Chris Christensen

Northern Kentucky University

Jack Levine’s Cipher

The Hill Cipher 1929

Lester S. Hill1890 - 1961

Simple Substitution

Substitution CiphersDigraphic Substitution

Plaintext cipherCiphertextMVHQLU

Plaintext mis sis sip pik

CiphertextBQT SEI AEP YFC

Hill Cipher

m11 0 3 13 23 B9 22 0 18 i 19 Q mod26

s T6 7 11 12 24

Jack Levine (1907 – 2005)

“Solving Cipher Secrets”

2 October 1926

Flynn’s Weekly

13 November 1926

Jack Levine’s Cipher

Jack Levine’s Cipher

Plaintext comehere

stayaway

Two Plaintext Messages

Ciphertext

Enciphering Key

Jack Levine’s Cipher

Deciphering Key

Add Consecutive Numbers

1 12 2

1 12 2

1 12 2

30 1024 5 20 19c mo

17 1628 3 27 4e eh

22 21 28 3er

Subtract Consecutive Numbers

1 12 2

1 12 2

1 12 2

30 1024 5 20 19s at

17 1628 3 27 4y wa

22 21 28 3ya

ACA

Levine and Cryptography

24 July 1989 Letter to Louis Kruh

Enciphering Key

Three Messages

Deciphering Key

0 1 2 1 21 2 0 1 21 2 1 2 0

1 1 11 1 11 1 1

Ciphertext

19 27 2 39 2 3 6 8 10 11 20

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 26

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

Lester Hill’s Cipher

Is a true block cipher. Blends two messages together.

Can encipher a true and false message and, if forced to reveal “the message,” choose to reveal the false message.

Comparison

Jack Levine’s Cipher

THEDEPARTMENTOFMATHEMATICSA

TNORTHERNKENTUCKYUNIVERSITY

Another way

33 13 21 13 16 15 45 2 17 2 51 2 29 2 49 2 11 2