Changes

'''Cryptography''' is the writing of [[secret]]s. The word 'cryptography' comes from the [[Greek]] 'cryptos', secret, and 'graphos', writing.

'''Cryptography''' is the writing of [[secret]]s. The word 'cryptography' comes from the [[Greek]] 'cryptos', secret, and 'graphos', writing.

== Codes ==

== Codes ==

[[Code]]s are, in their simplest terms, replacing words and phrases in a message with other words and phrases whose meaning is known to the recipient. For example:

In its simplest term, a [[Code|code]] is the replacement of a [[Plaintext|message]] with an [[Ciphertext|alternative message]] whose meaning is known to the recipient. For example:

Take the phrase: "The bombers require a fighter escort at Newcastle, 2300 hours"

Take the phrase: "The bombers require a fighter escort at Newcastle, 2300 hours"

There are many ways to encode this. Some appropriate rules must be created and shared with the recipient. Because to anyone who intercepts the message, something that sounds like a code could arouse their suspicions, causing the message to be "cracked" (decoded) or to be destroyed or otherwise delayed. Therefore it is wise to create a code that produces innocent sounding messages:

There are many ways to encode this. For example, both the sender and the recipient could agree on appropriate rules to encode that message. Ideally, these rules would create a [[Ciphertext|ciphertext]] that would not arouse the suspicions of an intruder intercepting the message.  Otherwise, the message could be decoded, destroyed, or otherwise delayed. "cracked" (decoded) or to be destroyed or otherwise delayed.

:11.00pm, Newcastle: Mother birds look for duckling flock

:11.00pm, Newcastle: Mother birds look for duckling flock