Explore the world of cryptography through in-depth tutorials, historical analysis, cipher comparisons, and modern encryption concepts.
Hex and Base64 are two spellings of the same bytes. Hex costs 2 characters per byte, is case-insensitive and needs no padding; Base64 costs about 4 characters per 3 bytes but is case-sensitive and padded. Includes a size table computed with the site tools, a worked example, and a rule of thumb for choosing.
No key? Break a simple substitution cipher with frequency analysis: count the letters, match the most common ones to ETAOIN, then lock the rest with the word THE, single-letter words, and doubled letters. Includes a full worked example solved from real letter counts.
Faced with a mystery code? Identify an unknown cipher in three passes — character set first, then structure and length, then letter frequency — with a decision flow and the misreads that trip people up (Base64 vs hex, Atbash vs Caesar, and more).
The A1Z26 cipher replaces each letter with its position in the alphabet — A=1, B=2, up to Z=26 — so HELLO becomes 8-5-12-12-15. Here is the full A–Z table, how to encode and decode, and why the separators between numbers matter more than anything else.
Convert hexadecimal to readable text in three steps — split into byte pairs, turn each pair into a decimal number (0–255), then map that number to its ASCII character. Includes a worked example, a hex → decimal → character lookup table, and the reverse (text to hex).
The most-searched words in Morse code with copy-ready codes — SOS, HI, OK, HELP, HELLO and more — plus a letter-by-letter breakdown, why SOS is written as one group, and the CQ/73 signals.
Read Morse code with a full A-Z and 0-9 dot-dash chart, the timing rules that actually make it readable (dot, dash, and the 1/3/7 gaps), WPM and Farnsworth speed, and common signals like SOS.
The complete NATO phonetic alphabet (Alfa, Bravo, Charlie to Zulu) with official pronunciations, digit words like Niner and Fife, why it exists, and how to spell names and codes with it.
Convert binary to text in three steps: group into 8-bit bytes, read each byte as a decimal number, and map it to its ASCII character. Includes a full A-Z binary table, a worked example, and the reverse text-to-binary method.
Compare MD5 and SHA-256 hash functions by digest size, collision resistance, speed, file checksums, password risks, and safe use cases.
Compare AES and DES encryption, including security, key size, speed, history, and why AES replaced DES for modern data protection.
Learn how symmetric and asymmetric encryption differ, when each fits, and why modern security systems combine both approaches in real protocols.
Compare substitution and transposition ciphers by rules, examples, attacks, strengths, and teaching value for classical cryptography practice.
Compare Caesar and Atbash ciphers by key, mapping, history, security, and use cases so you know which tool fits your puzzle or lesson.
Discover how Arab scholars invented frequency analysis and turned cipher solving from educated guesswork into cryptanalytic science.
Learn how Room 40 decoded the Zimmermann Telegram, exposed Germany's Mexico plan, and helped push the United States into World War I.
Learn how Japan's Purple machine worked, how U.S. cryptanalysts broke it, and why MAGIC intelligence shaped WWII diplomacy and Pearl Harbor.
Jefferson sketched a 36-disk wheel cipher in the 1790s. See how it worked, why it mattered, and where its security lessons still apply.
How Mary Queen of Scots used a nomenclator cipher in the Babington Plot, how it was broken, and why the evidence led to her execution.
Explore ancient Hebrew ciphers in the Dead Sea Scrolls, from Atbash and cryptic scripts to Qumran secrecy, scribal practice, and modern lessons.
Explore Alan Turing's cryptography contributions, from Bombe logic and Banburismus to secure speech, computation, and modern lessons.
Explore how Navajo Code Talkers built a fast, layered voice code in World War II, why Japan never broke it, and what cryptography can learn.
Learn how the Enigma machine's rotors, plugboard, and procedures encrypted wartime traffic, and how Allied cryptanalysts systematically broke it.
Trace cryptography history from ancient Egyptian scribes to AES, and see how ciphers, codebreaking, and standards shaped modern security.
Learn how two-time pad attacks exploit reused keys, expose plaintext relationships, and reveal why one-time pad discipline matters in modern cryptography.
Understand why the one-time pad is theoretically unbreakable, what perfect secrecy really means, and why key reuse destroys it in practice.
Learn how columnar transposition cipher encryption and decryption work, how keywords set column order, and how to avoid decoding mistakes.
Learn how rail fence cipher encoding and decoding work, how rail count changes output, and how to fix zigzag transposition errors fast.
Beaufort and Vigenere look alike, but one reciprocal formula changes encryption, decryption, error checking, and cryptanalysis by hand.
Understand Hill cipher key matrices, determinant checks, modular inverses, and how to avoid invalid keys when encrypting or decrypting text.
Learn how the Hill cipher uses modular matrix math, work through encryption and decryption examples, and understand its strengths and limits.
Learn how the Playfair cipher works with grid setup, encryption rules, worked examples, common mistakes, and practical cryptanalysis tips.
Learn how ROT13 works, why it is not secure, and why this reversible Caesar variant still appears in forums, code jokes, and spoiler hiding.
Explore where the Atbash cipher appears in the Bible, how scholars decode names like Sheshach, and what it reveals about Hebrew cryptography.
Learn how to decode a Vigenere cipher without the key using Kasiski examination, frequency analysis, and practical step-by-step methods.
Learn how to use the Caesar cipher step by step with clear examples, a comparison table, common mistakes to avoid, and practice workflows for encoding and.
A Caesar cipher wheel turns letter-shifting into a physical dial. Print the free template, pin the two alphabet rings at the center, and encode or decode by reading straight across — with worked examples for shift 3, shift 5, and ROT13.