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Tool to decrypt/encrypt with a book cipher. The book cipher uses a book as an encryption index, each letter is coded by the rank of a word in the book.
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.
Caesar cipher: Encode and decode online. Method in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. The method is named after Julius Caesar, who used it in his private correspondence.
Tool to decrypt / encode like B. Arnold, using a book cipher (recovered messages from the 17th century).
The Vigenère cipher is a polyalphabetic encryption algorithm invented by the French cryptologist Blaise de Vigenère in the 16th century. It is based on a shift cipher to which is added the use of a keyword that changes the shift at each step.
A book cipher is a cipher in which each word or letter in the plaintext of a message is replaced by some code that locates it in another text, the key. A simple version of such a cipher would use a specific book as the key, and would replace each word of the plaintext by a number that gives the position where that word occurs in that book.
A book cipher uses a large piece of text to encode a secret message. Without the key (the piece of text) it is very difficult to decrypt the secret message. To implement a book cipher, each word in the secret message would be replaced with a number which represents the same word in the book.
