Problem - Kevin Tafuro

parison to standard modes. As of this writing, there are three free, publicly available
implementations of CCM mode:
• The reference implementation: http://hifn.com/support/ccm.htm
• The implementation from Secure Software: http://www.securesoftware.com/ccm.php
• The implementation from Brian Gladman: http://fp.gladman.plus.com/AES/ccm.zip
See Also
• CCM reference implementation: http://hifn.com/support/ccm.htm
• CCM implementation from Secure Software: http://www.securesoftware.com/
ccm.php
• CCM implementation from Brian Gladman: http://fp.gladman.plus.com/AES/
ccm.zip
• CWC home page: http://www.zork.org/cwc/
• OCB home page: http://www.cs.ucdavis.edu/~rogaway/ocb/
• Recipes 4.9, 4.11, 5.5-5.10, 5.14, 5.16
5.5 Using a Raw Block Cipher
Problem
You’re trying to make one of our implementations for other block cipher modes
work. They all use raw encryption operations as a foundation, and you would like to
understand how to plug in third-party implementations.
Solution
Raw operations on block ciphers consist of three operations: key setup, encryption of
a block, and decryption of a block. In other recipes, we provide three macros that
you need to implement to use our code. In the discussion for this recipe, we’ll look at
several desirable bindings for these macros.
Discussion
Do not use raw encryption operations in your own designs! Such operations
should only be used as a fundamental building block by skilled
cryptographers.
Raw block ciphers operate on fixed-size chunks of data. That size is called the block
size. The input and output are of this same fixed length. A block cipher also requires
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