The signature is not authentic")
# Make PyCryptodome code to fail
return False
def testEncode2(self):
# Indexing
der = DerSequence()
der.append(0)
der[0] = 1
self.assertEquals(len(der),1)
self.assertEquals(der[0],1)
self.assertEquals(der[-1],1)
self.assertEquals(der.encode(), b('0\x03\x02\x01\x01'))
#
der[:] = [1]
self.assertEquals(len(der),1)
self.assertEquals(der[0],1)
self.assertEquals(der.encode(), b('0\x03\x02\x01\x01'))
def der2rsa(der):
# Extract subjectPublicKeyInfo field from X.509 certificate (see RFC3280)
cert = DerSequence()
cert.decode(der)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0])
subject_public_key_info = tbs_certificate[6]
# Initialize RSA key
return RSA.importKey(subject_public_key_info)
def verify(self, msg_hash, signature):
"""Check if a certain (EC)DSA signature is authentic.
Args:
msg_hash (hash object):
The hash that was carried out over the message.
This is an object belonging to the :mod:`Cryptodome.Hash` module.
Under mode ``'fips-186-3'``, the hash must be a FIPS
approved secure hash (SHA-2 or SHA-3).
signature (``bytes``):
The signature that needs to be validated.
:raise ValueError: if the signature is not authentic
"""
if not self._valid_hash(msg_hash):
raise ValueError("Hash is not sufficiently strong")
if self._encoding == 'binary':
if len(signature) != (2 * self._order_bytes):
raise ValueError("The signature is not authentic (length)")
r_prime, s_prime = [
Integer.from_bytes(x) for x in (signature[:self._order_bytes],
signature[self._order_bytes:])
]
else:
try:
der_seq = DerSequence().decode(signature, strict=True)
except (ValueError, IndexError):
raise ValueError("The signature is not authentic (DER)")
if len(der_seq) != 2 or not der_seq.hasOnlyInts():
raise ValueError(
"The signature is not authentic (DER content)")
r_prime, s_prime = Integer(der_seq[0]), Integer(der_seq[1])
if not (0 < r_prime < self._order) or not (0 < s_prime < self._order):
raise ValueError("The signature is not authentic (d)")
z = Integer.from_bytes(msg_hash.digest()[:self._order_bytes])
result = self._key._verify(z, (r_prime, s_prime))
if not result:
raise ValueError("The signature is not authentic")
# Make PyCryptodome code to fail
return False
def testEncode8(self):
# One integer and another type (yet to encode)
der = DerSequence()
der.append(0x180L)
der.append(DerSequence([5]))
self.assertEquals(der.encode(), b('0\x09\x02\x02\x01\x800\x03\x02\x01\x05'))
self.failIf(der.hasOnlyInts())
def testEncode7(self):
# One integer and another type (already encoded)
der = DerSequence()
der.append(0x180)
der.append(b('0\x03\x02\x01\x05'))
self.assertEquals(der.encode(), b('0\x09\x02\x02\x01\x800\x03\x02\x01\x05'))
self.failIf(der.hasOnlyInts())
def import_key(extern_key, salt=None):
der, marker, _ = PEM.decode(extern_key)
ints = DerSequence().decode(der)
if not marker.startswith('myDSA'):
raise ValueError('Invalid format')
key_dict = dict(zip(('p', 'q', 'g', 'y', 'x'), map(Integer, ints)))
return myDSA(key_dict, salt)
def testDecode8(self):
# Only 2 other types
der = DerSequence()
der.decode(b('0\x06\x24\x02\xb6\x63\x12\x00'))
self.assertEquals(len(der), 2)
self.assertEquals(der[0], b('\x24\x02\xb6\x63'))
self.assertEquals(der[1], b('\x12\x00'))
self.assertEquals(der.hasInts(), 0)
self.assertEquals(der.hasInts(False), 0)
self.failIf(der.hasOnlyInts())
self.failIf(der.hasOnlyInts(False))
def testEncode8(self):
# One integer and another type (yet to encode)
der = DerSequence()
der.append(0x180L)
der.append(DerSequence([5]))
self.assertEquals(der.encode(),
b('0\x09\x02\x02\x01\x800\x03\x02\x01\x05'))
self.failIf(der.hasOnlyInts())
def _extract_subject_public_key_info(x509_certificate):
"""Extract subjectPublicKeyInfo from a DER X.509 certificate."""
certificate = DerSequence().decode(x509_certificate, nr_elements=3)
tbs_certificate = DerSequence().decode(certificate[0],
nr_elements=list(range(6, 11)))
index = 5
try:
tbs_certificate[0] + 1
# Version not present
version = 1
except TypeError:
version = DerInteger(explicit=0).decode(tbs_certificate[0]).value
if version not in (2, 3):
raise ValueError("Incorrect X.509 certificate version")
index = 6
return tbs_certificate[index]
def _import_pkcs8(encoded, passphrase, params):
if params:
raise ValueError("PKCS#8 already includes parameters")
k = PKCS8.unwrap(encoded, passphrase)
if k[0] != oid:
raise ValueError("No PKCS#8 encoded DSA key")
x = DerInteger().decode(k[1]).value
p, q, g = list(DerSequence().decode(k[2]))
tup = (pow(g, x, p), g, p, q, x)
return construct(tup)
def test_expected_only_integers(self):
der_bin1 = DerSequence([1, 2, 3]).encode()
der_bin2 = DerSequence([1, 2, DerSequence([3, 4])]).encode()
DerSequence().decode(der_bin1, only_ints_expected=True)
DerSequence().decode(der_bin1, only_ints_expected=False)
DerSequence().decode(der_bin2, only_ints_expected=False)
self.assertRaises(ValueError, DerSequence().decode, der_bin2, only_ints_expected=True)
def testErrDecode3(self):
# Wrong length format
der = DerSequence()
# Missing length in sub-item
self.assertRaises(ValueError, der.decode,
b('\x30\x04\x02\x01\x01\x00'))
# Valid BER, but invalid DER length
self.assertRaises(ValueError, der.decode,
b('\x30\x81\x03\x02\x01\x01'))
self.assertRaises(ValueError, der.decode,
b('\x30\x04\x02\x81\x01\x01'))
def testDecode1(self):
# Empty sequence
der = DerSequence()
der.decode(b('0\x00'))
self.assertEquals(len(der), 0)
# One single-byte integer (zero)
der.decode(b('0\x03\x02\x01\x00'))
self.assertEquals(len(der), 1)
self.assertEquals(der[0], 0)
# Invariant
der.decode(b('0\x03\x02\x01\x00'))
self.assertEquals(len(der), 1)
self.assertEquals(der[0], 0)
def generate_rsa_key_pair():
rsa_key = RSA.generate(2048)
private_key = DerSequence([0,
rsa_key.n,
rsa_key.e,
rsa_key.d,
rsa_key.p,
rsa_key.q,
rsa_key.d % (rsa_key.p - 1),
rsa_key.d % (rsa_key.q - 1),
Integer(rsa_key.q).inverse(rsa_key.p)
]).encode()
pub_key = rsa_key.publickey()
public_key = DerSequence([pub_key.n,
pub_key.e
]).encode()
return private_key, public_key
def _import_subjectPublicKeyInfo(encoded, passphrase, params):
algoid, encoded_key, emb_params = _expand_subject_public_key_info(encoded)
if algoid != oid:
raise ValueError("No DSA subjectPublicKeyInfo")
if params and emb_params:
raise ValueError("Too many DSA parameters")
y = DerInteger().decode(encoded_key).value
p, q, g = list(DerSequence().decode(params or emb_params))
tup = (y, g, p, q)
return construct(tup)
def rsa_public_from_der_certificate(certificate):
# Extract subject_public_key_info field from X.509 certificate (see RFC3280)
try:
# try to extract pubkey from scapy.layers.x509 X509Cert type in case
# der_certificate is of type X509Cert
# Note: der_certificate may not be of type X509Cert if it wasn't
# received completely, in that case, we'll try to extract it anyway
# using the old method.
# TODO: get rid of the old method and always expect X509Cert obj ?
return RSA.importKey(str(certificate.tbsCertificate.subjectPublicKeyInfo))
except AttributeError:
pass
# Fallback method, may pot. allow to extract pubkey from incomplete der streams
cert = DerSequence()
cert.decode(certificate)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0]) # first DER SEQUENCE
# search for pubkey OID: rsaEncryption: "1.2.840.113549.1.1.1"
# hex: 06 09 2A 86 48 86 F7 0D 01 01 01
subject_public_key_info = None
for seq in tbs_certificate:
if not isinstance(seq, basestring):
continue # skip numerics and non sequence stuff
if "\x2A\x86\x48\x86\xF7\x0D\x01\x01\x01" in seq:
subject_public_key_info = seq
if subject_public_key_info is None:
raise ValueError("could not find OID rsaEncryption 1.2.840.113549.1.1.1 in certificate")
# Initialize RSA key
return RSA.importKey(subject_public_key_info)
def test_verify(self):
# Ecdsa signature is not unique, so we only test if we can verify it
pri_key = ECC.generate(curve="P-256")
key = pri_key.export_key(format="DER")
pub_key = pri_key.public_key()
signer = Sha256WithEcdsaSigner("/K/KEY/x", key)
pkt = make_data("/test", MetaInfo(), b"test content", signer=signer)
_, _, _, sig_ptrs = parse_data(pkt)
# Test its format is ASN.1 der format
DerSequence().decode(bytes(sig_ptrs.signature_value_buf))
validator = EccChecker.from_key(
"/K/KEY/x", bytes(pub_key.export_key(format='DER')))
assert aio.run(validator(Name.from_str("/test"), sig_ptrs))
def rsa_public_from_der_certificate(certificate):
# Extract subject_public_key_info field from X.509 certificate (see RFC3280)
try:
# try to extract pubkey from scapy.layers.x509 X509Cert type in case
# der_certificate is of type X509Cert
# Note: der_certificate may not be of type X509Cert if it wasn't
# received completely, in that case, we'll try to extract it anyway
# using the old method.
# TODO: get rid of the old method and always expect X509Cert obj ?
"""
Rebuild ASN1 SubjectPublicKeyInfo since X509Cert does not provide the full struct
ASN1F_SEQUENCE(
ASN1F_SEQUENCE(ASN1F_OID("pubkey_algo","1.2.840.113549.1.1.1"),
ASN1F_field("pk_value",ASN1_NULL(0))),
ASN1F_BIT_STRING("pubkey","")
),
"""
subject_public_key_info = ASN1_SEQUENCE([
ASN1_SEQUENCE([certificate.pubkey_algo, certificate.pk_value]),
certificate.pubkey
])
return RSA.importKey(str(subject_public_key_info))
except AttributeError:
pass
# Fallback method, may pot. allow to extract pubkey from incomplete der streams
cert = DerSequence()
cert.decode(certificate)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0]) # first DER SEQUENCE
# search for pubkey OID: rsaEncryption: "1.2.840.113549.1.1.1"
# hex: 06 09 2A 86 48 86 F7 0D 01 01 01
subject_public_key_info = None
for seq in tbs_certificate:
if not isinstance(seq, basestring):
continue # skip numerics and non sequence stuff
if "\x2A\x86\x48\x86\xF7\x0D\x01\x01\x01" in seq:
subject_public_key_info = seq
if subject_public_key_info is None:
raise ValueError(
"could not find OID rsaEncryption 1.2.840.113549.1.1.1 in certificate"
)
# Initialize RSA key
return RSA.importKey(subject_public_key_info)
def testDecode8(self):
# Only 2 other types
der = DerSequence()
der.decode(b('0\x06\x24\x02\xb6\x63\x12\x00'))
self.assertEquals(len(der),2)
self.assertEquals(der[0],b('\x24\x02\xb6\x63'))
self.assertEquals(der[1],b('\x12\x00'))
self.assertEquals(der.hasInts(), 0)
self.assertEquals(der.hasInts(False), 0)
self.failIf(der.hasOnlyInts())
self.failIf(der.hasOnlyInts(False))
def get_public_key_from_file(file_name):
with open(file_name) as f:
pem = f.read()
lines = pem.replace(" ", '').split()
der = a2b_base64(''.join(lines[1:-1]))
# Extract subjectPublicKeyInfo field from X.509 certificate (see RFC3280)
cert = DerSequence()
cert.decode(der)
tbsCertificate = DerSequence()
tbsCertificate.decode(cert[0])
subjectPublicKeyInfo = tbsCertificate[6]
# Initialize RSA key
publicKey = RSA.importKey(subjectPublicKeyInfo)
return publicKey.publickey()
def _import_private_der(encoded, passphrase, curve_oid=None):
# See RFC5915 https://tools.ietf.org/html/rfc5915
#
# ECPrivateKey ::= SEQUENCE {
# version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
# privateKey OCTET STRING,
# parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
# publicKey [1] BIT STRING OPTIONAL
# }
private_key = DerSequence().decode(encoded, nr_elements=(3, 4))
if private_key[0] != 1:
raise ValueError("Incorrect ECC private key version")
try:
parameters = DerObjectId(explicit=0).decode(private_key[2]).value
if curve_oid is not None and parameters != curve_oid:
raise ValueError("Curve mismatch")
curve_oid = parameters
except ValueError:
pass
if curve_oid is None:
raise ValueError("No curve found")
for curve_name, curve in _curves.items():
if curve.oid == curve_oid:
break
else:
raise UnsupportedEccFeature("Unsupported ECC curve (OID: %s)" %
curve_oid)
scalar_bytes = DerOctetString().decode(private_key[1]).payload
modulus_bytes = curve.p.size_in_bytes()
if len(scalar_bytes) != modulus_bytes:
raise ValueError("Private key is too small")
d = Integer.from_bytes(scalar_bytes)
# Decode public key (if any)
if len(private_key) == 4:
public_key_enc = DerBitString(explicit=1).decode(private_key[3]).value
public_key = _import_public_der(public_key_enc, curve_oid=curve_oid)
point_x = public_key.pointQ.x
point_y = public_key.pointQ.y
else:
point_x = point_y = None
return construct(curve=curve_name, d=d, point_x=point_x, point_y=point_y)
def testDecode1(self):
# Empty sequence
der = DerSequence()
der.decode(b('0\x00'))
self.assertEquals(len(der),0)
# One single-byte integer (zero)
der.decode(b('0\x03\x02\x01\x00'))
self.assertEquals(len(der),1)
self.assertEquals(der[0],0)
# Invariant
der.decode(b('0\x03\x02\x01\x00'))
self.assertEquals(len(der),1)
self.assertEquals(der[0],0)
def export_key(self, keytype):
ints = [self.p, self.q, self.g, self.y]
if keytype == 'priv':
ints.append(self.x)
key_type = 'myDSA PRIVATE KEY'
elif keytype == 'pub':
key_type = 'myDSA PUBLIC KEY'
else:
raise ValueError('keytype should be one of "pub" or "priv"')
binary = DerSequence(ints).encode()
return PEM.encode(binary, key_type)
def _expand_subject_public_key_info(encoded):
"""Parse a SubjectPublicKeyInfo structure.
It returns a triple with:
* OID (string)
* encoded public key (bytes)
* Algorithm parameters (bytes or None)
"""
#
# SubjectPublicKeyInfo ::= SEQUENCE {
# algorithm AlgorithmIdentifier,
# subjectPublicKey BIT STRING
# }
#
# AlgorithmIdentifier ::= SEQUENCE {
# algorithm OBJECT IDENTIFIER,
# parameters ANY DEFINED BY algorithm OPTIONAL
# }
#
spki = DerSequence().decode(encoded, nr_elements=2)
algo = DerSequence().decode(spki[0], nr_elements=(1, 2))
algo_oid = DerObjectId().decode(algo[0])
spk = DerBitString().decode(spki[1]).value
if len(algo) == 1:
algo_params = None
else:
try:
DerNull().decode(algo[1])
algo_params = None
except:
algo_params = algo[1]
return algo_oid.value, spk, algo_params
def testEncode4(self):
# One very long integer
der = DerSequence()
der.append(2L**2048)
self.assertEquals(der.encode(), b('0\x82\x01\x05')+
b('\x02\x82\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00'))
def testEncode4(self):
# One very long integer
der = DerSequence()
der.append(2**2048)
self.assertEquals(der.encode(), b('0\x82\x01\x05')+
b('\x02\x82\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')+
b('\x00\x00\x00\x00\x00\x00\x00\x00\x00'))
def der2rsa(der):
# Extract subjectPublicKeyInfo field from X.509 certificate (see RFC3280)
cert = DerSequence()
cert.decode(der)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0])
subject_public_key_info = tbs_certificate[6]
# Initialize RSA key
return RSA.importKey(subject_public_key_info)
def test_verify(self):
# Ecdsa signature is not unique, so we only test if we can verify it
pri_key = ECC.generate(curve="P-256")
key = pri_key.export_key(format="DER")
pub_key = pri_key.public_key()
signer = Sha256WithEcdsaSigner("/K/KEY/x", key)
pkt = make_data("/test", MetaInfo(), b"test content", signer=signer)
_, _, _, sig_ptrs = parse_data(pkt)
# Test its format is ASN.1 der format
DerSequence().decode(bytes(sig_ptrs.signature_value_buf))
verifier = DSS.new(pub_key, 'fips-186-3', 'der')
h = SHA256.new()
for content in sig_ptrs.signature_covered_part:
h.update(content)
# verify() throws ValueError if it fails, the return value is undefined
# So do not assert its value
verifier.verify(h, bytes(sig_ptrs.signature_value_buf))
def sign(self, msg_hash):
"""Produce the DSA/ECDSA signature of a message.
:parameter msg_hash:
The hash that was carried out over the message.
The object belongs to the :mod:`Cryptodome.Hash` package.
Under mode *'fips-186-3'*, the hash must be a FIPS
approved secure hash (SHA-1 or a member of the SHA-2 family),
of cryptographic strength appropriate for the DSA key.
For instance, a 3072/256 DSA key can only be used
in combination with SHA-512.
:type msg_hash: hash object
:return: The signature as a *byte string*
:raise ValueError: if the hash algorithm is incompatible to the (EC)DSA key
:raise TypeError: if the (EC)DSA key has no private half
"""
if not self._valid_hash(msg_hash):
raise ValueError("Hash is not sufficiently strong")
# Generate the nonce k (critical!)
nonce = self._compute_nonce(msg_hash)
# Perform signature using the raw API
z = Integer.from_bytes(msg_hash.digest()[:self._order_bytes])
sig_pair = self._key._sign(z, nonce)
# Encode the signature into a single byte string
if self._encoding == 'binary':
output = b"".join([long_to_bytes(x, self._order_bytes)
for x in sig_pair])
else:
# Dss-sig ::= SEQUENCE {
# r INTEGER,
# s INTEGER
# }
# Ecdsa-Sig-Value ::= SEQUENCE {
# r INTEGER,
# s INTEGER
# }
output = DerSequence(sig_pair).encode()
return output
def _import_pkcs1_private(encoded, *kwargs):
# RSAPrivateKey ::= SEQUENCE {
# version Version,
# modulus INTEGER, -- n
# publicExponent INTEGER, -- e
# privateExponent INTEGER, -- d
# prime1 INTEGER, -- p
# prime2 INTEGER, -- q
# exponent1 INTEGER, -- d mod (p-1)
# exponent2 INTEGER, -- d mod (q-1)
# coefficient INTEGER -- (inverse of q) mod p
# }
#
# Version ::= INTEGER
der = DerSequence().decode(encoded, nr_elements=9, only_ints_expected=True)
if der[0] != 0:
raise ValueError("No PKCS#1 encoding of an RSA private key")
return construct(der[1:6] + [Integer(der[4]).inverse(der[5])])
def sign(self, msg_hash):
"""Compute the DSA/ECDSA signature of a message.
Args:
msg_hash (hash object):
The hash that was carried out over the message.
The object belongs to the :mod:`Cryptodome.Hash` package.
Under mode ``'fips-186-3'``, the hash must be a FIPS
approved secure hash (SHA-2 or SHA-3).
:return: The signature as ``bytes``
:raise ValueError: if the hash algorithm is incompatible to the (EC)DSA key
:raise TypeError: if the (EC)DSA key has no private half
"""
if not self._key.has_private():
raise TypeError("Private key is needed to sign")
if not self._valid_hash(msg_hash):
raise ValueError("Hash is not sufficiently strong")
# Generate the nonce k (critical!)
nonce = self._compute_nonce(msg_hash)
# Perform signature using the raw API
z = Integer.from_bytes(msg_hash.digest()[:self._order_bytes])
sig_pair = self._key._sign(z, nonce)
# Encode the signature into a single byte string
if self._encoding == 'binary':
output = b"".join(
[long_to_bytes(x, self._order_bytes) for x in sig_pair])
else:
# Dss-sig ::= SEQUENCE {
# r INTEGER,
# s INTEGER
# }
# Ecdsa-Sig-Value ::= SEQUENCE {
# r INTEGER,
# s INTEGER
# }
output = DerSequence(sig_pair).encode()
return output
def testEncode2(self):
# Indexing
der = DerSequence()
der.append(0)
der[0] = 1
self.assertEquals(len(der), 1)
self.assertEquals(der[0], 1)
self.assertEquals(der[-1], 1)
self.assertEquals(der.encode(), b('0\x03\x02\x01\x01'))
#
der[:] = [1]
self.assertEquals(len(der), 1)
self.assertEquals(der[0], 1)
self.assertEquals(der.encode(), b('0\x03\x02\x01\x01'))
def rsa_public_from_der_certificate(certificate):
# Extract subject_public_key_info field from X.509 certificate (see RFC3280)
try:
# try to extract pubkey from scapy.layers.x509 X509Cert type in case
# der_certificate is of type X509Cert
# Note: der_certificate may not be of type X509Cert if it wasn't
# received completely, in that case, we'll try to extract it anyway
# using the old method.
# TODO: get rid of the old method and always expect X509Cert obj ?
return RSA.importKey(
str(certificate.tbsCertificate.subjectPublicKeyInfo))
except AttributeError:
pass
# Fallback method, may pot. allow to extract pubkey from incomplete der streams
cert = DerSequence()
cert.decode(certificate)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0]) # first DER SEQUENCE
# search for pubkey OID: rsaEncryption: "1.2.840.113549.1.1.1"
# hex: 06 09 2A 86 48 86 F7 0D 01 01 01
subject_public_key_info = None
for seq in tbs_certificate:
if not isinstance(seq, bytes) and not isinstance(seq, str):
continue # skip numerics and non sequence stuff
if b"\x2A\x86\x48\x86\xF7\x0D\x01\x01\x01" in seq:
subject_public_key_info = seq
if subject_public_key_info is None:
raise ValueError(
"could not find OID rsaEncryption 1.2.840.113549.1.1.1 in certificate"
)
# Initialize RSA key
return RSA.importKey(subject_public_key_info)
def public_key_import_from_x509_certificate_string(certificate_string):
if certificate_string.find('-----BEGIN CERTIFICATE-----') \
and not certificate_string.find('-----BEGIN CERTIFICATE-----\n') \
and not certificate_string.find('-----BEGIN CERTIFICATE-----\r\n'):
certificate_string = certificate_string.replace(
'-----BEGIN CERTIFICATE-----', '-----BEGIN CERTIFICATE-----\n')
if certificate_string.find('\n-----END CERTIFICATE-----') \
and not certificate_string.find('\n-----END CERTIFICATE-----') \
and not certificate_string.find('\r\n-----END CERTIFICATE-----'):
certificate_string = certificate_string.replace(
'-----END CERTIFICATE-----', '\n-----END CERTIFICATE-----')
lines = certificate_string.replace(" ", '').split()
der = a2b_base64(''.join(lines[1:-1]))
# Extract subjectPublicKeyInfo field from X.509 certificate (see RFC3280)
cert = DerSequence()
cert.decode(der)
tbs_certificate = DerSequence()
tbs_certificate.decode(cert[0])
subject_public_key_info = tbs_certificate[6]
# Initialize RSA key
public_key = RSA.importKey(subject_public_key_info)
return public_key.publickey()
def _import_private_der(encoded, passphrase, curve_name=None):
# ECPrivateKey ::= SEQUENCE {
# version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
# privateKey OCTET STRING,
# parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
# publicKey [1] BIT STRING OPTIONAL
# }
private_key = DerSequence().decode(encoded, nr_elements=(3, 4))
if private_key[0] != 1:
raise ValueError("Incorrect ECC private key version")
try:
curve_name = DerObjectId(explicit=0).decode(private_key[2]).value
except ValueError:
pass
if curve_name != _curve.oid:
raise UnsupportedEccFeature("Unsupported ECC curve (OID: %s)" %
curve_name)
scalar_bytes = DerOctetString().decode(private_key[1]).payload
order_bytes = _curve.order.size_in_bytes()
if len(scalar_bytes) != order_bytes:
raise ValueError("Private key is too small")
d = Integer.from_bytes(scalar_bytes)
# Decode public key (if any, it must be P-256)
if len(private_key) == 4:
public_key_enc = DerBitString(explicit=1).decode(private_key[3]).value
public_key = _import_public_der(curve_name, public_key_enc)
point_x = public_key.pointQ.x
point_y = public_key.pointQ.y
else:
point_x = point_y = None
return construct(curve="P-256", d=d, point_x=point_x, point_y=point_y)
def testEncode5(self):
der = DerSequence()
der += 1
der += b('\x30\x00')
self.assertEquals(der.encode(), b('\x30\x05\x02\x01\x01\x30\x00'))
def testDecode2(self):
# One single-byte integer (non-zero)
der = DerSequence()
der.decode(b('0\x03\x02\x01\x7f'))
self.assertEquals(len(der),1)
self.assertEquals(der[0],127)
def export_key(self,
format='PEM',
passphrase=None,
pkcs=1,
protection=None,
randfunc=None):
"""Export this RSA key.
Args:
format (string):
The format to use for wrapping the key:
- *'PEM'*. (*Default*) Text encoding, done according to `RFC1421`_/`RFC1423`_.
- *'DER'*. Binary encoding.
- *'OpenSSH'*. Textual encoding, done according to OpenSSH specification.
Only suitable for public keys (not private keys).
passphrase (string):
(*For private keys only*) The pass phrase used for protecting the output.
pkcs (integer):
(*For private keys only*) The ASN.1 structure to use for
serializing the key. Note that even in case of PEM
encoding, there is an inner ASN.1 DER structure.
With ``pkcs=1`` (*default*), the private key is encoded in a
simple `PKCS#1`_ structure (``RSAPrivateKey``).
With ``pkcs=8``, the private key is encoded in a `PKCS#8`_ structure
(``PrivateKeyInfo``).
.. note::
This parameter is ignored for a public key.
For DER and PEM, an ASN.1 DER ``SubjectPublicKeyInfo``
structure is always used.
protection (string):
(*For private keys only*)
The encryption scheme to use for protecting the private key.
If ``None`` (default), the behavior depends on :attr:`format`:
- For *'DER'*, the *PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC*
scheme is used. The following operations are performed:
1. A 16 byte Triple DES key is derived from the passphrase
using :func:`Cryptodome.Protocol.KDF.PBKDF2` with 8 bytes salt,
and 1 000 iterations of :mod:`Cryptodome.Hash.HMAC`.
2. The private key is encrypted using CBC.
3. The encrypted key is encoded according to PKCS#8.
- For *'PEM'*, the obsolete PEM encryption scheme is used.
It is based on MD5 for key derivation, and Triple DES for encryption.
Specifying a value for :attr:`protection` is only meaningful for PKCS#8
(that is, ``pkcs=8``) and only if a pass phrase is present too.
The supported schemes for PKCS#8 are listed in the
:mod:`Cryptodome.IO.PKCS8` module (see :attr:`wrap_algo` parameter).
randfunc (callable):
A function that provides random bytes. Only used for PEM encoding.
The default is :func:`Cryptodome.Random.get_random_bytes`.
Returns:
byte string: the encoded key
Raises:
ValueError:when the format is unknown or when you try to encrypt a private
key with *DER* format and PKCS#1.
.. warning::
If you don't provide a pass phrase, the private key will be
exported in the clear!
.. _RFC1421: http://www.ietf.org/rfc/rfc1421.txt
.. _RFC1423: http://www.ietf.org/rfc/rfc1423.txt
.. _`PKCS#1`: http://www.ietf.org/rfc/rfc3447.txt
.. _`PKCS#8`: http://www.ietf.org/rfc/rfc5208.txt
"""
if passphrase is not None:
passphrase = tobytes(passphrase)
if randfunc is None:
randfunc = Random.get_random_bytes
if format == 'OpenSSH':
e_bytes, n_bytes = [x.to_bytes() for x in (self._e, self._n)]
if bord(e_bytes[0]) & 0x80:
e_bytes = bchr(0) + e_bytes
if bord(n_bytes[0]) & 0x80:
n_bytes = bchr(0) + n_bytes
keyparts = [b('ssh-rsa'), e_bytes, n_bytes]
keystring = b('').join(
[struct.pack(">I", len(kp)) + kp for kp in keyparts])
return b('ssh-rsa ') + binascii.b2a_base64(keystring)[:-1]
# DER format is always used, even in case of PEM, which simply
# encodes it into BASE64.
if self.has_private():
binary_key = DerSequence([
0, self.n, self.e, self.d, self.p, self.q,
self.d % (self.p - 1), self.d % (self.q - 1),
Integer(self.q).inverse(self.p)
]).encode()
if pkcs == 1:
key_type = 'RSA PRIVATE KEY'
if format == 'DER' and passphrase:
raise ValueError("PKCS#1 private key cannot be encrypted")
else: # PKCS#8
if format == 'PEM' and protection is None:
key_type = 'PRIVATE KEY'
binary_key = PKCS8.wrap(binary_key, oid, None)
else:
key_type = 'ENCRYPTED PRIVATE KEY'
if not protection:
protection = 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC'
binary_key = PKCS8.wrap(binary_key, oid, passphrase,
protection)
passphrase = None
else:
key_type = "PUBLIC KEY"
binary_key = _create_subject_public_key_info(
oid, DerSequence([self.n, self.e]))
if format == 'DER':
return binary_key
if format == 'PEM':
pem_str = PEM.encode(binary_key, key_type, passphrase, randfunc)
return tobytes(pem_str)
raise ValueError(
"Unknown key format '%s'. Cannot export the RSA key." % format)
def testEncode3(self):
# One multi-byte integer (non-zero)
der = DerSequence()
der.append(0x180L)
self.assertEquals(der.encode(), b('0\x04\x02\x02\x01\x80'))
def encrypt(data, passphrase, protection, prot_params=None, randfunc=None):
"""Encrypt a piece of data using a passphrase and *PBES2*.
:Parameters:
data : byte string
The piece of data to encrypt.
passphrase : byte string
The passphrase to use for encrypting the data.
protection : string
The identifier of the encryption algorithm to use.
The default value is '``PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC``'.
prot_params : dictionary
Parameters of the protection algorithm.
+------------------+-----------------------------------------------+
| Key | Description |
+==================+===============================================+
| iteration_count | The KDF algorithm is repeated several times to|
| | slow down brute force attacks on passwords |
| | (called *N* or CPU/memory cost in scrypt). |
| | |
| | The default value for PBKDF2 is 1 000. |
| | The default value for scrypt is 16 384. |
+------------------+-----------------------------------------------+
| salt_size | Salt is used to thwart dictionary and rainbow |
| | attacks on passwords. The default value is 8 |
| | bytes. |
+------------------+-----------------------------------------------+
| block_size | *(scrypt only)* Memory-cost (r). The default |
| | value is 8. |
+------------------+-----------------------------------------------+
| parallelization | *(scrypt only)* CPU-cost (p). The default |
| | value is 1. |
+------------------+-----------------------------------------------+
randfunc : callable
Random number generation function; it should accept
a single integer N and return a string of random data,
N bytes long. If not specified, a new RNG will be
instantiated from ``Cryptodome.Random``.
:Returns:
The encrypted data, as a binary string.
"""
if prot_params is None:
prot_params = {}
if randfunc is None:
randfunc = Random.new().read
if protection == 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC':
key_size = 24
module = DES3
cipher_mode = DES3.MODE_CBC
enc_oid = _OID_DES_EDE3_CBC
elif protection in ('PBKDF2WithHMAC-SHA1AndAES128-CBC',
'scryptAndAES128-CBC'):
key_size = 16
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = _OID_AES128_CBC
elif protection in ('PBKDF2WithHMAC-SHA1AndAES192-CBC',
'scryptAndAES192-CBC'):
key_size = 24
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = _OID_AES192_CBC
elif protection in ('PBKDF2WithHMAC-SHA1AndAES256-CBC',
'scryptAndAES256-CBC'):
key_size = 32
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = _OID_AES256_CBC
else:
raise ValueError("Unknown PBES2 mode")
# Get random data
iv = randfunc(module.block_size)
salt = randfunc(prot_params.get("salt_size", 8))
# Derive key from password
if protection.startswith('PBKDF2'):
count = prot_params.get("iteration_count", 1000)
key = PBKDF2(passphrase, salt, key_size, count)
kdf_info = DerSequence([
DerObjectId(_OID_PBKDF2), # PBKDF2
DerSequence([DerOctetString(salt),
DerInteger(count)])
])
else:
# It must be scrypt
count = prot_params.get("iteration_count", 16384)
scrypt_r = prot_params.get('block_size', 8)
scrypt_p = prot_params.get('parallelization', 1)
key = scrypt(passphrase, salt, key_size, count, scrypt_r, scrypt_p)
kdf_info = DerSequence([
DerObjectId(_OID_SCRYPT), # scrypt
DerSequence([
DerOctetString(salt),
DerInteger(count),
DerInteger(scrypt_r),
DerInteger(scrypt_p)
])
])
# Create cipher and use it
cipher = module.new(key, cipher_mode, iv)
encrypted_data = cipher.encrypt(pad(data, cipher.block_size))
enc_info = DerSequence([DerObjectId(enc_oid), DerOctetString(iv)])
# Result
enc_private_key_info = DerSequence([
# encryptionAlgorithm
DerSequence([
DerObjectId(_OID_PBES2),
DerSequence([kdf_info, enc_info]),
]),
DerOctetString(encrypted_data)
])
return enc_private_key_info.encode()
def decrypt(data, passphrase):
"""Decrypt a piece of data using a passphrase and *PBES2*.
The algorithm to use is automatically detected.
:Parameters:
data : byte string
The piece of data to decrypt.
passphrase : byte string
The passphrase to use for decrypting the data.
:Returns:
The decrypted data, as a binary string.
"""
enc_private_key_info = DerSequence().decode(data, nr_elements=2)
enc_algo = DerSequence().decode(enc_private_key_info[0])
encrypted_data = DerOctetString().decode(
enc_private_key_info[1]).payload
pbe_oid = DerObjectId().decode(enc_algo[0]).value
if pbe_oid != _OID_PBES2:
raise PbesError("Not a PBES2 object")
pbes2_params = DerSequence().decode(enc_algo[1], nr_elements=2)
### Key Derivation Function selection
kdf_info = DerSequence().decode(pbes2_params[0], nr_elements=2)
kdf_oid = DerObjectId().decode(kdf_info[0]).value
kdf_key_length = None
# We only support PBKDF2 or scrypt
if kdf_oid == _OID_PBKDF2:
pbkdf2_params = DerSequence().decode(kdf_info[1],
nr_elements=(2, 3, 4))
salt = DerOctetString().decode(pbkdf2_params[0]).payload
iteration_count = pbkdf2_params[1]
left = len(pbkdf2_params) - 2
idx = 2
if left > 0:
try:
kdf_key_length = pbkdf2_params[idx] - 0
left -= 1
idx += 1
except TypeError:
pass
# Default is HMAC-SHA1
pbkdf2_prf_oid = "1.2.840.113549.2.7"
if left > 0:
pbkdf2_prf_algo_id = DerSequence().decode(pbkdf2_params[idx])
pbkdf2_prf_oid = DerObjectId().decode(
pbkdf2_prf_algo_id[0]).value
elif kdf_oid == _OID_SCRYPT:
scrypt_params = DerSequence().decode(kdf_info[1],
nr_elements=(4, 5))
salt = DerOctetString().decode(scrypt_params[0]).payload
iteration_count, scrypt_r, scrypt_p = [
scrypt_params[x] for x in (1, 2, 3)
]
if len(scrypt_params) > 4:
kdf_key_length = scrypt_params[4]
else:
kdf_key_length = None
else:
raise PbesError("Unsupported PBES2 KDF")
### Cipher selection
enc_info = DerSequence().decode(pbes2_params[1])
enc_oid = DerObjectId().decode(enc_info[0]).value
if enc_oid == _OID_DES_EDE3_CBC:
# DES_EDE3_CBC
ciphermod = DES3
key_size = 24
elif enc_oid == _OID_AES128_CBC:
# AES128_CBC
ciphermod = AES
key_size = 16
elif enc_oid == _OID_AES192_CBC:
# AES192_CBC
ciphermod = AES
key_size = 24
elif enc_oid == _OID_AES256_CBC:
# AES256_CBC
ciphermod = AES
key_size = 32
else:
raise PbesError("Unsupported PBES2 cipher")
if kdf_key_length and kdf_key_length != key_size:
raise PbesError("Mismatch between PBES2 KDF parameters"
" and selected cipher")
IV = DerOctetString().decode(enc_info[1]).payload
# Create cipher
if kdf_oid == _OID_PBKDF2:
if pbkdf2_prf_oid == _OID_HMAC_SHA1:
hmac_hash_module = SHA1
elif pbkdf2_prf_oid == _OID_HMAC_SHA224:
hmac_hash_module = SHA224
elif pbkdf2_prf_oid == _OID_HMAC_SHA256:
hmac_hash_module = SHA256
elif pbkdf2_prf_oid == _OID_HMAC_SHA384:
hmac_hash_module = SHA384
elif pbkdf2_prf_oid == _OID_HMAC_SHA512:
hmac_hash_module = SHA512
else:
raise PbesError("Unsupported HMAC %s" % pbkdf2_prf_oid)
key = PBKDF2(passphrase,
salt,
key_size,
iteration_count,
hmac_hash_module=hmac_hash_module)
else:
key = scrypt(passphrase, salt, key_size, iteration_count, scrypt_r,
scrypt_p)
cipher = ciphermod.new(key, ciphermod.MODE_CBC, IV)
# Decrypt data
pt = cipher.decrypt(encrypted_data)
return unpad(pt, cipher.block_size)
def testDecode9(self):
# Verify that decode returns itself
der = DerSequence()
self.assertEqual(der, der.decode(b('0\x06\x24\x02\xb6\x63\x12\x00')))
def _EMSA_PKCS1_V1_5_ENCODE(msg_hash, emLen, with_hash_parameters=True):
"""
Implement the ``EMSA-PKCS1-V1_5-ENCODE`` function, as defined
in PKCS#1 v2.1 (RFC3447, 9.2).
``_EMSA-PKCS1-V1_5-ENCODE`` actually accepts the message ``M`` as input,
and hash it internally. Here, we expect that the message has already
been hashed instead.
:Parameters:
msg_hash : hash object
The hash object that holds the digest of the message being signed.
emLen : int
The length the final encoding must have, in bytes.
with_hash_parameters : bool
If True (default), include NULL parameters for the hash
algorithm in the ``digestAlgorithm`` SEQUENCE.
:attention: the early standard (RFC2313) stated that ``DigestInfo``
had to be BER-encoded. This means that old signatures
might have length tags in indefinite form, which
is not supported in DER. Such encoding cannot be
reproduced by this function.
:Return: An ``emLen`` byte long string that encodes the hash.
"""
# First, build the ASN.1 DER object DigestInfo:
#
# DigestInfo ::= SEQUENCE {
# digestAlgorithm AlgorithmIdentifier,
# digest OCTET STRING
# }
#
# where digestAlgorithm identifies the hash function and shall be an
# algorithm ID with an OID in the set PKCS1-v1-5DigestAlgorithms.
#
# PKCS1-v1-5DigestAlgorithms ALGORITHM-IDENTIFIER ::= {
# { OID id-md2 PARAMETERS NULL }|
# { OID id-md5 PARAMETERS NULL }|
# { OID id-sha1 PARAMETERS NULL }|
# { OID id-sha256 PARAMETERS NULL }|
# { OID id-sha384 PARAMETERS NULL }|
# { OID id-sha512 PARAMETERS NULL }
# }
#
# Appendix B.1 also says that for SHA-1/-2 algorithms, the parameters
# should be omitted. They may be present, but when they are, they shall
# have NULL value.
digestAlgo = DerSequence([ DerObjectId(msg_hash.oid).encode() ])
if with_hash_parameters:
digestAlgo.append(DerNull().encode())
digest = DerOctetString(msg_hash.digest())
digestInfo = DerSequence([
digestAlgo.encode(),
digest.encode()
]).encode()
# We need at least 11 bytes for the remaining data: 3 fixed bytes and
# at least 8 bytes of padding).
if emLen<len(digestInfo)+11:
raise TypeError("Selected hash algorith has a too long digest (%d bytes)." % len(digest))
PS = bchr(0xFF) * (emLen - len(digestInfo) - 3)
return b("\x00\x01") + PS + bchr(0x00) + digestInfo
def encrypt(data, passphrase, protection, prot_params=None, randfunc=None):
"""Encrypt a piece of data using a passphrase and *PBES2*.
:Parameters:
data : byte string
The piece of data to encrypt.
passphrase : byte string
The passphrase to use for encrypting the data.
protection : string
The identifier of the encryption algorithm to use.
The default value is '``PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC``'.
prot_params : dictionary
Parameters of the protection algorithm.
+------------------+-----------------------------------------------+
| Key | Description |
+==================+===============================================+
| iteration_count | The KDF algorithm is repeated several times to|
| | slow down brute force attacks on passwords |
| | (called *N* or CPU/memory cost in scrypt). |
| | |
| | The default value for PBKDF2 is 1 000. |
| | The default value for scrypt is 16 384. |
+------------------+-----------------------------------------------+
| salt_size | Salt is used to thwart dictionary and rainbow |
| | attacks on passwords. The default value is 8 |
| | bytes. |
+------------------+-----------------------------------------------+
| block_size | *(scrypt only)* Memory-cost (r). The default |
| | value is 8. |
+------------------+-----------------------------------------------+
| parallelization | *(scrypt only)* CPU-cost (p). The default |
| | value is 1. |
+------------------+-----------------------------------------------+
randfunc : callable
Random number generation function; it should accept
a single integer N and return a string of random data,
N bytes long. If not specified, a new RNG will be
instantiated from ``Cryptodome.Random``.
:Returns:
The encrypted data, as a binary string.
"""
if prot_params is None:
prot_params = {}
if randfunc is None:
randfunc = Random.new().read
if protection == 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC':
key_size = 24
module = DES3
cipher_mode = DES3.MODE_CBC
enc_oid = "1.2.840.113549.3.7"
elif protection in ('PBKDF2WithHMAC-SHA1AndAES128-CBC',
'scryptAndAES128-CBC'):
key_size = 16
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = "2.16.840.1.101.3.4.1.2"
elif protection in ('PBKDF2WithHMAC-SHA1AndAES192-CBC',
'scryptAndAES192-CBC'):
key_size = 24
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = "2.16.840.1.101.3.4.1.22"
elif protection in ('PBKDF2WithHMAC-SHA1AndAES256-CBC',
'scryptAndAES256-CBC'):
key_size = 32
module = AES
cipher_mode = AES.MODE_CBC
enc_oid = "2.16.840.1.101.3.4.1.42"
else:
raise ValueError("Unknown PBES2 mode")
# Get random data
iv = randfunc(module.block_size)
salt = randfunc(prot_params.get("salt_size", 8))
# Derive key from password
if protection.startswith('PBKDF2'):
count = prot_params.get("iteration_count", 1000)
key = PBKDF2(passphrase, salt, key_size, count)
kdf_info = DerSequence([
DerObjectId("1.2.840.113549.1.5.12"), # PBKDF2
DerSequence([
DerOctetString(salt),
DerInteger(count)
])
])
else:
# It must be scrypt
count = prot_params.get("iteration_count", 16384)
scrypt_r = prot_params.get('block_size', 8)
scrypt_p = prot_params.get('parallelization', 1)
key = scrypt(passphrase, salt, key_size,
count, scrypt_r, scrypt_p)
kdf_info = DerSequence([
DerObjectId("1.3.6.1.4.1.11591.4.11"), # scrypt
DerSequence([
DerOctetString(salt),
DerInteger(count),
DerInteger(scrypt_r),
DerInteger(scrypt_p)
])
])
# Create cipher and use it
cipher = module.new(key, cipher_mode, iv)
encrypted_data = cipher.encrypt(pad(data, cipher.block_size))
enc_info = DerSequence([
DerObjectId(enc_oid),
DerOctetString(iv)
])
# Result
enc_private_key_info = DerSequence([
# encryptionAlgorithm
DerSequence([
DerObjectId("1.2.840.113549.1.5.13"), # PBES2
DerSequence([
kdf_info,
enc_info
]),
]),
DerOctetString(encrypted_data)
])
return enc_private_key_info.encode()
def testEncode1(self):
# Empty sequence
der = DerSequence()
self.assertEquals(der.encode(), b('0\x00'))
self.failIf(der.hasOnlyInts())
# One single-byte integer (zero)
der.append(0)
self.assertEquals(der.encode(), b('0\x03\x02\x01\x00'))
self.assertEquals(der.hasInts(),1)
self.assertEquals(der.hasInts(False),1)
self.failUnless(der.hasOnlyInts())
self.failUnless(der.hasOnlyInts(False))
# Invariant
self.assertEquals(der.encode(), b('0\x03\x02\x01\x00'))
def testInit1(self):
der = DerSequence([1, DerInteger(2), b('0\x00')])
self.assertEquals(der.encode(), b('0\x08\x02\x01\x01\x02\x01\x020\x00'))
def wrap(private_key, key_oid, passphrase=None, protection=None,
prot_params=None, key_params=None, randfunc=None):
"""Wrap a private key into a PKCS#8 blob (clear or encrypted).
:Parameters:
private_key : byte string
The private key encoded in binary form. The actual encoding is
algorithm specific. In most cases, it is DER.
key_oid : string
The object identifier (OID) of the private key to wrap.
It is a dotted string, like "``1.2.840.113549.1.1.1``" (for RSA keys).
passphrase : (binary) string
The secret passphrase from which the wrapping key is derived.
Set it only if encryption is required.
protection : string
The identifier of the algorithm to use for securely wrapping the key.
The default value is '``PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC``'.
prot_params : dictionary
Parameters for the protection algorithm.
+------------------+-----------------------------------------------+
| Key | Description |
+==================+===============================================+
| iteration_count | The KDF algorithm is repeated several times to|
| | slow down brute force attacks on passwords |
| | (called *N* or CPU/memory cost in scrypt). |
| | |
| | The default value for PBKDF2 is 1 000. |
| | The default value for scrypt is 16 384. |
+------------------+-----------------------------------------------+
| salt_size | Salt is used to thwart dictionary and rainbow |
| | attacks on passwords. The default value is 8 |
| | bytes. |
+------------------+-----------------------------------------------+
| block_size | *(scrypt only)* Memory-cost (r). The default |
| | value is 8. |
+------------------+-----------------------------------------------+
| parallelization | *(scrypt only)* CPU-cost (p). The default |
| | value is 1. |
+------------------+-----------------------------------------------+
key_params : DER object
The algorithm parameters associated to the private key.
It is required for algorithms like DSA, but not for others like RSA.
randfunc : callable
Random number generation function; it should accept a single integer
N and return a string of random data, N bytes long.
If not specified, a new RNG will be instantiated
from ``Cryptodome.Random``.
:Return:
The PKCS#8-wrapped private key (possibly encrypted),
as a binary string.
"""
if key_params is None:
key_params = DerNull()
#
# PrivateKeyInfo ::= SEQUENCE {
# version Version,
# privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
# privateKey PrivateKey,
# attributes [0] IMPLICIT Attributes OPTIONAL
# }
#
pk_info = DerSequence([
0,
DerSequence([
DerObjectId(key_oid),
key_params
]),
DerOctetString(private_key)
])
pk_info_der = pk_info.encode()
if passphrase is None:
return pk_info_der
if not passphrase:
raise ValueError("Empty passphrase")
# Encryption with PBES2
passphrase = tobytes(passphrase)
if protection is None:
protection = 'PBKDF2WithHMAC-SHA1AndDES-EDE3-CBC'
return PBES2.encrypt(pk_info_der, passphrase,
protection, prot_params, randfunc)
def testEncode6(self):
# Two positive integers
der = DerSequence()
der.append(0x180L)
der.append(0xFFL)
self.assertEquals(der.encode(), b('0\x08\x02\x02\x01\x80\x02\x02\x00\xff'))
self.failUnless(der.hasOnlyInts())
self.failUnless(der.hasOnlyInts(False))
# Two mixed integers
der = DerSequence()
der.append(2)
der.append(-2)
self.assertEquals(der.encode(), b('0\x06\x02\x01\x02\x02\x01\xFE'))
self.assertEquals(der.hasInts(), 1)
self.assertEquals(der.hasInts(False), 2)
self.failIf(der.hasOnlyInts())
self.failUnless(der.hasOnlyInts(False))
#
der.append(0x01)
der[1:] = [9,8]
self.assertEquals(len(der),3)
self.assertEqual(der[1:],[9,8])
self.assertEqual(der[1:-1],[9])
self.assertEquals(der.encode(), b('0\x09\x02\x01\x02\x02\x01\x09\x02\x01\x08'))