def accept_session_key(connection, keystore, mode_name='CFB'):
iv = open("iv.txt", 'rb').read(16)
ks = KeyStore(keystore, os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
mode_ = modes_ls[mode_name](iv)
ct = b""
#while True:
chunk = connection.recv(512)
#if not chunk:
#break
ct += chunk
click.echo(
click.style('DEBUG : Decrypting session key with keystore key: %s' %
key,
bold=True,
fg='yellow'))
cipher = Cipher(algorithms.AES(key), mode_, backend=default_backend())
so = SealedObject()
sk = so.unseal(ct, cipher)
click.echo(
click.style('DEBUG : Obtained session key: %s' % sk,
bold=True,
fg='yellow'))
#send private key
connection.sendall(ct)
#click.echo(click.style('Decryption successful!', bold = True, fg = 'green'))
return sk
def accept_session_key(connection, keystore, mode_name='CFB'):
iv = open("iv.txt", 'rb').read(16)
ks = KeyStore(keystore, os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
mode_ = modes_ls[mode_name](iv)
ct = b""
#while True:
chunk = connection.recv(512)
#if not chunk:
#break
ct += chunk
click.echo(click.style('DEBUG : Decrypting session key with keystore key: %s' % key, bold = True, fg = 'yellow'))
cipher = Cipher(algorithms.AES(key), mode_, backend=default_backend())
so = SealedObject()
sk = so.unseal(ct, cipher)
click.echo(click.style('DEBUG : Obtained session key: %s' % sk, bold = True, fg = 'yellow'))
#send private key
connection.sendall(ct)
#click.echo(click.style('Decryption successful!', bold = True, fg = 'green'))
return sk
def accept_session_packet(connection, keystore, mode_name='CFB'):
iv = open("iv.txt", 'rb').read(16)
ks = KeyStore(keystore, os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
ct = b""
#while True:
chunk = connection.recv(512)
#if not chunk:
#break
ct += chunk
so = SealedObject()
packet = so.deserialize(ct)
cipher = ciphers.KeyAES(key, 'CFB8', False, packet.iv)
sk = cipher.decrypt(packet.msg)
#send private key
connection.sendall(ct)
#click.echo(click.style('Decryption successful!', bold = True, fg = 'green'))
return sk
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold = True, fg = 'yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(click.style('Error connecting to server: ' + str(msg[1]), bold = True, fg = 'red'))
ks = KeyStore('enc_key.store', os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
cipher = ciphers.KeyAES(key, 'CFB8', False)
ct = cipher.encrypt(sk)
pkt = packet.Packet(ct, None, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.sendall(csk)
s.recv(512)
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold = True, fg = 'green'))
def negotiate_asymmetric_session_key(connection, private_key, public_key):
pem = public_key.public_bytes(serialization.Encoding.PEM, serialization.PublicFormat.SubjectPublicKeyInfo)
#send public key over network
connection.sendall(pem)
#accept session key
csk = connection.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
return sk
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold = True, fg = 'yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(click.style('Error connecting to server: ' + str(msg[1]), bold = True, fg = 'red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
pem = s.recv(2048)
#click.echo(click.style('Client: public key = %s' % rsa_public_key, bold = True, fg = 'green'))
rsa_public_key = serialization.load_pem_public_key(pem, backend=default_backend())
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
so = SealedObject()
csk = so.seal_asym(sk, rsa_public_key)
s.sendall(csk)
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold = True, fg = 'green'))
def negotiate_asymmetric_session_key(connection, private_key, public_key):
pem = public_key.public_bytes(
serialization.Encoding.PEM,
serialization.PublicFormat.SubjectPublicKeyInfo)
#send public key over network
connection.sendall(pem)
#accept session key
csk = connection.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
return sk
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold=True, fg='yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(
click.style('Error connecting to server: ' + str(msg[1]),
bold=True,
fg='red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
ks = KeyStore('enc_key.store', os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
sk = os.urandom(16)
so = SealedObject()
cipher = Cipher(algorithms.AES(key),
mode=modes.CFB8(open('iv.txt', 'rb').read(16)),
backend=default_backend())
csk = so.seal(sk, cipher)
s.sendall(csk)
#time.sleep(1)
s.recv(512)
cipher = Cipher(algorithms.AES(sk),
mode=modes.CFB8(open('iv.txt', 'rb').read(16)),
backend=default_backend())
encryptor = cipher.encryptor()
ct = encryptor.update(pt) + encryptor.finalize()
s.send(ct)
s.close()
click.echo(click.style('File sent!', bold=True, fg='green'))
def negotiate_asymmetric_session_key(connection, private_key, public_key, signature):
pem = public_key
#send public key and signature over network
#create packet husk
pkt = packet.Packet(pem, None, None)
pkt.add_attribute(signature, id='sig')
so = SealedObject()
csig = so.serialize(pkt)
connection.sendall(csig)
#accept session key
csk = connection.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
return sk
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold = True, fg = 'yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(click.style('Error connecting to server: ' + str(msg[1]), bold = True, fg = 'red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
ks = KeyStore('enc_key.store', os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
sk = os.urandom(16)
so = SealedObject()
cipher = Cipher(algorithms.AES(key), mode=modes.CFB8(open('iv.txt', 'rb').read(16)), backend=default_backend())
csk = so.seal(sk, cipher)
s.sendall(csk)
#time.sleep(1)
s.recv(512)
cipher = Cipher(algorithms.AES(sk), mode=modes.CFB8(open('iv.txt', 'rb').read(16)), backend=default_backend())
encryptor = cipher.encryptor()
ct = encryptor.update(pt) + encryptor.finalize()
s.send(ct)
s.close()
click.echo(click.style('File sent!', bold = True, fg = 'green'))
def decrypt_AES_with_key_mac(connection, outfile, s_key, hmac):
ct = b""
while True:
chunk = connection.recv(50)
if not chunk:
break
ct += chunk
so = SealedObject()
packet = so.deserialize(ct)
#verify mac
if not hmac.verMAC(packet.msg, 0, packet.mac):
#reject
click.echo(click.style('Decryptionphailed', bold = True, fg = 'red'))
else:
cipher = ciphers.KeyAES(s_key, 'CFB8', False, packet.iv)
dt = cipher.decrypt(packet.msg)
outfile.write(dt)
click.echo(click.style('Decryption successful!', bold = True, fg = 'green'))
def decrypt_AES_with_key_mac(connection, outfile, s_key, hmac, mode_name='CFB8'):
ct = b""
while True:
chunk = connection.recv(50)
if not chunk:
break
ct += chunk
so = SealedObject()
packet = so.deserialize(ct)
#verify mac
if not hmac.verMAC(packet.msg, packet.mac):
#reject
click.echo(click.style('Decryptionphailed', bold = True, fg = 'red'))
else:
cipher = ciphers.KeyAES(s_key, 'CFB8', False, packet.iv)
dt = cipher.decrypt(packet.msg)
outfile.write(dt)
click.echo(click.style('Decryption successful!', bold = True, fg = 'green'))
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold=True, fg='yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(
click.style('Error connecting to server: ' + str(msg[1]),
bold=True,
fg='red'))
ks = KeyStore('enc_key.store', os.path.abspath(''))
key = str.encode(ks.keys['mother_base_key'].public_key)
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
cipher = ciphers.KeyAES(key, 'CFB8', False)
ct = cipher.encrypt(sk)
pkt = packet.Packet(ct, None, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.sendall(csk)
s.recv(512)
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold=True, fg='green'))
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold=True, fg='yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(
click.style('Error connecting to server: ' + str(msg[1]),
bold=True,
fg='red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
pem = s.recv(2048)
#click.echo(click.style('Client: public key = %s' % rsa_public_key, bold = True, fg = 'green'))
rsa_public_key = serialization.load_pem_public_key(
pem, backend=default_backend())
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
so = SealedObject()
csk = so.seal_asym(sk, rsa_public_key)
s.sendall(csk)
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold=True, fg='green'))
def negotiate_asymmetric_session_key(connection, private_key, public_key,
signature):
pem = public_key
#send public key and signature over network
#create packet husk
pkt = packet.Packet(pem, None, None)
pkt.add_attribute(signature, id='sig')
so = SealedObject()
csig = so.serialize(pkt)
connection.sendall(csig)
#accept session key
csk = connection.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
return sk
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold = True, fg = 'yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(click.style('Error connecting to server: ' + str(msg[1]), bold = True, fg = 'red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
in_cert = s.recv(2048)
# Validate server certificate using CA certificate
server_cert = x509.load_der_x509_certificate(in_cert, default_backend())
ca_cert_file = open('ca.cer', 'rb')
ca_cert = ca_cert_file.read()
ca_cert_file.close()
store = crypto.X509Store()
store.add_cert(crypto.load_certificate(crypto.FILETYPE_ASN1, ca_cert))
store_ctx = crypto.X509StoreContext(store, server_cert)
if store_ctx.verify_certificate() != None:
click.echo(click.style('Error validating server certificate', bold = True, fg = 'red'))
return
else:
click.echo(click.style('Valid server certificate!', bold = True, fg = 'green'))
server_public_key = server_cert.public_key()
client_cert_file = open('client.cer', 'rb')
client_cert = client_cert_file.read()
client_cert_file.close()
s.send(client_cert)
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
so = SealedObject()
csk = so.seal_asym(sk, server_public_key)
s.sendall(csk)
challenge = s.recv(32)
private_key_file = open('client.pk8', 'rb')
private_key = private_key_file.read()
private_key_file.close()
private_key = load_der_private_key(private_key, password=None, backend=default_backend())
signer = private_key.signer(padding.PSS(mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
signer.update(challenge)
signature = signer.finalize()
s.send(signature)
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold = True, fg = 'green'))
def server(folder):
HOST = ''
PORT = 4567
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#Create server socket
try:
s.bind((HOST, PORT))
except socket.error as msg:
print('Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1])
sys.exit()
#Start listening on socket
s.listen(10)
print('Server started ...')
#Start upload counter
counter = 0;
#now keep talking with the client
while 1:
#wait for client - conn is input stream
conn, addr = s.accept()
#Increment counter
counter += 1
print("Accepted connection " + str(counter) + ".");
# Load and send server certificate
server_cert_file = open('server.cer', 'rb')
server_cert = server_cert_file.read()
server_cert_file.close()
conn.send(bytes(server_cert))
in_cert = conn.recv(2048)
# Validate server certificate using CA certificate
client_cert = x509.load_der_x509_certificate(in_cert, default_backend())
ca_cert_file = open('ca.cer', 'rb')
ca_cert = ca_cert_file.read()
ca_cert_file.close()
store = crypto.X509Store()
store.add_cert(crypto.load_certificate(crypto.FILETYPE_ASN1, ca_cert))
store_ctx = crypto.X509StoreContext(store, client_cert)
if store_ctx.verify_certificate() != None:
click.echo(click.style('Error validating client certificate', bold = True, fg = 'red'))
return
else:
click.echo(click.style('Valid client certificate!', bold = True, fg = 'green'))
client_public_key = client_cert.public_key()
private_key_file = open('server.pk8', 'rb')
private_key = private_key_file.read()
private_key_file.close()
private_key = load_der_private_key(private_key, password=None, backend=default_backend())
#accept session key
csk = conn.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
challenge = os.urandom(32)
conn.send(challenge)
signature = conn.recv(512)
verifier = client_public_key.verifier(signature, padding.PSS(mgf=padding.MGF1(hashes.SHA256()), salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
verifier.update(challenge)
try:
verifier.verify()
except InvalidKey:
click.echo(click.style('Error verifying signature!', bold = True, fg = 'red'))
return
#Open file to write to
f = open(folder + "/" + str(counter), 'wb')
sess_k = sk[0:16]
mac_k = sk[16:32]
hmac = mac.MAC(mac_k)
crypt.decrypt_AES_with_key_mac(conn, f, sess_k, hmac)
f.close()
print("Closed connection.")
s.close()
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold=True, fg='yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(
click.style('Error connecting to server: ' + str(msg[1]),
bold=True,
fg='red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
r_pkt = s.recv(2048)
#click.echo(click.style('Client: public key = %s' % rsa_public_key, bold = True, fg = 'green'))
so = SealedObject()
pkt = so.deserialize(r_pkt)
signature = pkt.get_attribute('sig')
pem = pkt.msg
rsa_public_key = serialization.load_pem_public_key(
pem.encode(), backend=default_backend()
) #.public_bytes(serialization.Encoding.PEM, serialization.PublicFormat.SubjectPublicKeyInfo)
key_bytes = rsa_public_key.public_bytes(
serialization.Encoding.PEM,
serialization.PublicFormat.SubjectPublicKeyInfo)
verifier = rsa_public_key.verifier(
signature,
padding.PSS(mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
verifier.update(key_bytes)
try:
verifier.verify()
except InvalidKey:
click.echo(click.style('Error verifying key', bold=True, fg='red'))
return
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
so = SealedObject()
csk = so.seal_asym(sk, rsa_public_key)
s.sendall(csk)
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold=True, fg='green'))
def server(folder):
HOST = ''
PORT = 4567
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#Create server socket
try:
s.bind((HOST, PORT))
except socket.error as msg:
print('Bind failed. Error Code : ' + str(msg[0]) + ' Message ' +
msg[1])
sys.exit()
#Start listening on socket
s.listen(10)
print('Server started ...')
#Start upload counter
counter = 0
#now keep talking with the client
while 1:
#wait for client - conn is input stream
conn, addr = s.accept()
#Increment counter
counter += 1
print("Accepted connection " + str(counter) + ".")
# Load and send server certificate
server_cert_file = open('server.cer', 'rb')
server_cert = server_cert_file.read()
server_cert_file.close()
conn.send(bytes(server_cert))
in_cert = conn.recv(2048)
# Validate server certificate using CA certificate
client_cert = x509.load_der_x509_certificate(in_cert,
default_backend())
ca_cert_file = open('ca.cer', 'rb')
ca_cert = ca_cert_file.read()
ca_cert_file.close()
store = crypto.X509Store()
store.add_cert(crypto.load_certificate(crypto.FILETYPE_ASN1, ca_cert))
store_ctx = crypto.X509StoreContext(store, client_cert)
if store_ctx.verify_certificate() != None:
click.echo(
click.style('Error validating client certificate',
bold=True,
fg='red'))
return
else:
click.echo(
click.style('Valid client certificate!', bold=True,
fg='green'))
client_public_key = client_cert.public_key()
private_key_file = open('server.pk8', 'rb')
private_key = private_key_file.read()
private_key_file.close()
private_key = load_der_private_key(private_key,
password=None,
backend=default_backend())
#accept session key
csk = conn.recv(512)
#unseal session key
so = SealedObject()
sk = so.unseal_asym(csk, private_key)
challenge = os.urandom(32)
conn.send(challenge)
signature = conn.recv(512)
verifier = client_public_key.verifier(
signature,
padding.PSS(mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
verifier.update(challenge)
try:
verifier.verify()
except InvalidKey:
click.echo(
click.style('Error verifying signature!', bold=True, fg='red'))
return
#Open file to write to
f = open(folder + "/" + str(counter), 'wb')
sess_k = sk[0:16]
mac_k = sk[16:32]
hmac = mac.MAC(mac_k)
crypt.decrypt_AES_with_key_mac(conn, f, sess_k, hmac)
f.close()
print("Closed connection.")
s.close()
def cli(filename):
"""Send file over to server"""
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '127.0.0.1'
port = 4567
click.echo(click.style('Connecting...', bold=True, fg='yellow'))
try:
s.connect((host, port))
except socket.error as msg:
click.echo(
click.style('Error connecting to server: ' + str(msg[1]),
bold=True,
fg='red'))
pt = b""
while True:
chunk = filename.read(100)
if not chunk:
break
pt += chunk
in_cert = s.recv(2048)
# Validate server certificate using CA certificate
server_cert = x509.load_der_x509_certificate(in_cert, default_backend())
ca_cert_file = open('ca.cer', 'rb')
ca_cert = ca_cert_file.read()
ca_cert_file.close()
store = crypto.X509Store()
store.add_cert(crypto.load_certificate(crypto.FILETYPE_ASN1, ca_cert))
store_ctx = crypto.X509StoreContext(store, server_cert)
if store_ctx.verify_certificate() != None:
click.echo(
click.style('Error validating server certificate',
bold=True,
fg='red'))
return
else:
click.echo(
click.style('Valid server certificate!', bold=True, fg='green'))
server_public_key = server_cert.public_key()
client_cert_file = open('client.cer', 'rb')
client_cert = client_cert_file.read()
client_cert_file.close()
s.send(client_cert)
sk = os.urandom(32)
sk1 = sk[0:16]
sk2 = sk[16:32]
so = SealedObject()
csk = so.seal_asym(sk, server_public_key)
s.sendall(csk)
challenge = s.recv(32)
private_key_file = open('client.pk8', 'rb')
private_key = private_key_file.read()
private_key_file.close()
private_key = load_der_private_key(private_key,
password=None,
backend=default_backend())
signer = private_key.signer(
padding.PSS(mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH), hashes.SHA256())
signer.update(challenge)
signature = signer.finalize()
s.send(signature)
cipher = ciphers.KeyAES(sk1, 'CFB8', False)
ct = cipher.encrypt(pt)
hmac = mac.MAC(sk2)
mac1 = hmac.genMAC(ct, 0)
pkt = packet.Packet(ct, mac1, cipher.iv)
so = SealedObject()
csk = so.serialize(pkt)
s.send(csk)
s.close()
click.echo(click.style('File sent!', bold=True, fg='green'))