!!! Overview[1] [2]
[{$pagename}] is the process of encoding [Messages] or [data] in such a way that only [authorized|authorization] parties have [access].


[{$pagename}] provides [Confidentiality] of the [data] within a provided [context]


In [{$pagename}], a [Cipher] is applied to a [Message] which results in the encrypted [Ciphertext]

In an [{$pagename}] scheme, the [Message] or information, referred to as plaintext, is encrypted using a [Cipher], generating [Ciphertext] that can only be read if [decrypted|decryption].

For technical reasons, an [Encryption] scheme usually uses a [pseudorandom number generator] by an algorithm. 

Although it is possible to [decrypt|decryption] the message without possessing the key, the process requires large computational resources and large time frames which make the [decryption] impractical. 

An authorized recipient ([Bob]) can easily decrypt the message with the key provided by the originator ([Alice]) to recipients, but not to [unauthorized] interceptors ([Eve])


!! [Alice And Bob]'s Problem
This is a [User Story] where [Alice] wants to send [Bob] a message and [Eve] is [eavesdropping|Eavesdropper] in the [Communication]. This is why there is [Encryption].

[{Image src='/images/encryption.png' caption='encryption' align ='left' style='font-size: 120%;'}]

Where:
* m = [message] in [Plaintext]
* c = [Ciphertext]
* K%%sub e%% = [Key]
* E(K%%sub e%%, m) is the [Encryption] [Algorithm]
* D(K%%sub e%%, c) is the [Decryption] [Algorithm] 

[Bob] needs two things to decrypt the [Ciphertext]:
* [Key] and
* [Decryption] [Algorithm]


!! Types Of [{$pagename}]
There are two primary types of [{$pagename}]:
* [Symmetric Key Cryptography]
* [Asymmetric Key Cryptography]

!! [Encryption Scheme]
An [Encryption Scheme] is defined for [{$pagename}] [{$pagename}] operations.


!! [Information security]
[{$pagename}], by itself, can protect the [confidentiality] of [data], but other techniques are still needed to protect the [integrity] and [Non-Repudiation] of a [data].
For [Example] verification might be performed by using of a [Message Authentication Code] ([MAC]) or a [Digital Signature].


!! [{$pagename}] [Context]
A [Cipher] that like [Caesar Cipher] may have worked in Caesar's time but offers no [Security] with today's tools.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Encryption|Wikipedia:Encryption|target='_blank'] - based on information obtained 2013-04-10
* [#2] - [Cryptography Engineering: Design Principles and Practical Applications|https://www.amazon.com/Cryptography-Engineering-Principles-Practical-Applications/dp/0470474246/|target='_blank'] - based on information obtained 2013-04-10