Intro to Computer Security

Cryptography study hub — 2-day exam prep

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Today + tomorrow. Path: Crypto Landscape → Intro Playlist Concepts → DES Feistel Round → DES Key Schedule → RC4 Keystream → RSA Modular Math → Diffie-Hellman & RSA → SHA-1 Padding → SHA-1 Compression

Study plan progress: —

Open Study Plan Crypto Landscape

Study plan

2 days

2-Day Study Plan

Day 1: DES + RC4. Day 2: DH, RSA, SHA-1 + timed exam. Interactive checkboxes.

Reference

Algorithm Cheat Sheet

One-page formulas and canonical exam numbers. Print-friendly.

Exam path (follow in order)

Step 1 · Crypto Landscape

The Cryptography Landscape

Symmetric vs asymmetric, cipher vs hash, where each algorithm fits.

Step 2 · Intro Playlist Concepts

Intro Playlist Concepts

CIA, security layers, threats, Sec-SDLC — from professor's 9 intro videos.

Step 3 · DES Feistel Round

DES Feistel Round

f-function, S-box lookup, worked round-1 example.

Step 4 · DES Key Schedule

DES Key Schedule

PC-1, left shifts, PC-2 — worked K₁ and K₂.

Step 5 · RC4 Keystream

RC4 Keystream

KSA + PRGA. 3-bit and 4-bit worked solutions.

Step 6 · RSA Modular Math

RSA Modular Math

Extended Euclidean (d=59) + successive squaring (C=98).

Step 7 · Diffie-Hellman & RSA

Diffie-Hellman & RSA

Key agreement, modular exponentiation, encrypt/decrypt concepts.

Step 8 · SHA-1 Padding

SHA-1 Padding

512-bit block layout, padding arithmetic, visual bit diagram.

Step 9 · SHA-1 Compression

SHA-1 Compression

W expansion, 80-round overview, professor doc format.

Reference

DES S-box Lookup

Row/column rule with diagram. Use during DES drills.

Glossary

Canonical terms — print-friendly HTML.

RSA Math Cheat Sheet

Extended Euclidean template + successive squaring for M=21→C=98.

Your RC4 Notes

Original lecture notes — 3-bit and 4-bit solutions complete.

External resources

Lecture videos (Arabic)