Trevanion Cipher

Encryption involves taking a text and be pay attention to position of the punctuation so that after each sign, counting a number of letters (eg 3 letters) we find a letter from the hidden message.

Decryption requires to know of the shift N used.

To find the plain text it is necessary to browse the text in search of the signs of punctuation. After each one, count a number of characters (N) to find a new letter of the plaintext.

Example: This website, I admit, is cool ! Prodigious tools, so dazzling things here. Great job !

Example: With N=3, The original plain text is DCODE.

The message, if well done, is theoretically impossible to recognize.

dCode can attempt the most classic combinations, different shifts and modes.

It is possible to set the trigger characters, eg. to use characters other than the classical punctuation.

The method for calculating the offset may be different for each person, some will count for all characters, others will treat only letters.

Example: `GO ! ATTACK !' has for 3rd letter A, for 3rd character _ (space) or ! (if space is ignored).

17th century but the author is probably not John Trevanion. The name of this code was given in honor of John Trevanion, an English, a prisoner who received a letter from a friend using this principle. But historians have found inconsistencies in this story.