Double Transposition Cipher Examples (encoder / decoder)

1. Double Transposition Cipher encoder

Text : ABCD efghi 1234
Key1 : key
Key2 : word
Remove Special Characters (except a-z0-9) : True

Solution:

The double transposition cipher applies on columnar transposition cipher twice with two keys

Columnar transposition on Plaintext using Key1 : key

Write the plaintext in row-by-row

k 2	e 1	y 3
a	b	c
d	e	f
g	h	i
1	2	3
4	_	_

The columns are sorted alphabetically, based on the keyword and the new table is

e 1	k 2	y 3
b	a	c
e	d	f
h	g	i
2	1	3
_	4	_

Read the ciphertext in column-by-column
beh2,adg14,cfi3

Plaintext	: abcdefghi1234
Key	: key
Ciphertext	: beh2adg14cfi3

Columnar transposition on this Ciphertext-1 using Key2 : word

Write the plaintext in row-by-row

w 4	o 2	r 3	d 1
b	e	h	2
a	d	g	1
4	c	f	i
3	_	_	_

The columns are sorted alphabetically, based on the keyword and the new table is

d 1	o 2	r 3	w 4
2	e	h	b
1	d	g	a
i	c	f	4
_	_	_	3

Read the ciphertext in column-by-column
21i,edc,hgf,ba43

Plaintext	: beh2adg14cfi3
Key	: word
Ciphertext	: 21iedchgfba43

Plaintext	: abcdefghi1234
Key1	: key
Ciphertext-1	: beh2adg14cfi3
Key2	: word
Ciphertext	: 21iedchgfba43

2. Double Transposition Cipher encoder

Text : hello world 1234
Key1 : key
Key2 : word
Remove Special Characters (except a-z0-9) : True

Solution:

The double transposition cipher applies on columnar transposition cipher twice with two keys

Columnar transposition on Plaintext using Key1 : key

Write the plaintext in row-by-row

k 2	e 1	y 3
h	e	l
l	o	w
o	r	l
d	1	2
3	4	_

The columns are sorted alphabetically, based on the keyword and the new table is

e 1	k 2	y 3
e	h	l
o	l	w
r	o	l
1	d	2
4	3	_

Read the ciphertext in column-by-column
eor14,hlod3,lwl2

Plaintext	: helloworld1234
Key	: key
Ciphertext	: eor14hlod3lwl2

Columnar transposition on this Ciphertext-1 using Key2 : word

Write the plaintext in row-by-row

w 4	o 2	r 3	d 1
e	o	r	1
4	h	l	o
d	3	l	w
l	2	_	_

The columns are sorted alphabetically, based on the keyword and the new table is

d 1	o 2	r 3	w 4
1	o	r	e
o	h	l	4
w	3	l	d
_	2	_	l

Read the ciphertext in column-by-column
1ow,oh32,rll,e4dl

Plaintext	: eor14hlod3lwl2
Key	: word
Ciphertext	: 1owoh32rlle4dl

Plaintext	: helloworld1234
Key1	: key
Ciphertext-1	: eor14hlod3lwl2
Key2	: word
Ciphertext	: 1owoh32rlle4dl

This material is intended as a summary. Use your textbook for detail explanation.
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1. Examples