!!! Overview
In [cryptography], a [{$pagename}] is a deterministic algorithm operating on fixed-length groups of bits, called [Block], with an unvarying transformation that is specified by a [Symmetric Key]. 

[{$pagename}] are important [Cryptographic Primitive] components in the design of many cryptographic protocols, and are widely used to implement [encryption] of bulk data.

!! [Block cipher mode of operation|Block Cipher Mode]
There are several different [Block cipher mode of operation|Block Cipher Mode] that are used.

[{$pagename}] operate on large blocks of digits with a fixed, unvarying transformation. This distinction is not always clear-cut: in some modes of operation, a [{$pagename}] primitive is used in such a way that it acts effectively as a [Stream Cipher]. 

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Block cipher|Wikipedia:Block_cipher|target='_blank'] - based on information obtained 2015-12-07