A columnar transposition, also known as a row-column transpose,
is a very simple cipher to perform by hand.
First, you write your message in columns. Then, you just rearrange the
columns. For example. I have the message, "Which wristwatches are swiss
wristwatches." You convert everything to upper case and write it without
spaces. When you write it down, make sure to put it into columns and number
them. Let's use five columns.
| | Unencoded | Rearranged |
|---|
|
Column #:
|
4 2 5 3 1
W H I C H
W R I S T
W A T C H
E S A R E
S W I S S
W R I S T
W A T C H
E S
|
1 2 3 4 5
H H C W I
T R S W I
H A C W T
E S R E A
S W S S I
T R S W I
H A C W T
S E
|
Now, you just read the columns down in the order that you number them.
Above, you will see the key is 4 2 5 3 1, which means you write down the
last column first, then the second, then the fourth, the first, and finally
the last. When you are all done, you will get
"HTHESTHHRASWRASCSCRSSCWWWESWWEIITAIIT". I can put the example's information
into the encoder for you:
Encode or
Decode
This columnar transposition cipher implementation will also move spaces
around, so you can take "a b c" with a key of "2 1" and get " abc" (note
the two spaces in front). I suggest you remove all spaces before you encode
the text, but they should be preserved even if you don't. Newlines are ignored and not taken into consideration.
This cipher is actually used in the Kryptos sculpture at the CIA
headquarters in what is generally known as K3 (the third section of the
sculpture), but this encoder will not give you the answer directly. You
still need to do work to see the decoded message.
This is your encoded or decoded text: