Concepts in Data Encryption:
When performing a columnar transposition, a keyword is first needed. The message is
then written into rows beneath the keyword. The example message which we'll use will be
e n c r y p t 2 3 1 5 7 4 6 S E C R E T M E S S A G E S
Transpositions are often used as part of a more complex system. If a transposition is used in conjunction with a monoalphabetic substitution then the transposition as above may be solved, after having first worked out the plaintext letters of the substitution by looking at letter frequencies. Imagine the possibilities.
As with many cryptographic systems the greater the amount of ciphertext that is available, the easier the cipher is to solve. Transposition adds some security, however as with all cryptography, sometimes the solution is easier than one might be inclined to believe.
Copyright ©1999 ThinkQuest Team 27158 Developed for ThinkQuest 1999