Monitoring Times challenge

Monitoring Times Challenge

Contents

Monitoring Times challenge
One-time Pad software

My article in the October, 1998, issue of Monitoring Times magazine contained a challenge at the end asking readers to solve a one-time pad encrypted message.

Given the encrypted message

BABPFQHWZGIRPFNWBCOS

and the key

LISTENING AND LEARNING

what is the plaintext message?

The article specifies the letter-to-number mapping of

A 1

B 2

C 3

... ...

Z 26

So the encrypted message can be represented by the string of numbers

02 01 02 16 06 17 08 23 26 07 09 18 16 06 14 23 02 03 15 19

and the key as

12 09 19 20 05 14 09 14 07 01 14 04 12 05 01 18 14 09 14 07

Click here for the answer.

ONE-TIME PAD SOFTWARE

If you're interested in a simple program that might help, I wrote a short program to do the letter-to-number translation and the one-time pad encryption and decryption.

Click here for the C language source code and/or here for a DOS executable.

To encrypt the message MONITORING TIMES with the key SECRET LISTENERS type in the following

OTP "MONITORING TIMES" "SECRET LISTENERS"

and you should see the output

Message: MONITORING TIMES
(15)     13 15 14 09 20 15 18 09 14 07 20 09 13 05 19 
Key:     SECRET LISTENERS
(15)     19 05 03 18 05 20 12 09 19 20 05 14 05 18 19 
Result:  FTQAYIDRGAYWRWL
(15)     06 20 17 01 25 09 04 18 07 01 25 23 18 23 12

To decode the message, type in

OTP -d FTQAYIDRGAYWRWL "SECRET LISTENERS"

and you should see the output

Message: FTQAYIDRGAYWRWL
(15)     06 20 17 01 25 09 04 18 07 01 25 23 18 23 12 
Key:     SECRET LISTENERS
(15)     19 05 03 18 05 20 12 09 19 20 05 14 05 18 19 
Result:  MONITORINGTIMES
(15)     13 15 14 09 20 15 18 09 14 07 20 09 13 05 19

Comments to Dan Veeneman
Last revised August 25, 1998