This repository contains my solutions for the MC103 – Cryptography and Blockchain exam at Kristiania University (February 2025).
The work demonstrates applied skills in cryptography, blockchain analysis, Ethereum smart contract development, and decentralized storage (IPFS).
- Broke Caesar and substitution ciphers using brute-force search and Python scripts
- Identified transposition vs. substitution ciphers with systematic testing
- Generated and verified digests with SHA-1, SHA-256, MD5, RIPEMD-160
- Analyzed hash lengths, collisions, and security properties
- Inspected and verified PGP keys (RSA & Ed25519)
- Used SSH keys for authentication and Git commits without passwords
- Encrypted, signed, and verified emails/messages with PGP
- Analyzed Bitcoin transactions, blocks, addresses, and Silk Road seizure wallet
- Investigated Ethereum contracts, owners, and functionality
- Explored special edge cases (e.g., Bitcoin address with public key = 0)
- Deployed two ERC-20 tokens on Sepolia testnet using Metamask + Hardhat
- Implemented an Exchange (Token Swap) Contract with:
- Fixed-precision arithmetic
- Overflow protection & event logging
- Gas optimization considerations
- Tested on-chain swaps between deployed tokens
- Added and published files globally via public IPFS gateways
- Ran a local IPFS node behind a firewall, tunneling through a remote public server
- ✅ Python scripts for cryptanalysis & hashing
- ✅ Smart contract code (ERC-20 + Exchange contract)
- ✅ Deployment addresses & TX hashes (Sepolia network)
- ✅ PGP, SSH, and IPFS demonstrations
- ✅ Documentation of process & tools (OpenSSL, GPG, CrypTool)
This project brings together theory and practice in modern cryptography, blockchain security, Ethereum smart contracts, and decentralized storage systems.
It showcases hands-on skills in breaking ciphers, handling cryptographic keys, analyzing blockchain data, deploying ERC-20 tokens, building an exchange contract, and publishing content to IPFS.