Rail Fence encode
Rail Fence encode, classical cipher, a puzzle not a protection, computed on your device.
Runs on your device. The file is never uploaded.
Rail Fence encode writes your text in a zigzag down and up across the rails you ask for, 3 by default. Each rail is then read out in turn into one string, carrying spaces and punctuation into new positions. Only the order changes, so letter frequencies survive and the rail count is the entire secret.
Questions
How does a rail fence work?
Your text is written diagonally down and up across a number of rails, then read off one rail at a time. It is a transposition cipher: the letters are the same, only their order changes, which is why the output has exactly your letter counts.
How many rails should I use?
More rails scramble more, up to a point. Two is the minimum the tool accepts, and anything lower is refused with "rails must be a whole number >= 2", because one rail never zigzags and would hand your text straight back. Whatever number you choose has to be used again to decode.
Does it keep spaces and punctuation?
They are transposed along with everything else, so they end up in new positions rather than being removed. That is worth knowing before you paste the result somewhere that treats spacing as meaningful.
How do I decode it?
Use Rail Fence decode with the same rail count. It rebuilds the zigzag pattern, works out how many characters sit on each rail, then reads them back in the original order.
Is it secure?
No. The number of rails is the whole key, so trying every plausible value takes seconds. Letter frequencies also survive transposition untouched, which hands an analyst the language immediately.