Learn Cryptography
Explore the fascinating world of classical cryptography with comprehensive tutorials, guides, and interactive examples
Cipher Categories
Caesar Cipher
Articles about Caesar cipher and shift-based encryption methods
Vigenère Cipher
Polyalphabetic substitution cipher tutorials and guides
Playfair Cipher
Digraph substitution cipher implementation and analysis
Affine Cipher
Mathematical substitution cipher using linear transformations
Hill Cipher
Matrix-based polygraphic substitution cipher tutorials
Vernam Cipher
One-time pad and perfect security encryption methods
Beaufort Cipher
Self-reciprocal variant of Vigenère cipher guides
Atbash Cipher
Ancient Hebrew mirror substitution cipher tutorials
Pigpen Cipher
Geometric symbol-based substitution cipher guides
Polybius Cipher
Coordinate-based ancient Greek encryption methods
Keyword Cipher
Monoalphabetic substitution cipher tutorials and cryptanalysis guides
Calculators
Date calculators, math tools, and utility guides for everyday calculations
Converters
Number system converters, encoding tools, and unit conversion guides
Baconian Cipher
Francis Bacon's binary steganographic cipher tutorials and guides
Porta Cipher
Della Porta's 13-table reciprocal polyalphabetic cipher guides
Gronsfeld Cipher
Numeric-key Vigenère variant cipher tutorials and analysis
Trithemius Cipher
Tabula recta and progressive-key cipher guides
Alberti Cipher
The first polyalphabetic cipher disk system tutorials
Homophonic Cipher
Homophonic substitution cipher tutorials and Zodiac Killer analysis
Four-Square Cipher
Delastelle's digraph encryption system tutorials and guides
Autokey Cipher
Self-keying Vigenère variant cipher tutorials and cryptanalysis
Quagmire Cipher
ACA's advanced polyalphabetic substitution cipher with four variants
Morse Code
Morse code encoding, translation, history, and learning guides
Frequency Analysis
Letter frequency analysis, cryptanalysis techniques, and cipher breaking guides
Running Key Cipher
Running key cipher tutorials using book passages as encryption keys
Straddling Checkerboard
Straddling checkerboard cipher and VIC cipher Cold War espionage guides
Recent Articles
How Cryptographic Hash Functions Work — MD5 vs SHA-256 vs SHA-512 Explained
Complete guide to cryptographic hash functions covering MD5 vs SHA-256 vs SHA-512 comparison, how hashing works internally, collision attacks, password hashing best practices with bcrypt and Argon2, HMAC authentication, and applications in blockchain, TLS, and Git.
Subnetting Tutorial: CIDR Notation, Subnet Masks & IP Addressing Explained
Complete subnetting tutorial covering CIDR notation, subnet masks, wildcard masks, IP address classes, private IP ranges, VLSM, cloud networking, and three worked examples with a subnet cheat sheet.
Sales Tax by State 2026: Complete Guide to US Sales Tax Rates & Rules
Complete 2026 guide to US sales tax covering all 50 state rates, five no-tax states, calculation formulas with worked examples, reverse tax calculation, tax-exempt items, vehicle sales tax, Sales Tax vs VAT, IRS SALT deduction, and the Wayfair online sales tax decision.
Running Pace Chart: 5K, 10K, Half Marathon & Marathon Finish Times
Comprehensive running pace chart covering finish times for every major race distance, pace-to-speed conversion, treadmill speed tables, training pace zones, average pace by age and gender, and race day pacing strategies.
How to Read Binary Code: Complete Guide to Binary Translation
Complete guide to reading binary code covering bits, bytes, positional notation, step-by-step decoding, ASCII and Unicode encoding, common words in binary, programming examples in Python and JavaScript, and comparison with other number systems.
Unix Timestamp Explained: What Is Epoch Time and How Developers Use It
Complete guide to Unix timestamps and epoch time covering why developers use them, seconds vs milliseconds, programming examples in seven languages, Excel formulas, notable timestamps, the Year 2038 problem, and leap second handling.