Difference between revisions of "OCB"
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| − | OCB is the Offset Code Book mode. | + | OCB is the Offset Code Book mode. The mode provides an efficient form authenticated encryption with additional data, which is commonly referred to an AEAD scheme. OCB mode is efficient because blocks of data are visited once to generate the cipher text and create the authentication tag. In contrast, modes like CCM, EAX and GCM visit the block of data twice - once to encrypt the data and once to create the authentication tag due to patent encumbrances. For more information, see Dr. David Wagner's comparison of AEAD schemes at [http://www.cryptopp.com/w/images/9/99/AEAD-Comparison.ppt.zip AEAD Comparison]. |
| − | This mode has been patented by Prof Phil Rogaway and licensed to OpenSSL with the | + | This mode has been patented by Prof Phil Rogaway and licensed to OpenSSL with the license grant available [[Media:OCB-patent-grant-OpenSSL.pdf|here]]. Dr. Rogawy's paper can be found at [http://www.cs.ucdavis.edu/~rogaway/papers/ad.pdf Authenticated-Encryption with Associated-Data]. |
Revision as of 21:06, 25 November 2013
OCB is the Offset Code Book mode. The mode provides an efficient form authenticated encryption with additional data, which is commonly referred to an AEAD scheme. OCB mode is efficient because blocks of data are visited once to generate the cipher text and create the authentication tag. In contrast, modes like CCM, EAX and GCM visit the block of data twice - once to encrypt the data and once to create the authentication tag due to patent encumbrances. For more information, see Dr. David Wagner's comparison of AEAD schemes at AEAD Comparison.
This mode has been patented by Prof Phil Rogaway and licensed to OpenSSL with the license grant available here. Dr. Rogawy's paper can be found at Authenticated-Encryption with Associated-Data.
