def find_hash_name(security_infos: List[bytes]) -> str:
"""
Return the hashing algorithm for ECC AA from SecurityInfos (DG14)
"""
for sec_info in security_infos:
i = asn1_node_root(sec_info)
i = asn1_node_first_child(sec_info, i) # get OID for this SecurityInfo
si_oid = asn1_get_all(sec_info, i)
if si_oid != encode_oid_string(
"2.23.136.1.1.5"): # id-icao-mrtd-security-aaProtocolObject
continue
i = asn1_node_next(sec_info, i)
if asn1_get_value_of_type(sec_info, i, "INTEGER") != b"\x01":
raise ValueError("[-] Version mismatch in DG14 AA SecurityInfo!")
i = asn1_node_next(sec_info, i)
signature_algorithm = asn1_get_all(sec_info, i)
if signature_algorithm == encode_oid_string("0.4.0.127.0.7.1.1.4.1.2"):
return "sha224"
if signature_algorithm == encode_oid_string("0.4.0.127.0.7.1.1.4.1.3"):
return "sha256"
if signature_algorithm == encode_oid_string("0.4.0.127.0.7.1.1.4.1.4"):
return "sha384"
if signature_algorithm == encode_oid_string("0.4.0.127.0.7.1.1.4.1.5"):
return "sha512"
raise ValueError("[-] Unsupported signature algorithm in AA SecurityInfo!")
def find_paceinfos(security_infos: List[bytes]) -> List[Tuple[bytes, int]]:
"""
From SecurityInfos find Chip Authentication Public Keys and return them as\n
list(list(key_id, pub_key))\n
If key id doesn't exist, it is an empty bytes b""
"""
id_pace = "0.4.0.127.0.7.2.2.4"
pace_protocol_dict = {
encode_oid_string(id_pace + ".1.1"): "id-PACE-DH-GM-3DES-CBC-CBC",
encode_oid_string(id_pace + ".1.2"): "id-PACE-DH-GM-AES-CBC-CMAC-128",
encode_oid_string(id_pace + ".1.3"): "id-PACE-DH-GM-AES-CBC-CMAC-192",
encode_oid_string(id_pace + ".1.4"): "id-PACE-DH-GM-AES-CBC-CMAC-256",
encode_oid_string(id_pace + ".2.1"): "id-PACE-ECDH-GM-3DES-CBC-CBC",
encode_oid_string(id_pace + ".2.2"): "id-PACE-ECDH-GM-AES-CBC-CMAC-128",
encode_oid_string(id_pace + ".2.3"): "id-PACE-ECDH-GM-AES-CBC-CMAC-192",
encode_oid_string(id_pace + ".2.4"): "id-PACE-ECDH-GM-AES-CBC-CMAC-256",
encode_oid_string(id_pace + ".3.1"): "id-PACE-DH-IM-3DES-CBC-CBC",
encode_oid_string(id_pace + ".3.2"): "id-PACE-DH-IM-AES-CBC-CMAC-128",
encode_oid_string(id_pace + ".3.3"): "id-PACE-DH-IM-AES-CBC-CMAC-192",
encode_oid_string(id_pace + ".3.4"): "id-PACE-DH-IM-AES-CBC-CMAC-256",
encode_oid_string(id_pace + ".4.1"): "id-PACE-ECDH-IM-3DES-CBC-CBC",
encode_oid_string(id_pace + ".4.2"): "id-PACE-ECDH-IM-AES-CBC-CMAC-128",
encode_oid_string(id_pace + ".4.3"): "id-PACE-ECDH-IM-AES-CBC-CMAC-192",
encode_oid_string(id_pace + ".4.4"): "id-PACE-ECDH-IM-AES-CBC-CMAC-256",
encode_oid_string(id_pace + ".6.2"): "id-PACE-ECDH-CAM-AES-CBC-CMAC-128",
encode_oid_string(id_pace + ".6.3"): "id-PACE-ECDH-CAM-AES-CBC-CMAC-192",
encode_oid_string(id_pace + ".6.4"): "id-PACE-ECDH-CAM-AES-CBC-CMAC-256",
}
supported_pace: List[Tuple[bytes, int]] = []
for sec_info in security_infos:
i = asn1_node_root(sec_info)
i = asn1_node_first_child(sec_info, i) # get OID for this SecurityInfo
si_oid = asn1_get_all(sec_info, i)
if si_oid not in pace_protocol_dict:
continue
i = asn1_node_next(sec_info, i) # get version for this PACEInfo
si_ver = asn1_get_value_of_type(sec_info, i, "INTEGER")
if si_ver != b"\x02": # Other versions are not supported
continue
i = asn1_node_next(sec_info, i) # get parameterID for this PACEInfo
si_parameter_info = int.from_bytes(
asn1_get_value_of_type(sec_info, i, "INTEGER"), byteorder="big"
)
supported_pace.append((si_oid, si_parameter_info))
return supported_pace
def extract_certificates(signed_data: bytes) -> List[X509]:
"""
Return CSCA certificates from Master List
"""
certs = []
i = asn1_node_root(signed_data)
last_byte = i[2]
i = asn1_node_first_child(signed_data, i)
i = asn1_node_next(signed_data, i)
i = asn1_node_first_child(signed_data, i)
while True:
data = asn1_get_all(signed_data, i)
certs.append(load_certificate(FILETYPE_ASN1, data))
if i[2] == last_byte:
break
i = asn1_node_next(signed_data, i)
print(f"\t[+] Extracted {len(certs)} certs")
return certs
def parse_efcom(efcom: bytes) -> Dict[bytes, str]:
"""
Parse EF.COM file and return the files mentioned as a dict
"""
i = asn1_node_root(efcom)
lst = list(i)
# LDS Version length is 4
lst[0] = lst[1]
lst[1] = lst[0] + 3
lst[2] = lst[1] + 3
i = (lst[0], lst[1], lst[2])
lds_ver = asn1_get_value(efcom, i)
print("[+] LDS version: {}.{}".format(
*[int(lds_ver[i:i + 2].decode("utf-8")) for i in range(0, 4, 2)]))
# Unicode Version number length is 6
lst[0] = lst[2] + 1
lst[1] = lst[0] + 3
lst[2] = lst[1] + 5
i = (lst[0], lst[1], lst[2])
unicode_ver = asn1_get_value(efcom, i)
print("[+] Unicode version: {}.{}.{}".format(
*[int(unicode_ver[i:i + 2].decode("utf-8")) for i in range(0, 6, 2)]))
i = asn1_node_next(efcom, i)
rest = asn1_get_value(efcom, i)
tag2dg: Dict[int, Tuple[bytes, str]] = {
0x60: (b"\x1E", "EF.COM"),
0x61: (b"\x01", "EF.DG1"),
0x75: (b"\x02", "EF.DG2"),
0x63: (b"\x03", "EF.DG3"),
0x76: (b"\x04", "EF.DG4"),
0x65: (b"\x05", "EF.DG5"),
0x66: (b"\x06", "EF.DG6"),
0x67: (b"\x07", "EF.DG7"),
0x68: (b"\x08", "EF.DG8"),
0x69: (b"\x09", "EF.DG9"),
0x6A: (b"\x0A", "EF.DG10"),
0x6B: (b"\x0B", "EF.DG11"),
0x6C: (b"\x0C", "EF.DG12"),
0x6D: (b"\x0D", "EF.DG13"),
0x6E: (b"\x0E", "EF.DG14"),
0x6F: (b"\x0F", "EF.DG15"),
0x70: (b"\x10", "EF.DG16"),
0x77: (b"\x1D", "EF.SOD"),
}
dg_list = {tag2dg[byte][0]: tag2dg[byte][1] for byte in rest}
return dg_list
def add_seconds_to_certificate(cert: bytes, seconds: int) -> bytes:
from datetime import datetime, timedelta
i = asn1_node_root(cert) # Certificate
i = asn1_node_first_child(cert, i) # tbsCertificate
i = asn1_node_first_child(cert, i) # version
i = asn1_node_next(cert, i) # serialNumber
i = asn1_node_next(cert, i) # signature
i = asn1_node_next(cert, i) # issuer
i = asn1_node_next(cert, i) # validity
i = asn1_node_first_child(cert, i) # notBefore
not_before = asn1_get_value(cert, i)
if len(not_before) == 13:
date_format = "%y%m%d%H%M%SZ"
else:
date_format = "%Y%m%d%H%M%SZ"
date_time_obj = datetime.strptime(not_before.decode("utf-8"), date_format)
cert = (
cert[:i[1]] +
(date_time_obj +
timedelta(seconds=seconds)).strftime(date_format).encode("utf_8") +
cert[i[2] + 1:])
i = asn1_node_next(cert, i) # notAfter
not_after = asn1_get_value(cert, i)
if len(not_after) == 13:
date_format = "%y%m%d%H%M%SZ"
else:
date_format = "%Y%m%d%H%M%SZ"
date_time_obj = datetime.strptime(not_after.decode("utf-8"), date_format)
cert = (
cert[:i[1]] +
(date_time_obj +
timedelta(seconds=seconds)).strftime(date_format).encode("utf_8") +
cert[i[2] + 1:])
return cert
def assert_dg_hash(dg_file: bytes, data_group_hash_values: bytes,
hash_alg: str, dg_number_bytes: bytes) -> bool:
"""
Calculate the hash over the DG file and compare that in the EF.SOD.
"""
dg_number = int.from_bytes(dg_number_bytes, byteorder="big")
# Only hashes for DG1-DG16 exist
if dg_number < 1 and dg_number > 16:
raise ValueError("[-] Only hashes for DG1-DG16 exist!")
hash_object = hashlib.new(hash_alg)
hash_object.update(dg_file)
file_hash = hash_object.digest()
current = 0
i = asn1_node_root(data_group_hash_values)
i = asn1_node_first_child(data_group_hash_values, i)
while True:
j = asn1_node_first_child(data_group_hash_values, i)
current = int.from_bytes(
asn1_get_value_of_type(data_group_hash_values, j, "INTEGER"),
byteorder="big",
)
if current == dg_number:
break
i = asn1_node_next(data_group_hash_values, i)
j = asn1_node_next(data_group_hash_values, j)
hash_in_dg = asn1_get_value(data_group_hash_values, j)
if not hmac.compare_digest(file_hash, hash_in_dg):
print("[-] Potentially cloned document, hashes do not match!")
return False
print(f"[+] DG {dg_number} hash matches that on the EF.SOD.")
return True
def get_dg_numbers(data_group_hash_values: bytes) -> Dict[bytes, str]:
"""
Get DG numbers from EF.SOD data group hash values.
"""
dg_list = []
i = asn1_node_root(data_group_hash_values)
last = i[2]
i = asn1_node_first_child(data_group_hash_values, i)
j = asn1_node_first_child(data_group_hash_values, i)
dg_list.append(asn1_get_value_of_type(data_group_hash_values, j,
"INTEGER"))
while i[2] != last:
i = asn1_node_next(data_group_hash_values, i)
j = asn1_node_first_child(data_group_hash_values, i)
dg_list.append(
asn1_get_value_of_type(data_group_hash_values, j, "INTEGER"))
tag2dg: Dict[bytes, str] = {
b"\x1E": "EF.COM",
b"\x01": "EF.DG1",
b"\x02": "EF.DG2",
b"\x03": "EF.DG3",
b"\x04": "EF.DG4",
b"\x05": "EF.DG5",
b"\x06": "EF.DG6",
b"\x07": "EF.DG7",
b"\x08": "EF.DG8",
b"\x09": "EF.DG9",
b"\x0A": "EF.DG10",
b"\x0B": "EF.DG11",
b"\x0C": "EF.DG12",
b"\x0D": "EF.DG13",
b"\x0E": "EF.DG14",
b"\x0F": "EF.DG15",
b"\x10": "EF.DG16",
b"\x1D": "EF.SOD",
}
return {byte: tag2dg[byte] for byte in dg_list}
def parse_security_infos(dg14: bytes) -> List[bytes]:
"""
Return a list of SecurityInfo from SecurityInfos
"""
i = asn1_node_root(dg14)
if dg14[0] == 0x6E: # strip DG14 tag (6E)
i = asn1_node_first_child(dg14, i)
last_byte = i[2]
security_infos = []
i = asn1_node_first_child(dg14, i)
security_infos.append(asn1_get_all(dg14, i))
if i[2] != last_byte:
while True:
i = asn1_node_next(dg14, i)
security_infos.append(asn1_get_all(dg14, i))
if i[2] == last_byte:
break
return security_infos
def passive_auth(
efsod: bytes,
ee_deviant_doc: bool = False,
dump: bool = False
) -> Tuple[str, bytes, bytes, Optional[List[PassiveAuthenticationError]]]:
"""
Do Passive Authentication
:returns:
hash_alg that is used to hash DGs,
data_group_hash_values
"""
exceptions: List[PassiveAuthenticationError] = []
# get root node
i = asn1_node_root(efsod)
# unpack application data 0x77
i = asn1_node_first_child(efsod, i)
# unpack sequence
i = asn1_node_first_child(efsod, i)
# print id-signedData OBJECT IDENTIFIER
if dump:
print(dump_asn1(asn1_get_all(efsod, i)))
# get 2nd item inside (SignedData EXPLICIT tagged)
i = asn1_node_next(efsod, i)
# unpack SignedData EXPLICIT tag
i = asn1_node_first_child(efsod, i)
# get 1st item inside (CMSVersion Value = v3)
i = asn1_node_first_child(efsod, i)
# get 2nd item (DigestAlgorithmIdentifiers) collection of message digest algorithm identifiers.
# There MAY be any number of elements in the collection, including zero.
i = asn1_node_next(efsod, i)
# get 3rd item (EncapsulatedContentInfo) (LDS Document Security Object)
i = asn1_node_next(efsod, i)
# get 1st item inside (eContentType)
# (OID joint-iso-itu-t (2) international(23) icao(136) mrtd(1) security(1) ldsSecurityObject(1))
j = asn1_node_first_child(efsod, i)
e_content_type = asn1_get_all(efsod, j)
# get the EXPLICIT tagged encoded contents of ldsSecurityObject
j = asn1_node_next(efsod, j)
# get the encoded contents of ldsSecurityObject
j = asn1_node_first_child(efsod, j)
# print the value of eContent hash
encapsulated_content = asn1_get_value_of_type(efsod, j, "OCTET STRING")
del j
signer_infos, certificates, crls = None, None, None
while signer_infos is None:
# https://stackoverflow.com/a/52041365/6077951
# get 4th item
i = asn1_node_next(efsod, i)
if efsod[i[0]] == 0xA0:
# Constructed, Context-Specific 0
certificates = i
print("[+] CertificateSet exist")
elif efsod[i[0]] == 0xA1:
# Constructed, Context-Specific 1
crls = i
print("[+] Crls exist")
else:
signer_infos = i
# The inspection system SHALL build and validate a certification path
# from a Trust Anchor to the Document Signer Certificate used to
# sign the Document Security Object (SOD) according to Doc 9303-11.
# store was already built in the first run
store = build_store.store
doc_sig_cert = asn1_get_value(efsod, certificates)
if certificates is not None:
if ee_deviant_doc:
doc_sig_cert = add_seconds_to_certificate(doc_sig_cert, 43200)
CDS = load_certificate(FILETYPE_ASN1, doc_sig_cert)
store_ctx = X509StoreContext(store, CDS)
try:
if store_ctx.verify_certificate() is None:
print(
"[+] Document Signer Certificate is signed by a CSCA certificate"
)
except X509StoreContextError as ex:
exceptions.append(
PassiveAuthenticationError(
"[-] Document Signer Certificate is not signed "
"by a CSCA certificate or is invalid!\n" + str(ex)))
else:
raise PassiveAuthenticationCriticalError(
"[-] This application doesn't support this kind of document yet!")
# get 1st signerInfo inside signerInfos
i = asn1_node_first_child(efsod, signer_infos)
# get 1st item inside 1st signerInfo (CMSVersion)
i = asn1_node_first_child(efsod, i)
signer_info_ver = int.from_bytes(asn1_get_value_of_type(
efsod, i, "INTEGER"),
byteorder="big")
issuer_and_serial_number, subject_key_identifier = None, None
# get 2nd item inside 1st signerInfo (SignerIdentifier)
i = asn1_node_next(efsod, i)
if signer_info_ver == 1:
issuer_and_serial_number = i
elif signer_info_ver == 3:
subject_key_identifier = i
if dump:
print(
dump_asn1(
asn1_get_all(
efsod, issuer_and_serial_number
or subject_key_identifier)))
# get 3rd item inside 1st signerInfo (DigestAlgorithmIdentifier)
i = asn1_node_next(efsod, i)
# get hash algorithm used for encapsulatedContent and SignedAttrs
hash_alg = asn1_get_all(efsod, asn1_node_first_child(efsod, i))
try:
hash_alg = get_digestalg_name(hash_alg)
except ValueError as ex:
raise PassiveAuthenticationCriticalError(
"[-] Hash algorithm is not recognized.") from ex
# get 4th item inside 1st signerInfo ([0] IMPLICIT SignedAttributes)
i = asn1_node_next(efsod, i)
# use EXPLICIT SET OF tag, rather than of the IMPLICIT [0] tag
signed_attrs = asn1_get_all(efsod, i)
signed_attrs = b"\x31" + signed_attrs[1:]
# get the first Attribute from SignedAttributes
j = asn1_node_first_child(efsod, i)
content_type, signed_attrs_hash = None, None
while content_type is None or signed_attrs_hash is None:
# get the content-type and the message-digest
k = asn1_node_first_child(efsod, j)
# contentType
if asn1_get_all(efsod, k) == encode_oid_string("1.2.840.113549.1.9.3"):
# then the content-type attribute value MUST match
# the SignedData encapContentInfo eContentType value.
# checked in line 195
k = asn1_node_next(efsod, k)
k = asn1_node_first_child(efsod, k)
content_type = asn1_get_all(efsod, k)
# messageDigest
elif asn1_get_all(efsod,
k) == encode_oid_string("1.2.840.113549.1.9.4"):
k = asn1_node_next(efsod, k)
k = asn1_node_first_child(efsod, k)
signed_attrs_hash = asn1_get_value_of_type(efsod, k,
"OCTET STRING")
j = asn1_node_next(efsod, j)
del k, j
hash_object = hashlib.new(hash_alg)
hash_object.update(encapsulated_content)
e_content_hash = hash_object.digest()
del hash_object
# print("[+] Calculated hash of eContent =", eContent_hash.hex())
# print("[+] Hash of eContent in SignedAttributes =", signedAttrs_hash.hex())
if e_content_type == content_type:
print(
"[+] Content Type of eContent match with the Content Type in SignedAttributes"
)
else:
exceptions.append(
PassiveAuthenticationError(
"[-] Content Type of eContent DOES NOT "
"match with the Content Type in SignedAttributes."))
if hmac.compare_digest(signed_attrs_hash, e_content_hash):
print("[+] Hash of eContent match with the hash in SignedAttributes")
else:
exceptions.append(
PassiveAuthenticationError(
"[+] Hash of eContent DOES NOT match with the hash in SignedAttributes."
))
# get 4th item inside 1st signerInfo (SignatureAlgorithmIdentifier)
i = asn1_node_next(efsod, i)
# get 5th item inside 1st signerInfo (SignatureValue)
i = asn1_node_next(efsod, i)
signature = asn1_get_value_of_type(efsod, i, "OCTET STRING")
# Verify the signature with DS_cert using hash_alg
try:
if verify(CDS, signature, signed_attrs, hash_alg) is None:
print("[+] The signature on EF_SOD is valid.")
except ex:
exceptions.append(
PassiveAuthenticationError(
"[-] The signature on EF_SOD is not valid or failed."))
i = asn1_node_root(encapsulated_content)
i = asn1_node_first_child(encapsulated_content, i)
i = asn1_node_next(encapsulated_content, i)
i = asn1_node_next(encapsulated_content, i)
data_group_hash_values = asn1_get_all(encapsulated_content, i)
if len(exceptions) == 0:
return hash_alg, data_group_hash_values, doc_sig_cert, None
return hash_alg, data_group_hash_values, doc_sig_cert, exceptions
def process_rapdu(sm_object: SMObject, rapdu: bytes) -> bytes:
"""
Verify the MAC of the received APDU and return the decrypted data if it exists
sm_object -- Necessary secure messaging object (Encryption session key etc.)
rapdu -- Received Reply APDU
:returns: decrypted_data or None
"""
if sm_object.enc_alg is None:
return rapdu
raise ValueError("[-] Encryption algorithm is not set")
if sm_object.mac_alg is None:
raise ValueError("[-] Mac algorithm is not set")
if sm_object.pad_len == 0:
raise ValueError("[-] Padding length is 0")
if sm_object.ks_enc is None or sm_object.ks_mac is None:
raise ValueError("[-] Session keys are not set")
if sm_object.ssc is None:
raise ValueError("[-] SSC is not set")
sm_object.increment_ssc()
encrypted_data, decrypted_data = b"", b""
do85, do87, do99 = None, None, None
i = asn1_node_root(rapdu)
while True:
do = asn1_get_all(rapdu, i)
if do.startswith(b"\x85"):
encrypted_data = asn1_get_value(rapdu, i)
do85 = do
elif do.startswith(b"\x87"):
encrypted_data = asn1_get_value(rapdu, i)
do87 = do
elif do.startswith(b"\x99"):
do99 = do
elif do.startswith(b"\x8E"):
do8e = asn1_get_value(rapdu, i)
if i[2] == len(rapdu) - 1:
break
i = asn1_node_next(rapdu, i)
k = padding_method_2(
sm_object.ssc + (do85 or b"") + (do87 or b"") + (do99 or b""),
sm_object.pad_len)
cc = compute_mac(sm_object.ks_mac, k, sm_object.mac_alg)
if cc != do8e:
raise ReplyAPDUError("[-] Reply APDU is not valid.")
if encrypted_data:
# If INS is even, remove the padding indicator (01)
if do87 is not None:
encrypted_data = encrypted_data[1:]
# Decrypt
if sm_object.enc_alg == "3DES":
decrypted_data = DES3.new(sm_object.ks_enc,
DES3.MODE_CBC,
iv=bytes([0] *
8)).decrypt(encrypted_data)
elif sm_object.enc_alg == "AES":
ssc_enc = AES.new(sm_object.ks_enc,
AES.MODE_ECB).encrypt(sm_object.ssc)
decrypted_data = AES.new(sm_object.ks_enc,
AES.MODE_CBC,
iv=ssc_enc).decrypt(encrypted_data)
# Remove padding
decrypted_data = remove_padding(decrypted_data)
return decrypted_data
def active_auth(dg15: bytes, sm_object: SMObject, security_infos: List[bytes]):
"""
Do active authentication with DG15
"""
# Generate 8 random bytes
rnd_ifd = urandom(8)
# exception caught in main program loop
data = send(
sm_object,
APDU(b"\x00",
b"\x88",
b"\x00",
b"\x00",
Lc=b"\x08",
cdata=rnd_ifd,
Le=b"\x00"))
if data == b"":
raise ActiveAuthenticationError("[-] No reply from card.")
i = asn1_node_root(dg15)
i = asn1_node_first_child(dg15, i)
pub_key = asn1_get_all(dg15, i)
i = asn1_node_first_child(dg15, i)
i = asn1_node_first_child(dg15, i)
if asn1_get_all(dg15, i) == encode_oid_string("1.2.840.10045.2.1"): # ECC
r = data[:len(data) // 2]
s = data[len(data) // 2:]
signature = asn1_sequence(asn1_integer(r) + asn1_integer(s))
ec_pub = EC.pub_key_from_der(pub_key)
if ec_pub.check_key() != 1:
raise ActiveAuthenticationError(
"[-] Active Authentication (AA) failed! Problem in EC Public Key!"
)
try:
hash_type = find_hash_name(security_infos)
except ValueError as ex:
raise ActiveAuthenticationError(
"[-] Active Authentication (AA) failed! Problem in Security Infos hash type!"
) from ex
# for hash_type in ["sha224", "sha256", "sha384", "sha512"]:
try:
result = ec_pub.verify_dsa_asn1(
hashlib.new(hash_type, rnd_ifd).digest(), signature)
except EC.ECError as ex:
print("[-] Error in EC function " + ex)
raise ActiveAuthenticationError(
"[-] Error in verify_dsa_asn1 of M2Crypto.EC") from ex
if result == 1:
print("[+] Active Authentication (AA) completed successfully!")
else:
raise ActiveAuthenticationError(
"[-] Active Authentication (AA) failed!")
elif asn1_get_all(dg15,
i) == encode_oid_string("1.2.840.113549.1.1.1"): # RSA
j = asn1_node_root(pub_key)
j = asn1_node_first_child(pub_key, j)
j = asn1_node_next(pub_key, j)
rsa_pub_key = asn1_get_value_of_type(pub_key, j, "BIT STRING")
if rsa_pub_key[0] != 0x00:
raise ActiveAuthenticationError(
"[-] An issue with the RSA key! Padding 0x00 is expected")
rsa_pub_key = rsa_pub_key[1:]
j = asn1_node_root(rsa_pub_key)
j = asn1_node_first_child(rsa_pub_key, j)
n_der = asn1_get_value_of_type(rsa_pub_key, j, "INTEGER")
j = asn1_node_next(rsa_pub_key, j)
e_der = asn1_get_value_of_type(rsa_pub_key, j, "INTEGER")
n = int.from_bytes(n_der, byteorder="big")
e = int.from_bytes(e_der, byteorder="big")
# rsa_key = RSA.import_key(pub_key)
# https://stackoverflow.com/a/60132608/6077951
msg = int.from_bytes(data, byteorder="big")
dec = pow(msg, e, n).to_bytes(len(data), byteorder="big")
if dec[-1] == 0xCC:
if dec[-2] == 0x38:
hash_alg = "sha224"
elif dec[-2] == 0x34:
hash_alg = "sha256"
elif dec[-2] == 0x36:
hash_alg = "sha384"
elif dec[-2] == 0x35:
hash_alg = "sha512"
t = 2
elif dec[-1] == 0xBC:
hash_alg = "sha1"
t = 1
else:
raise ActiveAuthenticationError(
"[-] Error while Active Authentication!")
def compare_aa(hash_object):
# k = rsa_key.size_in_bits()
# Lh = hash_object.digest_size * 8
# Lm1 = (k - Lh - (8 * t) - 4 - 4) // 8
D = dec[-hash_object.digest_size - t:-t]
M1 = dec[1:-hash_object.digest_size - t]
Mstar = M1 + rnd_ifd
hash_object.update(Mstar)
Dstar = hash_object.digest()
return hmac.compare_digest(D, Dstar)
hash_object = hashlib.new(hash_alg)
if compare_aa(hash_object):
print("[+] Active Authentication (AA) completed successfully!")
else:
raise ActiveAuthenticationError(
"[-] Active Authentication (AA) failed!")
