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
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
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