Type your text and set the number of rails (2-10), and the tool encrypts it by writing it in a zigzag pattern across that many rows.
Characters are written diagonally down and up across a number of 'rails' (rows) in a zigzag pattern, then read off row by row to produce the ciphertext. It's a transposition cipher — it rearranges letters rather than substituting them.
Any number from 2 to 10. More rails create a more scrambled result. Note that using 1 rail leaves the text unchanged (identity).
Yes — the tool reconstructs the zigzag pattern from the ciphertext length, so decoding an encoded message with the same rail count returns your exact original text, including spaces and punctuation.