previous |
start |
next
Transposition Ciphers
In this system, the order of the plaintext
characters is changed, but the characters themselves are not - that
is, the encrypted message contains all the same characters as the
plaintext. For example, a simple columnar cipher
could be constructed thus:
Hence, the ciphertext is:
eatitnihmexnetmgmedt
Neither substitution nor transposition ciphers are regarded as
secure for any serious use. The modern approach is to use basically
the same ideas as these, but with much more complex algorithms (see
DES, later).
previous |
start |
next