Type your text and a keyword, and the tool encrypts it by writing it into columns and reading them back out in the keyword's alphabetical order.
The message is written in rows beneath a keyword. Columns are then read off in the alphabetical order of the keyword letters to form the ciphertext. It rearranges letters rather than substituting them.
Each keyword letter is ranked alphabetically (ties broken left to right). For example 'ZEBRAS' ranks its columns 6-3-2-4-1-5, so column A is read first, then B, then E, and so on.
Yes. The tool recomputes each column's length from the message length and keyword, so decoding with the same keyword returns your exact original letters. Encrypting 'WEAREDISCOVEREDFLEEATONCE' with 'ZEBRAS' gives 'EVLNACDTESEAROFODEECWIREE'.