RSA-AES-verification

The project uses Simple AES for encryption and decryption, RSA algorithm for digital signature verification.

HOW TO RUN THE CODE

• Step 1 : run server.py file using "python server.py"
• Step 2 : run client.py file using "python client.py"
• aes_en.py contains the code to encrypt the plaintext using simple AES algorithm as given.
• aes_de.py contains the code to decrypt the ciphertext using simple AES algorithm as given.
• client.py contains socket code for client side.
• server.py contains socket code for server side.
• rsa.py contains the functions for RSA algorithm and converting the text to digest.
• All the functions used are having names as per their uses.

THEORY

Block diagram for Simple AES used here.

Block diagram for the project.

NOTE

1. The Plaintext and cipher key should be Integer.
   
2. The Public and private key parameters (p and q) should be distinct prime numbers for both server and client.
   
3. For a secure RSA Implementation, p and q should be selected greater than 100.
   
4. server.py should be run before client.py.
   

Project Workflow

• Client inputs: Message, Secret Key, Public and Private key parameters for Client
• Server Inputs: Public and Private key parameters for Server.

Message Flow:

• Client requests for public key of server.
• Server sends the public key.
• Client sends Ciphertext, Encrypted secret key, Client Signature, Client public key.

Client side computation:

• Create Client signature through RSA algorithm, taking Digest from Hash algorithm and client private key as input.
• Create Ciphertext through the AES variant, taking Message and Secret key as input.
• Encrypt Secret key with RSA algorithm, taking Secret key and Server Public key as input.

Server side Computation:

• Decrypt Secret key using RSA algorithm
• Decrypt ciphertext using AES variant
• Create message digest
• Verify Client Signature

OUTPUT