CS419 - Computer Security | Spring 2022

Assignment 1 - Access Control

The goal of this project is to simulate access control mechanisms with things like:

• Users
• Domains
• Types
• Access Permissions

Assignment 2 - Rootkit

Part 1: Hiding Files

The first part of this project involves hiding files from a user when calling 'ls'. This is done by simulating the functionality of readdir, but when given a filename that we should hide we are not to return it to the user. File names to hide are put under a environment variable called "HIDDEN".

Part 2: Changing Time

Similarly to part 1, this part involves overwriting the libc "time" function. On first run of the program we are to lie to any program about the current time, and any subsequent call should return the true time.

Assignment 3 - Encryption

Part 1: Binary Vigenere Cipher

The first part of this project involves implementing a very simple cipher based on the vigenere cipher:
ciphertext[i] = (plaintext[i] + key[i % len(key)]) % len(alphabet)

Part 2: Stream cipher

Part 2 of this project requires implementing a keystream and using it in order to encrypt plaintext.

Part 3: Block Encryption with Cipher Block Chaining and Padding

The final part builds off of part 2. It uses a combination of stream cipher and encrypting in blocks in order to create a stronger cipher.

Notes

For a more detailed explanation of the project check 'project3.pdf' under 'project3'.

Assignment 4 - Proof-of-Work

Part 1: Proof-of-Work Generator

The first part of this project requires building a proof-of-work generator. For any given set of text, the program should be able to compute a hash that builds a string with a ceratin amount of leading zeros in front of the original hash.

Part 2: Proof-of-Work Validator

The second part of this project requires building a validator for any proof-of-work generated. Whether it be the generated material from part 1, or any given test cases.