!!! Overview
[{$pagename}] is a method of [Encryption] by which units of [plaintext] are replaced with [ciphertext] according to a fixed system; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. [{$pagename}] keeps the the units of the [message] are retained in the same sequence in the [ciphertext], but the units themselves are altered.

[Decryption] the text by performing the inverse substitution.

[{$pagename}] can be compared with [Transposition Ciphers] where the units of the [plaintext] [message] are rearranged in a different and usually quite complex order, but the units themselves are left unchanged.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]