On the Subject of the Incremental Polyalphabetic CM

A machine that knows no bounds when it comes to ciphers.

This cipher uses 2 pages.

Concatenate the 6 keywords in this order: page 1 screen 1, page 1 screen 2, page 1 screen 3, page 1 screen 4, page 2 screen 1, page 2 screen 2. Remove any duplicate letters while keeping the first occurrences.

Write the entire alphabet above the newly created string. This will be referred to as the Polyalphabetic Key.

If the Submit Button is white, follow the instructions under Encrypt Instructions. Otherwise follow the instructions under Decrypt Instructions.

Encrypt Instructions

• Find the Nth letter of the encrypted word in the top row of the Polyalphabetic Key.
• Replace it with the letter below this letter.
• Perform this process a total of N times.

Decrypt Instructions

• Find the Nth letter of the encrypted word in the bottom row of the Polyalphabetic Key.
• The letter above this letter becomes your Nth decrypted letter.
• Perform this process a total of N times.

Example 1

Encrypted Word: VEDLDQAN
Keywords: BLOWFISH, QUIZ, VIXEN, TUCK, JUMPED, GERMANY
Key: BLOWFISHQUZVXENTCKJMPDGRAY
Using Encrypt Rules

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

B

L

O

W

F

I

S

H

Q

U

Z

V

X

E

N

T

C

K

J

M

P

D

G

R

A

Y

V → D
E → F → I
D → W → G → S
L → V → D → W → G
D → W → G → S → J → U
Q → C → O → N → E → F → I
A → B → L → V → D → W → G → S
N → E → F → I → Q → C → O → N → E

Decrypted Word: ORIGINAL

Example 2

Encrypted Word: ACBAGEPB
Keywords: SPECTRUM, JUKEBOX, WAGON, ADVERB, QUALIFY, HAZE
Key: SPECTRUMJKBOXWAGNDVQLIFYHZ
Using Decrypt Rules

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

S

P

E

C

T

R

U

M

J

K

B

O

X

W

A

G

N

D

V

Q

L

I

F

Y

H

Z

A → O
C → D → R
B → K → J → I
A → O → L → U → G
G → P → B → K → J → I
E → C → D → R → F → W → N
P → B → K → J → I → V → S → A
B → K → J → I → V → S → A → O → L

Decrypted Word: ORIGINAL