代写CSCI368/CSCI968 - (Advanced) Network Security Spring 2024 Assignment 1代做C/C++程序

CSCI368/CSCI968 - (Advanced) Network Security

Spring 2024

Assignment 1 (10 Marks, Weight 15%)

Submission Due: 21 Aug 2024 23:30

Objective

On completion of this assignment, you should be able to use some basic cryptographic techniques to secure remote communications.

Programing Task

Write (Java/C++/Python) UDP programs to allow two parties to perform authentication and establish a secure communication channel. For simplicity, let us call the programs “Host” and “Client”, which are executed by Alice and Bob, respectively.

Alice and Bob share a common password PW, which contains 8 alphanumeric characters. Alice also has a public and privacy key pair (pk, sk) for the RSA encryption scheme. They want to establish a secure communication channel that can provide data confidentiality and integrity. This will be done via the following steps: (1) perform an authentication and key establishment protocol to establish a fresh secret key; and (2) use the established secret key to secure the real communication.

Step 1 is done via the following authentication and key establishment protocol:

1:    B → A: Bob, NB

2:    A → B: Alice, pk, NA

3:    B → A: C1 = PKE pk(PW, K)

Alice decrypts C1 using sk to get PW and K, and then verifies PW. Alice sends either “Connection Okay” or “Connection Failed” to Bob to indicate whether the connection is successful or not.

4:   A → B: Connection Okay/Failed

In the above protocol, NB and NA denote two 128-bit random strings chosen by Bob and Alice, respectively, and PKE denotes the RSA encryption. K is a 128-bit random secret key selected by Bob. Alice and Bob then compute the shared secret key as ssk = H(K,NB,NA) where H denotes the  SHA-1 hash algorithm.

After establishing the secret session key, step 2 is done as follows:

1.   whenever Alice wants to send a message m to Bob, Alice first computes an integrity check value h = H(ssk, m), and then computes C = SKEssk(m||h) and sends C to Bob;

2.   upon receiving a ciphertext C, Bob first runs the decryption algorithm to obtain m||h. After that, Bob computes h ’ = H(ssk, m) and checks if h = h ’. If the equation holds, then Bob accepts m; otherwise, Bob rejects the ciphertext;

3.   the same operations are performed when Bob sends a message to Alice.

The SKE in step 2 denotes the RC4 stream cipher.

Implementation guidelines

•    Place Host and Client in two separate directories: Alice and Bob. Alice also stores a password file in her directory. The password file contains all the user records, e.g., (Bob, H(PW)).

•    Generate a public and private key pair for Alice, and store the generated public and private key  pair in a key file under Alice’s directory. Store the fingerprint of Alice’spublic key (i.e., H(pk)) in Bob’s directory. This step is done using a separate key_setup program.

•    Alice executes Host.

-    Host is running and listening to the opened port (you need to  select a port (e.g., 5555) for Host).

•    Bob executes Client that uses a different port number (e.g., 3333).

-    Client asks for input (username and PW) from Bob via keyboard.

-    Client sends the first message in the authentication protocol to Host.

-    Upon receiving the second message from Host, Client checks if the received pk matches the stored fingerprint of the Host. If they don’t match, Client terminates the  connection; otherwise, carry on.

•    Alice and Bob complete the authentication and key establishment protocol.

•    If Alice cannot successfully authenticate Bob, then Alice sends “Connection Failed” to Bob and wait for a new connection. Bob quits the program after receiving the message from Alice.

•    If the connection is successfully established,

-    Either Alice or Bob can send a message encrypted and authenticated by the session key ssk. They type the message on their own terminal. The message is processed by their code according to step 2 given above.

-    A received message is printed on the screen  if decryption is  successful. Otherwise, print “Decryption Error” on the screen.

-    To close the connection, Bob should type “exit” .

You can choose to use existing libraries or open source code to implement UDP sockets, RSA, RC4 and SHA-1. You should provide a reference if you use any downloaded code.

How to run?

Your programs should run according to the protocol. Host and Client should be executed on two different terminals. For convenience of marking, please use the local IP: 127.0.0.1 for the submitted version. For simplicity, there is no GUI required in this assignment. That is, messages are simply typed on one terminal and printed on the receiver’sterminal.

Mark distribution:

1.   RSA key generation and storage: 1 mark

2.   Authentication and Key Establishment (Step 1): 4 marks

3.   Data Encryption/Decryption (Step 2): 4 marks

4.   Proper and clear message display: 1 mark

Note: code that cannot be compiled or executed will receive a zero mark.

Files to be submitted:

All source codes (Do not submit any executable).

A readme file (text/ACSII only): instructions about how to compile and run your code.

Submission

Compress all the files to be submitted into a zip file and submit it via the submission link provided in the Moodle site.

Late Submission: Penalty is 25% deduction per day (including weekends) unless Academic Consideration is granted.

Plagiarism

A plagiarised assignment will receive a zero mark and be penalised according to the university rules. Plagiarism detection software will be used.