def external_authenticate(self, p1, p2, resp_data):
"""Performs the basic access control protocol as defined in
the ICAO MRTD standard"""
rnd_icc = self.last_challenge
# Receive Mutual Authenticate APDU from terminal
# Decrypt data and check MAC
Eifd = resp_data[:-8]
padded_Eifd = vsCrypto.append_padding(self.current_SE.cct.blocklength,
Eifd)
Mifd = vsCrypto.crypto_checksum("CC", self.KMac, padded_Eifd)
# Check the MAC
if not Mifd == resp_data[-8:]:
raise SwError(SW["ERR_SECMESSOBJECTSINCORRECT"])
# Decrypt the data
plain = vsCrypto.decrypt("DES3-CBC", self.KEnc, resp_data[:-8])
if plain[8:16] != rnd_icc:
raise SwError(SW["WARN_NOINFO63"])
# Extract keying material from IFD, generate ICC keying material
Kifd = plain[16:]
rnd_ifd = plain[:8]
Kicc = urandom(16)
# Generate Answer
data = plain[8:16] + plain[:8] + Kicc
Eicc = vsCrypto.encrypt("DES3-CBC", self.KEnc, data)
padded_Eicc = vsCrypto.append_padding(self.current_SE.cct.blocklength,
Eicc)
Micc = vsCrypto.crypto_checksum("CC", self.KMac, padded_Eicc)
# Derive the final keys and set the current SE
KSseed = vsCrypto.operation_on_string(Kicc, Kifd, lambda a, b: a ^ b)
self.current_SE.ct.key = self.derive_key(KSseed, 1)
self.current_SE.cct.key = self.derive_key(KSseed, 2)
self.current_SE.ssc = stringtoint(rnd_icc[-4:] + rnd_ifd[-4:])
return SW["NORMAL"], Eicc + Micc
def verify_cryptographic_checksum(self, p1, p2, data):
"""
Verify the cryptographic checksum contained in the data field.
Data field must contain a cryptographic checksum (tag 0x8E) and a plain
value (tag 0x80)
"""
plain = ""
cct = ""
algo = self.cct.algorithm
key = self.cct.key
iv = self.cct.iv
if algo == None or key == None:
raise SwError(SW["ERR_CONDITIONNOTSATISFIED"])
structure = unpack(data)
for tag, length, value in structure:
if tag == 0x80:
plain = value
elif tag == 0x8E:
cct = value
if plain == "" or cct == "":
raise SwError(SW["ERR_SECMESSOBJECTSMISSING"])
else:
my_cct = vsCrypto.crypto_checksum(algo, key, plain, iv)
if my_cct == cct:
return ""
else:
raise SwError["ERR_SECMESSOBJECTSINCORRECT"]
def verify_cryptographic_checksum(self, p1, p2, data):
"""
Verify the cryptographic checksum contained in the data field.
Data field must contain a cryptographic checksum (tag 0x8E) and a plain
value (tag 0x80)
"""
plain = ""
cct = ""
algo = self.cct.algorithm
key = self.cct.key
iv = self.cct.iv
if algo == None or key == None:
raise SwError(SW["ERR_CONDITIONNOTSATISFIED"])
structure = unpack(data)
for tag, length, value in structure:
if tag == 0x80:
plain = value
elif tag == 0x8E:
cct = value
if plain == "" or cct == "":
raise SwError(SW["ERR_SECMESSOBJECTSMISSING"])
else:
my_cct = vsCrypto.crypto_checksum(algo, key, plain, iv)
if my_cct == cct:
return ""
else:
raise SwError["ERR_SECMESSOBJECTSINCORRECT"]
def compute_cryptographic_checksum(self, p1, p2, data):
"""
Compute a cryptographic checksum (e.g. MAC) for the given data.
Algorithm and key are specified in the current SE
"""
if p1 != 0x8E or p2 != 0x80:
raise SwError(SW["ERR_INCORRECTP1P2"])
if self.cct.key is None:
raise SwError(SW["ERR_CONDITIONNOTSATISFIED"])
checksum = vsCrypto.crypto_checksum(self.cct.algorithm, self.cct.key, data, self.cct.iv)
return checksum
def compute_cryptographic_checksum(self, p1, p2, data):
"""
Compute a cryptographic checksum (e.g. MAC) for the given data.
Algorithm and key are specified in the current SE
"""
if p1 != 0x8E or p2 != 0x80:
raise SwError(SW["ERR_INCORRECTP1P2"])
if self.cct.key == None:
raise SwError(SW["ERR_CONDITIONNOTSATISFIED"])
checksum = vsCrypto.crypto_checksum(self.cct.algorithm, self.cct.key,
data, self.cct.iv)
return checksum
def compute_cryptographic_checksum(self, p1, p2, data):
"""
Compute a cryptographic checksum (e.g. MAC) for the given data.
The ePass uses a Send Sequence Counter for MAC calculation
"""
if p1 != 0x8E or p2 != 0x80:
raise SwError(SW["ERR_INCORRECTP1P2"])
self.ssc += 1
checksum = vsCrypto.crypto_checksum(self.cct.algorithm, self.cct.key,
data, self.cct.iv, self.ssc)
return checksum
