Progressive Key Cipher solver calculator (encoder / decoder)

SolutionHelp

Solution (Print / Save)

Solution provided by AtoZmath.com

1. ABCD efghi

2. hello world

Example (with steps)

1. Progressive Key Cipher encoder

Text : ABCD efghi jklmn
Substitution Cipher Method : vigenere
Key : start
Progressive Key (Shift By) : 1
Alphabet : abcdefghijklmnopqrstuvwxyz

Solution:

The Progressive Key cipher is a Periodic substitution cipher that uses a keyword which is shift progressively (+1) with each next group, making it more secure. It can be used with any of the Periodic Substitution Cipher: Vigenere, Beaufort, Variant Beaufort, Porta Cipher.

Alphabet = abcdefghijklmnopqrstuvwxyz

Letter	a	b	c	d	e	f	g	h	i	j	k	l	m	n	o	p	q	r	s	t	u	v	w	x	y	z
Number	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25

Each letter is shifted down based on the key letter

Plaintext	A	B	C	D	e	f	g	h	i	j	k	l	m	n
Text Value (2)	0	1	2	3	4	5	6	7	8	9	10	11	12	13
Key	s	t	a	r	t	s	t	a	r	t	s	t	a	r
Key Value (4)	18	19	0	17	19	18	19	0	17	19	18	19	0	17
Progressive Key Shift (5)	0	0	0	0	0	1	1	1	1	1	2	2	2	2
Addition (2) + (4) + (5) Mod 26	18	20	2	20	23	24	26=0	8	26=0	29=3	30=4	32=6	14	32=6
Ciphertext	S	U	C	U	x	y	a	i	a	d	e	g	o	g

So finally

Plaintext	: ABCD efghi jklmn
Key	: start
Ciphertext	: SUCU xyaia degog

2. Progressive Key Cipher encoder

Text : hello world, how are you
Substitution Cipher Method : vigenere
Key : start
Progressive Key (Shift By) : 1
Alphabet : abcdefghijklmnopqrstuvwxyz

Solution:

Alphabet = abcdefghijklmnopqrstuvwxyz

Letter	a	b	c	d	e	f	g	h	i	j	k	l	m	n	o	p	q	r	s	t	u	v	w	x	y	z
Number	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25

Each letter is shifted down based on the key letter

Plaintext	h	e	l	l	o	w	o	r	l	d	,	h	o	w	a	r	e	y	o	u
Text Value (2)	7	4	11	11	14	22	14	17	11	3		7	14	22	0	17	4	24	14	20
Key	s	t	a	r	t	s	t	a	r	t		s	t	a	r	t	s	t	a	r
Key Value (4)	18	19	0	17	19	18	19	0	17	19		18	19	0	17	19	18	19	0	17
Progressive Key Shift (5)	0	0	0	0	0	1	1	1	1	1		2	2	2	2	2	3	3	3	3
Addition (2) + (4) + (5) Mod 26	25	23	11	28=2	33=7	41=15	34=8	18	29=3	23		27=1	35=9	24	19	38=12	25	46=20	17	40=14
Ciphertext	z	x	l	c	h	p	i	s	d	x	,	b	j	y	t	m	z	u	r	o

So finally

Plaintext	: hello world, how are you
Key	: start
Ciphertext	: zxlch pisdx, bjy tmz uro