Computer and Network Security

CTIS-496 Computer and Network Security Project (Part 1 - Part 2 - Part 3)

Part 1: Focuses on OpenPGP-based secure communication using GPG, Thunderbird, and public keyservers

Key Tasks

• Generating PGP key pairs (RSA, 4096 bits) for secure email.
• Importing/exporting public and private keys using GPG and Thunderbird.
• Uploading public keys to a public keyserver and verifying key fingerprints.
• Sending encrypted and digitally signed emails via Thunderbird.
• Creating and verifying digital signatures for files using GPG.
• Managing key trust levels and signing each other’s public keys.
• Verifying software authenticity using signature files and GPG.

Part 2: Focuses on public key infrastructure (PKI) and secure email communication with Thunderbird, OpenSSL, and X.509 certificates.

Key Tasks

• Obtaining and managing S/MIME certificates from Actalis.
• Configuring secure email accounts with encryption and digital signatures.
• Extracting public certificates and working with PEM, P12 formats.
• Inspecting web server certificates via OpenSSL.
• Analyzing Certificate Revocation Lists (CRLs).
• Creating and inspecting self-signed certificates, completing advanced SEED Labs on PKI.

Part 3: Focuses on applied cryptanalysis, image encryption, and secure coding standards

Key Tasks Performed hand-based cryptanalysis of the Affine Cipher, including manual key recovery through algebraic equations.

• Solving Affine cipher challenges using manual key recovery.
• Creating and encrypting substitution ciphers with custom keys.
• Applying known plaintext attacks on permutation ciphers to find candidate keys.
• Encrypting images with AES-128 in ECB and CBC modes using OpenSSL and GIMP.
• Comparing visual differences in ECB and CBC encryption modes.
• Documenting encryption steps with basic Linux/Unix commands.
• Writing a secure code based on SEI CERT coding standards.