Free tools and resources helping you solve CTFs, ciphers, logic puzzles and room escape games.
Tool to decode A1Z26. The A1Z26 cipher is a simple substitution cipher that replaces each alphabet letter with its corresponding number (A=1, B=2, C=3, etc).
Tool to decode ADFGVX ciphers. The ADFGVX cipher was used by the German Army during World War I. It was invented by Lieutenant Fritz Nebel and is a fractionating transposition cipher which combines a Polybius square with a columnar transposition. The name comes from the six possible letters used.
Tool to decode ADFGX ciphers. The ADFGX cipher was used by the German Army during World War I. It was invented by Lieutenant Fritz Nebel and is a fractionating transposition cipher which combines a Polybius square with a columnar transposition. The name comes from the five possible letters used.
The Advanced Encryption Algorithm (AES) is also known by its original name, Rijndael (from the inventors). It has replaced DES as standard for encryption worldwide. It is available in versions with different key length, 128, 192 and 256 bits.
The Affine cipher is a monoalphabetic substitution cipher, where each letter in the alphabet is mapped to another letter through a simple mathematical formula (ax + b) mod 26. The number 26 represents the length of the alphabet and will be different for different languages.
Free anagram solver tool. From cryptic crosswords to board games, anagrams are one of the most commonly used forms of word puzzle. With a history dating back to ancient Greece, the desire to play with words has been a part of the human psyche for thousands of years.
Ascii table for all 7-bit printable characters. ASCII stands for American Standard Code for Information Interchange. It is a standard for character encoding in digital communications. This table contains the printable characters (letters, digits, punctuation characters and miscellaneous symbols).
This is a complete guide to the Atbash cipher and the tools you need to decode it. It’s one of the simplest ciphers to decode – once you’ve worked out that it is Atbash that you’re looking at.
Babylonian numerals uses a sexagesimal (base 60) number system. It was written in cuneiform, on soft clay tablets which later were exposed to the sun to harden. The legacy of the Babylonian numerals still survives today through the clock (60 minutes and seconds) and in trigonometry.
The Baconian cipher, or Bacon's cipher, is a method for steganography invented by Francis Bacon in 1605. The message is converted to a group of five code letters for each letter in the message. A false message is then written, where each letter is presented by the appropriate typeface for the corresponding code letter.
Barcode scanner and translation tool. The first barcode (or bar code) was invented by Norman Joseph Woodland and Bernard Silver, and patented in the US in 1952. Their barcode was based on Morse code, with thin and thick bars.
Base64 decoding tool. Base64 is an worldwide standard encoding to represent binary data in an ASCII string. Each Base64 character represents exactly 6 bits of data. Therefore, four Base64 characters represent three bytes of data.
Base64 encoding tool. Base64 is an worldwide standard encoding to represent binary data in an ASCII string. Each Base64 character represents exactly 6 bits of data. Therefore, four Base64 characters represent three bytes of data.
Baudot code decoding tool. The original Baudot code was invented by Émelie Baudot in 1870. It was a 5-bit code that became known as the International Telegraph Alphabet No 1(ITA1). In 1901, the code was improved by Donald Murray. Murray designed the code to minimize the wear on the machinery.
Tool to decrypt Beaufort ciphers. The Beaufort cipher is named after Sir Francis Beaufort. It is similar to the Vigenère, but the encryption and decryption is reciprocal (the encryption and decryption algorithms are the same). The Beaufort cipher is a polyalphabetic cipher.
Tool to decode bifid ciphers. The Bifid cipher was invented by the French amateur cryptographer Félix Delastelle around 1901. It is a fractionating transposition cipher, and was considered as a system of importance in cryptology. The Bifid cipher uses a Polybius square to achieve the fractionation.
Free and fast online Big Integer Number calculator. Just type in your numbers in decimal or hexadecimal format and click any button. This calculator can handle large numbers, with millions of digits, as long as they are integers.
Free tool for analysis of binary codes. Can detect many file formats and encodings including UTF-8, ASCII, Baudot-Murray codes, Baconian codes, images files, sound files, video files and zip files.
Free online binary to decimal converter tool. Just type any binary value into the field below and click Convert. This binary to decimal converter can handle big numbers, so you can type any number of binary digits.
This is a complete guide to book ciphers (also called book codes) and the tools you need to decode them. The numbering system can vary, but typically it is based on page numbers, line numbers, word numbers or character numbers.
Tool to translate the Braille alphabet. Braille is a tactile writing system for visually impaired people. It was created by Louis Braille, a Frenchman who lost his sight because of a childhood accident.
Decrypt any Caesar Cipher in different languages. This is a complete guide to the Caesar cipher and the tools you need to decode it.
This is a complete and detailed walkthrough/solution/writeup of the first Cicada 3301 puzzles and links to the tools you need to decode it. The Cicada 3301 is describes as one of the eeriest and strangest unsolved mysteries of the internet.
Stuck with a cipher or secret code? This free AI tool will help you identify the type of encryption and guide you how to decode and solve it.
Tool to decode columnar transposition ciphers. In a columnar transposition cipher, the message is written in a grid of equal length rows, and then read out column by column. The columns are chosen in a scrambled order, decided by the encryption key.
Free tool to convert between uppercase, lowercase and various forms of mixed case texts. Just paste in your text and choose the type of case conversion. You can also import text from a file and export the converted text to a file.
Stuck with a crossword or cryptogram? This free crossword solver helps you find those missing letters. Also includes advanced pattern search features to help you solve ciphers and cryptograms.
Cryptic crosswords are a special kind of crossword puzzles which are especially popular in the United Kingdom. Basically you have to read them the right way to find the solution. Usually what they seem to say when read normally is only a distraction.
Are you stuck solving a cryptogram? Read more about cryptograms and free available tools to solve them.
Tool to decrypt Dancing Men cipher. Dancing Men cipher was invented by Sir Arthur Conan Doyle and appeared in his story The Adventure of the Dancing Men. In this story, Sherlock Holmes discovers that the dancing figures is a secret cipher and cracks the code.
Free online decimal to binary converter tool. Just type any decimal number into the field below and click Convert. This decimal to binary converter can handle big numbers, so you can type any number of decimal digits.
Free online decimal to hex converter tool. Just type any decimal number into the field below and click Convert. This decimal to hex converter can handle big numbers, so you can type any number of decimal digits.
The Data Encryption Standard (DES) was developed in the early 1970s by IBM. After consultation with the National Security Agency (NSA), it was strengthened against differential cryptoanalysis, but weakened against brute-force attacks.
Tool to decode double transposition ciphers. The double transposition cipher is considered one of the most secure ciphers that can be performed by hand. It is equivalent to using two columnar transposition ciphers, with same or different keys.
The Elder Futhark is one of the oldest forms of the runic alphabet. It is also called Elder Fuþark, Older Futhark, Old Futhark and Germanic Futhark. It consists of 24 runes and is named after the first six runes F, U, ᚦ, A, R, K.
The Enigma machines were used during World War II by the Germans to protect their communications. It came in different models, but they all built on the same principles. It had a keyboard, rotors, a plugboard, a reflector and a lampboard to show the results.
The Euler Number (e) is a mathematical constant. It is named after the Swiss mathematician Leonhard Euler. It is considered one of the most important mathematical constants, alongside with 0, 1, π and i. Like π, it is an irrational number, having infinite decimals.
Some image file formats, such as JPG, store various metadata about their contents. This can be information such as where a photo was taken or which camera model was used. This can be useful information for puzzle solving, especially for geocaching or puzzles that involve coordinates.
Tool to decode four-square ciphers. The four-square cipher was invented by Félix Delastelle. It uses four 5x5 squares (where I and J share position, or Q is omitted). It translates letter two-by-two (digraphs) by matching them with letters in the key squares.
Free letter frequency analysis tool. Useful for analysing ciphers and cryptograms, detecting language, etc. Just paste your text and click the button. No ads, no limitations, no strings attached.
The Geek Code first was invented in 1993 by Robert Hayden and has still remained virtually unchanged. It is now considered a part of Internet cultural history, from before the internet became mainstream.
The Golden Ratio (φ) is a mathematical constant. Two numbers, a and b, are said to form the golden ratio if (a+b)/a = a/b = φ, for a > b > 0. Solving the equation yields φ = (1 + sqrt(5)) / 2. The Golden Ratio is also called the golden mean, divine proportion, divine section and golden number.
The Greek alphabet has been in use since around 800 BC. It was the first alphabet to have distinct letters for vowels as well as consonants. The Greek alphabet was derived from the Phoenecian alphabet and is the ancestor of the Latin and Cyrillic alphabets.
Tool to decrypt Gronsfeld ciphers. The Gronsfeld cipher, also called Bronckhorst cipher, was invented by José de Bronckhorst (earl of Gronsfeld) in 1744. It is similar to the Vigenère cipher, but uses digits instead of letters in the key.
Free online hex to decimal converter tool. Just type any hex value into the field below and click Convert. This hex to decimal converter can handle big numbers, so you can type any number of hex characters.
Tool to decrypt Hexahue code. Hexahue, and variants of it, are used occasionally in geocaching mystery caches, CTFs and logic puzzles. Look specifically for the color combinations to recognize it.
International Code of Signals maritime flags were first drafted by the British Board of Trade in 1855 and adopted as a world-wide standard on 1 January 1901. It is used for communications with ships.
Tool to decode keyed Caesar cipher. The keyed Caesar cipher is a variant of the Caesar Cipher that provides increased protection. Instead of having all letters in alphabetical order, it starts with a code word (the encryption key). Unused letters are then added after the code word.
Convert numbers to letters in various formats. Numbering the letters so A=1, B=2, etc is one of the simplest ways of converting them to numbers. This is called the A1Z26 cipher. However, there are more options such as ASCII codes, tap codes or even the periodic table of elements.
A very basic and classic method to hide a message in an image is to write it with nearly the same color as the background. In that way it will be invisible to the eye, unless you for example fill the background with another color.
Maya numerals was the number system of the Mayan civilization. It was a vigesimal (base 20) number system. The numerals are made up of three symbols, of which one denotes zero.
Free and fast online Modular Exponentiation (ModPow) calculator. Just type in the base number, exponent and modulo, and click Calculate. This Modular Exponentiation calculator can handle big numbers, with any number of digits, as long as they are positive integers.
Free and fast online Modular Multiplicative Inverse calculator. Just type in the number and modulo, and click Calculate. This Modular Multiplicative Inverse calculator can handle big numbers, with any number of digits, as long as they are positive integers.
Just type your text into the top box and it will be translated to Morse code using the international Morse alphabet. Can also be used for decoding Morse code.
Music offers many interesting ways of hiding messages. An early example is, Tre rebus musicali, written by Leonardo da Vinci. Many great classical composers have included musical cryptograms in their works. Nowadays, audio steganography tools can hide anything in any music.
The one-time pad (OTP) is a theoretically unbreakable cipher. However, in practice it is of limited usability because it requires a pre-shared key of at least the same length as the message. This tool helps you encode or decode one-time pads if you have the key.
OpenPuff is a steganography tool for Microsoft Windows that supports a wide range of formats (images, audios, videos) for embedding hidden data. OpenPuff is partially open source.
Outguess is a steganography tools that allows a user to embedd hidden data inside of a JPEG-image file (and some other image formats). It stores the data by modifying redundant information, so that it doesn't cause visual changes to the image.
Pi (π) is a mathematical constant, the ratio of the circumference of a circle to its diameter. It appears in many formulas in all areas of mathematics. Sometimes it is called Archimedes' constant. Being an irrational number, π has an infinite number of decimals.
Tool to translate pigpen cipher. Pigpen cipher is a monoalphabetic substitution cipher, where the letters are replaced by geometric symbols. It is also known as masonic cipher, Freemason's ciper, Napoleon cipher and tic-tac-toe cipher.
Online tool to extract pixel values from images of most file formats (include .jpg, .tif, .png, gif, etc). Your images will be converted to numerical values. Either 0 or 1 for the black/white modes, or 0-255 for the other modes. You can also customize the delta.
Tool to decrypt Playfair ciphers. The Playfair cipher was invented in 1854 by Charles Wheatstone, but named after lord Playfair who heavily promoted the use of the cipher. It is a polygraphic substitution cipher, which encrypts pair of letters instead of single letters.
Prime numbers testing and search tool. A prime number is a natural number that cannot be formed by multiplying two smaller natural numbers. The number 1 is a special case, which is not considered a prime number.
QR Code scanner and translation tool. The QR Code was invented by Japanese company Denso Wave Inc in 1994. It can store data efficiently and also handle scanning errors due to the Reed-Solomon error correction. The QR Code is one of the most popular two-dimensional barcodes.
Quantum computing is a rapidly evolving technology that can completely change the way we look at computer science. Using quantum computers, the hardest computational problems (NP problems or even NPC problems) could be solved in polynomial time, rendering most of current crypto algorithms useless.
Tool to decode rail fence ciphers. The rail fence cipher is a simple transposition cipher. It is also known as a zigzag cipher. In a rail fence cipher, the plaintext letters are written diagonally in a up-down pattern from left to right.
The RC4 (Rivest Cipher 4) is a stream cipher invented by Ron Rivest in 1987. It is known for high speed and simplicity in software implementations. However, multiple vulnerabilities have been discovered in RC4, rendering it insecure.
Free tool to remove accents (diacritic marks) from text. Just paste in your text and click the remove accents button. You can also import text from a file and export the cleaned up text to a file. No ads, no limitations, no strings attached.
Free tool to remove unwanted spaces, tabs, newlines or punctuation. Just paste in your text and choose the type of removal. You can also import text from a file and export the cleaned up text to a file. No ads, no limitations, no strings attached.
This tool reverses the order of characters in your text. Paste or type your text in the input box and click the button to reverse it. Useful for fun, puzzles, or encoding messages.
Roman numerals originated in ancient Rome and remained in use in Europe well into the late middle ages. Roman numbers are represented by a combination of letters from the latin alphabet.
This is a complete guide to the ROT13 cipher and the ROT47/ROT18 variants. ROT13 is a shift cipher, that’s a simple kind of encryption where the ciphertext is created by taking the plain text message and shifting (moving forward in the alphabet) by a certain number of letters.
This tool helps you solve route transposition ciphers. Just enter your text and experiment with the column length and transposition type to search for solutions for your cipher.
The RSA crypto is one of the first public-key cryptosystems. The encryption key is public, while the decryption key is secret. It is constructed using two large prime numbers. It is named after the inventors, Ron Rivest, Adi Shamir and Leonard Adleman.
Tool to translate flag semaphores. Semaphore flags is a telegraphy system to communicate at a distance by means of visual signals. It can use hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands.
Spectrograms is a method of hiding images inside of an audio or video file. Basically the y-scale is represented by frequencies, while the x-scale represents time. The result is weird sounds and strange sound patterns. For example the viral 11B-X-1371 video used this method to embed creepy images.
Steghide is a steganography tool for Linux and Microsoft Windows that supports JPEG, BMP, WAV and AU files. Steghide is open source.
Single-image stereograms, or autostereograms, are images that when viewed correctly gives the perception of 3D depth. Viewing them requires some training, as our eyes are not used to converging/diverging our focus. Tools can therefore be helpful for those who have difficulties seeing the 3D shapes.
Tool to automatically or manually solve substitution ciphers. The substitution ciphers is one of the oldest classical ciphers. Each letter is replaced by a different letter of the alphabet, so solving the puzzle means finding out the original lettering.
Clues to code-breaking puzzles are frequently expressed as synonyms or related words. Also antonyms (words with opposite meanings) are sometimes used. With a thesaurus, you will find a list of all synonyms for a given word.
Tap code is a way to encode text messages, commonly used by prisoners. This tool translates text to and from tap code, using a Polybius square. Enter your message below to encode or decode.
Free tool for analysis of cipher texts.
Tool to extract texts from binary (non-text) files. Search any binary file, such as an executable, for text strings of printable characters. This tools is similar to the Linux strings command, but you run it directly here in your web browser. The tool supports both ASCII and Unicode formats.
Free tools for code-breaking, solving ciphers and logic puzzles, room escape games, CTFs, Cicada 3301 and more.
Tool to decode Trifid ciphers. The Trifid cipher was invented by the French amateur cryptographer Félix Delastelle and described in 1902. It is an extension of the bifid cipher, from the same inventor. The Trifid cipher uses trigrams instead of bigrams to fractionate the letters.
Unicode is the worldwide standard for encoding and representing text in most of the world's writing languages, maintained by the Unicode Consortium. Currently Unicode has over 137000 different characters, covering both modern and historical languages as well as symbols and emojis.
Tool to turn your text into upside down text that can be pasted into Facebook, Twitter, blogs, forums and more. The tool uses the Unicode alphabet to play this visual trick. The upside down text can either be presented as rotated or mirrored.
UTF-8 decoding online tool. UTF-8 (8-bit Unicode Transformation Format) is a variable length character encoding that can encode any of the valid Unicode characters. Each Unicode character is encoded using 1-4 bytes. Standard 7-bit ASCII characters are always encoded as a single byte in UTF-8.
UTF-8 encoding online tool. UTF-8 (8-bit Unicode Transformation Format) is a variable length character encoding that can encode any of the valid Unicode characters. Each Unicode character is encoded using 1-4 bytes. Standard 7-bit ASCII characters are always encoded as a single byte in UTF-8.
Tool to decrypt Variant Beaufort ciphers. In the variant Beaufort cipher, encryption is performed like decryption in the Vigenère cipher, and decryption is performed like encryption in the Vigenère cipher, so it is in practice a "variant Vigenère cipher".
This is an online tool and complete guide to the Vigenère cipher and how to solve it. Perfect for puzzle enthusiasts and code breakers!
Unscramble words, find words within words and make words from any letters. This free tool will descramble any letters into possible words. Solve anagrams and words puzzles.
When it comes to enduring puzzles, the zodiac ciphers are amongst the most infamous. They combine the fascination with true crime, and serial killers, with a cipher that tantalizes the amateur cryptologist. There are four encrypted communications received from the Zodiac Killer, but so far only one of them has been solved.