The scytale is a transposition cipher from ancient Sparta: a strip was wound around a rod, the message was written along it, and once unwound the strip was a jumble of letters. The letters stay the same, only their order changes. The key is the number of sides of the rod, that is the number of rows, from 2 to 20.
Everything runs in your browser — the text goes nowhere
The link will contain the text (up to 500 characters) and settings — share it with care.
02
Diagram
a table of 3 rows
WEARE
DISCO
VERED
Shows the first line of the text, up to 60 characters.
03
How it works
Rows and columns
WEARE / DISCO / VERED
The text goes row by row into a table of k rows and is read column by column: WDVEIEASRRCEEOD.
The key is the rod
k = number of sides
How many letters fit in one turn of the strip. Without a rod of the same thickness the strip is a jumble.
No padding
the last row is shorter
The text is not padded with extra letters: decoding accounts for the short row by itself.
04
Frequently asked questions
The text is written row by row into a table of k rows and read column by column, top to bottom and left to right. WEAREDISCOVERED with k = 3 is laid out as WEARE, DISCO, VERED and read down the columns as WDVEIEASRRCEEOD. Letters are not replaced, only moved, so the ciphertext has exactly the letters of the original.
The key is the thickness of the rod, or more precisely its number of sides: how many letters fit in one turn of the strip. In the table it is the number of rows. Without a rod of the right size the strip reads as nonsense; with it the letters line up again. Here the key is a number from 2 to 20.
By trying keys: there are few, and for each one you only need to see whether the text makes sense. Open the Decode tab and change the number of rows with the minus and plus buttons; at one of the values, words appear. For a short note it takes a minute or two, which is why the scytale is a teaching cipher rather than real protection.
A space is a character like any letter and gets moved too: in the ciphertext it lands somewhere random and gives away word lengths. That is why spaces are usually removed before encoding, and the Remove spaces box does exactly that. No padding is needed: the last row of the table may be shorter, and decoding takes that into account.
Ancient Greek authors describe the scytale, Plutarch among them in his Life of Lysander: Spartan commanders received strips with orders and read them on a rod as thick as the sender's. It is one of the earliest known transposition ciphers and is still shown in classrooms, because you can see the idea with a pencil and a strip of paper.
No. The transposition runs in your browser on your device; the text is not sent to a server and does not appear in the page address. Only the Share button builds a link with the text and the number of rows, and the note under it says what goes in. The site counter records only that the tool was used.