Tool for encrypting and decrypting medieval codes (extended Middle Ages period), links to various interactive online ciphers/codes/alphabets.
Medieval Ciphers - dCode
Tag(s) : Cryptography
dCode is free and its tools are a valuable help in games, maths, geocaching, puzzles and problems to solve every day!
A suggestion ? a feedback ? a bug ? an idea ? Write to dCode!
Medieval Ciphers
Ciphers and Secret Codes in the Middle Ages
The medieval period (approximately 500-1500 AD) was marked by significant developments in the art of secret communication.
List of medieval codes and alphabets
Atbash Cipher (~-600) - An ancient Hebrew numeral where the first letter of the alphabet replaces the last. It was used in biblical texts and persisted in medieval Hebrew writings.
Scytale Cipher (~-500) - A Greek staff for encrypting messages by wrapping a strip of parchment around it.
Caesar Cipher (~-50) - Dating back to ancient Rome, the Caesar cipher (a simple shift cipher) remained in use throughout the Middle Ages. See also Shift Cipher
Ogham Alphabet (~500) - The Celtic Ogham alphabet, with its distinctive linear strokes carved on stones or wood.
Lingua Ignota (~1150) - Created by Hildegard of Bingen, this constructed language included an alphabet called Litterae Ignotae.
Theban Alphabet (~1300) - Attributed to Honorius of Thebes, this symbolic alphabet appeared in medieval grimoires to encode occult texts and rituals.
Alberti Cipher (~1450) - A revolutionary encryption disk that introduced polyalphabetic substitution. It is considered a foundation of modern cryptography.
Trithemius Ave Maria (~1500) - Beneath the guise of a prayer lies a steganographic encryption, concealing messages within religious writings.
Celestial Alphabet (~1500) - Also known as angel writing, this alphabet was associated with Kabbalistic and occult traditions. See also Enochian Alphabet, Malachim Alphabet, Passing the River Alphabet
Pigpen Cipher (~1550) - Inspired by medieval methods, this code transforms letters into geometric symbols. Simple and visual, it was notably adopted by Freemasons. Templars Cipher is a variant later used by the Knights Templar.
Answers to Questions (FAQ)
What is a medieval cipher? (Definition)
Medieval ciphering refers to a method used in the Middle Ages to transform a readable (plaintext) message into an unintelligible (ciphertext) one.
These methods primarily relied on substitution (replacing each letter or symbol with another) and transposition (changing the order of the letters without altering them).
These techniques were mainly used for diplomatic, military, and religious communications to protect sensitive information.
What are the most famous medieval ciphers?
Monoalphabetic substitutions – each letter replaced by another letter or symbol, or more; basically, substitutions by shifting the alphabet
Example: Caesar cipher
Polyalphabetic substitutions (only in the late Middle Ages/early Renaissance)
Example: Alberti cipher then Vigenère cipher
Transposition ciphers – reorganization of the letters of the message without changing them.
Example: Scytale
Nomenclators – a mixture of substitution ciphers and code lists for names/words
How did substitution ciphers work in the Middle Ages?
Medieval substitution was a letter-by-letter replacement. Several variations existed:
— Monoalphabetic: a single substitution rule for the entire message (A becomes X, B becomes Y).
— Polyalphabetic: several substitution alphabets are used successively.
— Symbolic: replacement of letters with graphic symbols.
Are there any examples of medieval steganography?
Yes, although direct evidence is rare.
— Invisible inks: organic substances (like lemon juice) revealed by heating or treatment.
— Hidden messages in religious texts: acrostics, initial letters, or phrases concealed within prayers.
— Everyday objects: inscriptions hidden on rings, belts, or discreetly integrated into illuminated manuscripts.
Source code
dCode retains ownership of the "Medieval Ciphers" source code. Any algorithm for the "Medieval Ciphers" algorithm, applet or snippet or script (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, breaker, translator), or any "Medieval Ciphers" functions (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) or any database download or API access for "Medieval Ciphers" or any other element are not public (except explicit open source licence). Same with the download for offline use on PC, mobile, tablet, iPhone or Android app.
Reminder: dCode is an educational and teaching resource, accessible online for free and for everyone.
Cite dCode
The content of the page "Medieval Ciphers" and its results may be freely copied and reused, including for commercial purposes, provided that dCode.fr is cited as the source (Creative Commons CC-BY free distribution license).
Exporting the results is free and can be done simply by clicking on the export icons ⤓ (.csv or .txt format) or ⧉ (copy and paste).
To cite dCode.fr on another website, use the link:
In a scientific article or book, the recommended bibliographic citation is: Medieval Ciphers on dCode.fr [online website], retrieved on 2026-02-13,
