print("".center(80,"*"))

print("Decrypting data...")

t=""

#packetReceived=packetReceived.lower()

if key!=None and key!="":

for i in packetReceived:

if i.isupper():

alphabet = chr((ord(i)-int(key)-65)%26+65)

elif i.islower():

alphabet = chr((ord(i)-int(key)-97)%26+97)

else:

alphabet = chr(ord(i)-int(key))

t=t+alphabet

#message

print("Data successfully decrypted")

print("The data send by the sender is :",t)

print("The data packet is decrypted successfully with the secret key\

\n\nCONFIDENTIALITY goal is achieved.........")

else:

print("Key not received. Modified during transmission")

print("The data packet cannot be decrypted as correct secret key not received\

\n\nCONFIDENTIALITY goal is not achieved.........")

print("".center(80,"*"))

if received:

print("Computing the hash of the data...")

hashedData = hashlib.md5(message.encode())

hashedDataByte = hashedData.hexdigest()

print("Hash computed: ",hashedDataByte,"\nHash value received: ",hashValue)

if hashedDataByte == hashValue:

print("The data packet is not modified i.e. the data has not lost its integrity\

\n\nINTEGRITY goal is achieved.........")

else:

print("The data packet is modified i.e. the data has lost its integrity\

\n\nINTEGRITY goal is not achieved.........")

else:

print("The data packet cannot be decrypted as key is not received. Cannot check integrity of data\

print("".center(80,"*"))

if received:

print("The data packet is received by the receiver successfully i.e. the data is available to the user\

\n\nAVAILBILITY goal is achieved.........")

else:

print("The data packet is can't be decrypted hence the data is not available\

packetReceived = ast.literal_eval(message)

#packetReceived = message.split("-")

print("The Received Packet is : ",packetReceived)

print("The message received from the Sender is : ",packetReceived['Message'])

decryptedData = check_confidentiality(packetReceived['Message'],packetReceived['Key'])

if decryptedData=="":

check_availbility(packetReceived['Message'],received=False)

check_integrity(decryptedData,packetReceived['Hash'],received=False)

else:

check_availbility(packetReceived['Message'])

sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM)

#Get Local machine name

host = socket.gethostname()

port = 9999

#connection to the hostname on the port

sock.connect((host,port))

sock.settimeout(5)

#receive no more than 1024 bytes

try:

#normal packet case

message = sock.recv(1024)

message = message.decode('ascii')

print("Received data.........\nChecking whether data satisfies the three security goals 'CIA' \

Confidentiality,Integrity,Availbility\n")

print(message)

callFunctions(message)

#key modified case

message = sock.recv(1024)

message = message.decode('ascii')

print("Received data.........\nChecking whether data satisfies the three security goals 'CIA' \

Confidentiality,Integrity,Availbility\n")

print(message)

callFunctions(message)

#connection closed case - no packet received

message = sock.recv(1024)

message = message.decode('ascii')

print("Received data.........\nChecking whether data satisfies the three security goals 'CIA' \

Confidentiality,Integrity,Availbility\n")

print(message)

callFunctions(message)

except Exception:

print("No Packet received from the sender, CIA Triad not satisified.")

finally:

print("Closing connection")

sock.close()