Tool directory

WWI German field cipher combining fractionation and transposition for military security.

Encrypt and decrypt with the ADFGX cipher, the WWI German field cipher that combines a 5x5 Polybius square with columnar transposition, broken by Georges Painvin in 1918.

Mathematical cipher using linear functions ax + b for letter substitution.

Encrypt and decrypt using the Alberti cipher, the first Western polyalphabetic cipher invented by Leon Battista Alberti in 1467. Uses two concentric disks with periodic rotation to defeat frequency analysis. Browser-based.

Simulate Leon Battista Alberti's 1467 cipher disk, the first polyalphabetic cipher. Two concentric rings rotate relative to each other, changing the substitution alphabet mid-message. Includes the historical 24-letter Italian alphabet and a visual disk rendering.

Encrypt or decrypt with the Amsco cipher, a columnar transposition variant that fills the grid with alternating 1- and 2-letter cells before reading columns in key order.

Reverses the alphabet mapping A to Z, B to Y, and so on for encoding.

Polysubstitution cipher that uses the plaintext itself as part of the encryption key.

Detect and decode Baconian cipher patterns in text composed of A and B characters.

Hide binary messages using two different fonts or character representations.

Encrypt or decrypt with the Bazeries cipher, Etienne Bazeries' product cipher that combines reversed group transposition with a keyed Polybius square substitution driven by one number.

Simulate the Bazeries Cylinder, Etienne Bazeries's 1898 French variant of the Jefferson Disk. Uses 20 rotating disks with historical scrambled alphabets. Encrypt and decrypt by aligning plaintext on one row and reading another row as ciphertext.

Decode the Beale ciphers using a book cipher with the Declaration of Independence. Solve Beale No. 2 and experiment with your own key texts for the unsolved No. 1 and No. 3.

Variant of Vigenère cipher using reciprocal mathematical operation for encryption.

Encrypt and decrypt using the Bifid cipher, invented by Felix Delastelle around 1901. Uses a keyword-based 5x5 Polybius square with fractionation to achieve diffusion.

Encrypt or decrypt with the Cadenus cipher, a columnar transposition that writes the message into 25-row columns, rotates each column by its key letter, and reads off by rows.

Transposition cipher that writes text into a square or rectangular grid row by row and reads it off column by column. Encode, decode, and brute-force with grid visualization.

Try all 25 Caesar cipher shifts at once with automatic ranking by likelihood.

Encrypt or decrypt messages by shifting letters through the alphabet.

Decode Caesar cipher text by trying all 25 shifts automatically, or use a manual shift slider for known keys.

Encrypt and decrypt with John F. Byrne's 1918 Chaocipher, a two-disk dynamic substitution cipher kept secret for 90 years and disclosed in 2010.

Encode and decode messages using the Chappe semaphore telegraph system from 1790s France. Visualizes the mechanical arm positions (regulator and two indicators) that transmitted messages across towers spanning hundreds of kilometers.

Encrypt and decrypt with the Alberti cipher disk, the first polyalphabetic cipher. Two concentric disks rotate to create substitution mappings. Visual SVG disk with configurable alphabets, shift, and periodic rotation.

Rotate an interactive Caesar cipher wheel to encrypt and decrypt messages visually. Drag the inner ring to change the shift.

Sophisticated transposition cipher using keyword columns to rearrange text.

Encode and decode the Dancing Men cipher from Arthur Conan Doyle's 1903 Sherlock Holmes story, a pictographic monoalphabetic substitution of stick-figure symbols.

Advanced cipher applying columnar transposition twice with dual keywords for enhanced security.

Simulate the WWII German Enigma cipher machine with configurable rotors, reflector, plugboard, and ring settings.

Dual-key digraph cipher using four 5x5 grids for enhanced substitution security.

Encrypt and decrypt using the Fractionated Morse cipher. Converts plaintext to Morse code, groups into triples, and substitutes with a keyed alphabet. ACA cipher and CTF challenge staple.

Encode and decode the Gold Bug cipher from Edgar Allan Poe's 1843 short story, a monoalphabetic substitution using digits and typographic symbols broken by frequency analysis.

Simulate the Great Cipher of Louis XIV, created by Antoine Rossignol in the 17th century. Uses a reconstructed codebook of syllables, words, and proper names with trap numbers (nulls). This cipher remained unbroken for 200 years until Etienne Bazeries cracked it in 1890.

Encrypt and decrypt with the Fleissner turning grille, a transposition cipher using a rotating mask with cut-out holes over a grid.

Gronsfeld variant with a running key generated from the initial key digits using a lag-2 Fibonacci recurrence mod 10.

Numeric key variant of Vigenère cipher popular in CTF competitions.

Matrix-based polygraphic cipher using linear algebra for block encryption.

Encrypt and decrypt with a homophonic substitution cipher that maps each plaintext letter to multiple ciphertext symbols to defeat frequency analysis.

Thomas Jefferson's cylindrical wheel cipher from the 1790s using 25 scrambled-alphabet disks, the basis for the US Army M-94.

Simulate the JN-25 Japanese naval code broken by US codebreakers before the Battle of Midway. Uses a 320-entry codebook of 5-digit naval terms plus an additive key (mod-10 digit addition). Includes historical context about Joseph Rochefort's Station HYPO.

Caesar cipher variant that builds a custom alphabet from a keyword before applying the shift. Encrypt and decrypt with keyword and shift visualization.

Build a monoalphabetic substitution alphabet from a keyword and encrypt or decrypt text.

Encrypt and decrypt with the Kryptos sculpture ciphers: keyed Vigenere (K1, K2) and route transposition (K3) using the modified KRYPTOS alphabet from Jim Sanborn's CIA artwork.

Simulate the WWII German Lorenz SZ40/42 cipher attachment (Tunny), a 12-wheel Vernam stream cipher broken at Bletchley Park with Colossus.

Simulate the M-94 (CSP-488) strip cipher used by the US Army from 1922 to 1943. Uses 25 aluminum strips with declassified scrambled alphabets. Arrange strips by key order, align plaintext, and read another row as ciphertext.

Columnar transposition where repeated key letters share a column group, a more complex variant of standard columnar transposition.

Russian revolutionary cipher combining a keyed Polybius square with numeric key addition for coordinate-based encryption.

Encrypt or decrypt with the Nihilist transposition cipher, a double transposition on a complete square that reorders both columns and rows by the keyword order.

Grid-based substitution cipher using geometric symbols to represent letters.

Digraph substitution cipher that encrypts pairs of letters using a 5x5 grid.

Encrypt or decrypt with the Pollux cipher, a Morse-based homophonic substitution that replaces each dot, dash, and separator with a digit from a 10-symbol key. Browser-based.

Ancient Greek coordinate system converting letters to numerical positions for signaling.

Renaissance polyalphabetic cipher using 13 reciprocal substitution pairs.

Simplified educational simulator of the Japanese Purple cipher machine used for diplomatic communications in WWII. Models the 6-20 vowel/consonant split and three cascaded 25-position stepping switches. Cracked by US codebreakers in 1940.

Simple transposition cipher that writes text in a zigzag pattern across multiple rails.

Simple letter substitution cipher that rotates letters by 13 positions.

Rotate all printable ASCII characters by 47 positions for text obfuscation beyond ROT13.

Encrypt and decrypt using the Route transposition cipher with seven route patterns including spiral, snake, diagonal, and straight reading orders. Configurable grid dimensions.

Uses long text passages like book content as the encryption key for enhanced security.

Ancient Spartan transposition cipher using cylindrical rod geometry.

Simplified educational simulator of SIGABA (ECM Mark II), the US WWII cipher machine designed by William Friedman and Frank Rowlett. Features 5 cipher rotors stepped irregularly by 5 control rotors through an index rotor, making it unpredictable and never broken.

Encrypt and decrypt using the Slidefair cipher, a Playfair variant that uses a sliding alphabet instead of a second Polybius square. Operates on digraphs with a configurable slide value (1-25) and optional Polybius keyword.

Bruce Schneier's 1999 card-deck-based stream cipher designed for field use without computers, featured in Neal Stephenson's Cryptonomicon.

Encrypt and decrypt using the straddling checkerboard cipher, a variable-length substitution used in the VIC cipher by Soviet spies. Keyword-based 10x3 grid with single and double digit codes.

Decode tap code from live audio input using the Web Audio API. Detects knocks and taps through your microphone, maps them to the 5x5 Polybius grid, and outputs decoded text in real time. Includes a manual input fallback for typed tap sequences.

Encrypt and decrypt using the Trifid cipher, invented by Felix Delastelle in 1902. Uses a 3x3x3 cube with triple fractionation and configurable period for greater diffusion than Bifid.

Encrypt and decrypt using the Trithemius progressive cipher, the first printed polyalphabetic cipher published in Polygraphia (1518). Uses a tabula recta with incrementing shift. Precursor to the Vigenère cipher. Browser-based.

Encrypt and decrypt with the Two-Square cipher (Double Playfair), a digraph substitution using two 5x5 keyword Polybius squares in vertical or horizontal layout.

Simplified educational simulator of Typex, the British WWII cipher machine and Enigma variant. Features 3 active rotors with Enigma-style stepping, 2 static stator rotors, and a reflector. Used by UK armed forces throughout the war.

Encrypt and decrypt text using the Vernam cipher, the XOR-based one-time pad that Shannon proved is perfectly secure.

Encrypt and decrypt using the VIC cipher, the Cold War hand cipher used by Soviet spy Reino Häyhänen. Combines a straddling checkerboard, chain addition, and double columnar transposition. Never broken by cryptanalysis. Browser-based.

Polyalphabetic substitution cipher using a keyword for enhanced encryption.

Auto-crack Vigenère ciphers using Kasiski examination and frequency analysis.