square box

this is a simple implementation of columnar transposition using a square box text encoding scheme.
do not use it for anything important! it may have been effective in the ancient greece, but it is no match for today's technology.
enter text to encode or decode:

explanation

this can be done by hand. arrange the message into a square grid and read it out vertically, column by column. the size of the grid is determined by the length of the string.

scrambling the string "this is a test" into "t ashi tist s e ":

t	h	i	s
	i	s
a		t	e
s	t

descrambling the string "t ashi tist s e ":

t		a	s
h	i		t
i	s	t
s		e