HAND ENCRYPTION

Four Methods of Encryption Using Pencil and Paper



I: ADFGVX Cipher Variant

This is a variation on the ADFGVX cipher used by Germany in WWI

First a keyword of 8 non-repeating letters, such as the word tropical, is set up in a grid using two scrambled alphabets, ten digits,, a period, and ampersand as in the following example:

 

T

R

O

P

I

C

A

L

T

S

E

C

U

R

I

T

Y

R

A

B

D

F

G

H

J

K

O

L

M

N

O

P

Q

V

W

P

X

Z

T

R

O

P

I

C

I

A

L

B

D

E

F

G

H

C

J

K

M

N

Q

S

U

V

A

W

X

Y

Z

1

2

3

4

L

5

6

7

8

9

0

.

&

Using the intersections of rows and columns this yields the following table:

A is encoded as RT or IT

B RR IO 

C TO PL

D RO IP

E TR II

F RP IC

G RI IA

H RC IL

I TC PA

J RA CT

K RL CR

L OT IR

M OR CO

N OO CP

O OP PI

P OI PC

Q OC CI

R TI PP

S TT CC

T TA PO

U TP CA

V OA CL

W OL AT

X PT AR

Y TL AO

Z PR AP

1 A1

2 AC

3 AA

4 AL

5 LT

6 LR

7 LO

8 LP

9 LI

0 LC

. LA

& LL

As an example, let's encode the following messazge:

ARRIVING 1530 HRS. CODE NAME SCOTT RODGERS

RT TI PP TC OA PA OO IA AI LT AA LC RC PP TT LA TO PI RO TR CP IT OR II CC PL OP TA PO TI PI IP RI TR PP TT

The final step is a columnar transposition using a keyword:

M

E

X

I

C

O

4

2

6

3

1

5

R

T

T

I

P

P

T

C

O

A

P

A

O

O

I

A

A

I

L

T

A

A

L

C

R

C

P

P

T

T

L

A

6

6

8

3

The numbers 6683 have been added as nulls in order to fill empty spaces and the vertical columns are now read horizontally in numerical order, and our encrypted message is:

PPALT 8TCOT CAIAA P6RTO LRLPA ICT3T OIAP6

To decrypt simply reverse the above steps.

Any key of 8 characters can be used, including words with double letters using upper and lower case letters.

For the numerically inclined a sequence of eight numbers could just as easily be used.



II: Homophonic Cipher (1)

Homophonic ciphers consist of more than one substtitution fo each character. In this version there are 25 letters in the alphabet. Using a key word the letters are numbered, starting with 00 under the first letter of the keyword, 01 under the second letter and so on up to '99.' When finished, each letter can be encrypted by one of four possibilities.

However in the example below I have added another twist: the alphabet is numbered in base 16. The keyword is numbers.Starting with the letter N the sequence begins with 00, U/V is 01, etc.

A

B

C

D

E

F

G

H

I

J

K

L

M

1c

03

1d

1e

04

1f

20

21

22

23

24

25

02

2e

0a

2f

30

0b

31

32

33

34

35

36

37

09

40

11

41

42

12

43

44

45

46

47

48

49

10

52

18

53

54

19

55

56

57

58

59

5a

5b

1

N

O

P

Q

R

S

T

U/V

W

X

Y

Z

00

26

22

28

05

06

29

01

2a

23

26

2d

07

38

39

3a

0c

0d

3b

08

3c

3d

3e

3f

0e

4a

4b

4c

13

14

4d

0f

4e

4f

50

51

15

5c

5d

5e

1a

1b

5f

16

60

61

62

63

Meet me in parking lot behind cafe

02 0b 12 5f 38 0b 22 07 4b 1c 05 36 22 00 44 25 26 3b 03 04 57 22 0e 54 1d 40 1f 19

The encryption is again finished with a columnar transposition, in this case using the keyword NUMBERS:

N

U

M

B

E

R

S

4

7

3

1

2

5

6

0

2

0

b

1

2

5

f

3

8

0

b

2

2

0

7

4

b

1

c

0

5

3

6

2

2

0

0

4

4

2

5

2

6

3

b

0

3

0

4

5

7

2

2

0

c

5

4

1

d

4

0

1

f

1

9

6

4

4

5

 

 

 



'6445' has been added to make the message 60 characters long thus making it easy to divide the message into groups of five characters.

The final message:

b0b25 0e151 b1224 5f 084 62300 40f05 4b2d6 22c00 54152 00371 92373 40244

To decipher the transposition, count the number of characters in the message and divide by the number

of characters in the keyword; the result will be the number of columns in the transposition.


III Homophonic Cipher (2)

This cipher uses a matrix consisting of three alphabets, the digits 1-0 twice, a period and an ampersand, along with ten characters that are used as the cipher text.


W

A

L

T

D

I

S

N

E

Y

W

T

U

R

K

E

Y

A

B

C

D

A

F

G

H

I

J

L

M

N

O

P

L

Q

S

V

W

X

Z

0

1

2

3

T

4

5

6

7

8

9

.

&

S

A

D

N

D

W

I

C

H

B

E

F

G

I

J

K

L

M

O

P

Q

R

T

U

S

V

X

Y

Z

1

2

3

4

5

6

N

7

8

9

0

T

U

N

A

F

I

E

S

H

B

C

D

E

G

J

K

L

Y

M

O

P

Q

R

V

W

X

Y

Z



Thus the letter A can be encrypted as either WS, TY, or NN. As a final step a transposition should be used for added security.


IV: Bifid Cipher

This cipher uses a 6x6 square, with a keyed alphabet and the digits 1-0. The first ten letters are followed by the numbers, that is A1 B2 C3....J0. The rows and columns are numbered 1-6.

The following example uses the keyword SECURITY:

 

1

2

3

4

5

6

1

S

E

5

C

3

U

2

R

I

9

T

Y

A

3

1

B

2

D

4

F

4

6

G

7

H

8

J

5

0

K

L

M

N

O

6

P

Q

V

W

X

Z

The message is written using the numbers at the top and side, written in columns under each other:

Make contact   with   agent 007  at  1100 hrs
5251 1552212 6224 24152 554 22 3355 421
4622 4654644 4244 62254 113 64 1111 411

These numbers are then read off horizontally encrypting the message with the resulting letters
52 51 15 52 21 26 22 42 41 52 55 42 23 35 54 21 46 22 46 54 64 44 24 46 22 54 11 36 41 11 14 11
K   0    3 K   I   A    I  G   6   K N   G  9  4   M  R   J   I    J   M W  H  T   J   I   M   S   F  6   S   C  S

K03KI AIG6K NG94M RJIJM WHTJI MSF6S CS265 (with the random numbers 265 added to give the five-character spacing.)

Notice this cipher not only encrypts letters and numbers, but sometimes encrypts letters and numbers as numbers.