def encode_msg(self, msg):
"""Apply security layer and return encode MSG in Json
:param msg: xAAL msg instance
:type msg: Message
:return: return an xAAL msg ciphered and serialized in json
:rtype: json
"""
result = {}
# Format data msg to send
result['version'] = msg.version
result['targets'] = json.dumps(msg.targets)
result['timestamp'] = msg.timestamp
# Format payload before ciphering
if msg.body:
buf = json.dumps({"header": msg.header, "body": msg.body})
else:
buf = json.dumps({"header": msg.header})
# Payload Ciphering: ciph
# Additionnal Data == json serialization of the targets array
payload = buf.encode('utf-8')
ad = json.dumps(msg.targets).encode('utf-8') # Additional Data
nonce = build_nonce(msg.timestamp)
ciph = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(
payload, ad, nonce, self.cipher_key)
# Add payload: base64 encoded of payload cipher
result['payload'] = base64.b64encode(ciph)
# Json serialization
return json.dumps(result)
def constructSTSResponse(self, mType, addr, exchangeData):
data = None
addrStr = sts_utility.addrToString(addr)
if addrStr in STS.STSConnectionStates.keys():
if STS.STSConnectionStates[addrStr][
'cSuite'] == 1 or STS.STSConnectionStates[addrStr][
'cSuite'] == 4:
nonce = pysodium.randombytes(
pysodium.crypto_aead_chacha20poly1305_ietf_NONCEBYTES)
m = struct.pack('>B', mType) + struct.pack('>I', len(nonce))
# T = struct.pack('>Q', int(time.time()))
encrypData = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(
exchangeData, m, nonce,
STS.STSConnectionStates[addrStr]['session_key'][:32])
data = m + nonce + encrypData
elif STS.STSConnectionStates[addrStr][
'cSuite'] == 2 or STS.STSConnectionStates[addrStr][
'cSuite'] == 5:
nonce = pysodium.randombytes(
pysodium.crypto_aead_chacha20poly1305_NONCEBYTES)
m = struct.pack('>B', mType) + struct.pack('>I', len(nonce))
# T = struct.pack('>Q', int(time.time()))
encrypData = pysodium.crypto_aead_chacha20poly1305_encrypt(
exchangeData, m, nonce,
STS.STSConnectionStates[addrStr]['session_key'][:32])
data = m + nonce + encrypData
# print(binascii.hexlify(T))
# print(binascii.hexlify(pysodium.crypto_aead_chacha20poly1305_ietf_decrypt(encrypData, m, nonce, myTX[:32])))
return data
def test_aead_chacha20poly1305_ietf(self):
if not pysodium.sodium_version_check(1, 0, 4): return
key = binascii.unhexlify(b"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd1100a1007")
input_ = binascii.unhexlify(b"86d09974840bded2a5ca")
nonce = binascii.unhexlify(b"cd7cf67be39c794a")
ad = binascii.unhexlify(b"87e229d4500845a079c0")
output = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(input_, ad, nonce, key)
output = pysodium.crypto_aead_chacha20poly1305_ietf_decrypt(output, ad, nonce, key)
self.assertEqual(output, input_)
def test_aead_chacha20poly1305_ietf(self):
if not pysodium.sodium_version_check(1, 0, 4): return
key = binascii.unhexlify(b"4290bcb154173531f314af57f3be3b5006da371ece272afa1b5dbdd1100a1007")
input_ = binascii.unhexlify(b"86d09974840bded2a5ca")
nonce = binascii.unhexlify(b"cd7cf67be39c794acd7cf67b")
for ad in [binascii.unhexlify(b"87e229d4500845a079c0"), None]:
output = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(input_, ad, nonce, key)
output = pysodium.crypto_aead_chacha20poly1305_ietf_decrypt(output, ad, nonce, key)
self.assertEqual(output, input_)
def test(msg, aad, nonce, key):
ct = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(
msg, aad, nonce, key)
ct, tag = ct[:len(msg)], ct[len(msg):]
print """
vector("%s",
"%s",
"%s",
"%s",
"%s",
"%s");""" % (key.encode('hex'), nonce.encode('hex'),
aad.encode('hex'), msg.encode('hex'), ct.encode('hex'),
tag.encode('hex'))
def encrypt_plaintext(message: str, add_data: bytes,
key: bytes) -> (bytes, bytes, bytes):
"""
Encrypt the payload of a packed message.
Args:
message: Message to encrypt
add_data:
key: Key used for encryption
Returns:
A tuple of (ciphertext, nonce, tag)
"""
nonce = pysodium.randombytes(
pysodium.crypto_aead_chacha20poly1305_ietf_NPUBBYTES)
message_bin = message.encode("ascii")
output = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(
message_bin, add_data, nonce, key)
mlen = len(message)
ciphertext = output[:mlen]
tag = output[mlen:]
return ciphertext, nonce, tag
# generate a random 64 bit
nonce = pysodium.randombytes(
pysodium.crypto_aead_chacha20poly1305_ietf_NPUBBYTES)
assert pysodium.crypto_aead_chacha20poly1305_ietf_NPUBBYTES == 12
# write additional data into a single DER structure
encoder = asn1.Encoder()
encoder.start()
encoder.enter(asn1.Numbers.Sequence)
encoder.write(enckey, asn1.Numbers.OctetString)
encoder.write(nonce, asn1.Numbers.OctetString)
encoder.write(clargs.interval, asn1.Numbers.Integer)
encoder.leave()
AD = encoder.output()
ctext = pysodium.crypto_aead_chacha20poly1305_ietf_encrypt(
message=message.encode(), ad=AD, nonce=nonce, key=chachakey)
# encode the whole contents, AD + ctext
encoder = asn1.Encoder()
encoder.start()
encoder.enter(asn1.Numbers.Sequence)
encoder.enter(asn1.Numbers.Sequence)
encoder.write(enckey, asn1.Numbers.OctetString)
encoder.write(nonce, asn1.Numbers.OctetString)
encoder.write(clargs.interval, asn1.Numbers.Integer)
encoder.leave()
encoder.write(ctext, asn1.Numbers.OctetString)
encoder.leave()
DERmsg = encoder.output()
print('-----BEGIN CHK ENCRYPTED MESSAGE-----')
