niharvnit-cmd/Cybersecurity_Summer_Project — reverse-engineered prompt

Build me a simple Python cybersecurity class project that demonstrates hashing and the avalanche effect. I want it to run from the command line, ask the user for an input string, hash it with SHA 256, make a very small random change to the input, hash it again, then show how many bits changed and the percentage difference.

Also make a similar part using keccak256. Include a small script that verifies the known keccak256 hash of an empty string by hashing an empty string and comparing the result.

Please make the code easy for a beginner to understand, with clear comments explaining almost every step. Save or print the results clearly so I can show them as challenge output. Add a README that explains the approach in simple words and includes short answers about the avalanche effect, why using only a block timestamp is not unique enough, and why rotating a salt makes old QR or hash values invalid.