Lines Matching refs:ocb
1330 \subsection{OCB Mode}
1331 LibTomCrypt provides support for a mode called OCB\footnote{See
1332 P. Rogaway, M. Bellare, J. Black, T. Krovetz, \textit{OCB: A Block Cipher Mode of Operation for Efficient Authenticated Encryption}.}
1333 . OCB is an encryption protocol that simultaneously provides authentication. It is slightly faster to use than EAX mode
1334 but is less flexible. Let's review how to initialize an OCB context.
1336 \index{ocb\_init()}
1338 int ocb_init( ocb_state *ocb,
1345 This will initialize the \textit{ocb} context using cipher descriptor \textit{cipher}. It will use a \textit{key} of length \textit{keylen}
1352 \index{ocb\_encrypt()} \index{ocb\_decrypt()}
1354 int ocb_encrypt( ocb_state *ocb,
1358 int ocb_decrypt( ocb_state *ocb,
1365 both functions given a single \textit{ocb} state. For bi-directional communication you will have to initialize two \textit{ocb}
1372 \index{ocb\_done\_encrypt()}
1374 int ocb_done_encrypt( ocb_state *ocb,
1382 This will terminate an encrypt stream \textit{ocb}. If you have trailing bytes of plaintext that will not complete a block
1387 an input message equal to the length of the block size then you pass the data here (not to ocb\_encrypt()) only.
1391 \index{ocb\_done\_decrypt()}
1393 int ocb_done_decrypt( ocb_state *ocb,
1407 To make life simpler the following two functions are provided for memory bound OCB.
1409 %\index{ocb\_encrypt\_authenticate\_memory()}
1420 This will OCB encrypt the message \textit{pt} of length \textit{ptlen}, and store the ciphertext in \textit{ct}. The length \textit{ptlen}
1423 \index{ocb\_decrypt\_verify\_memory()}
1435 Similarly, this will OCB decrypt, and compare the internally computed tag against the tag provided. \textit{res} is set
1439 OCB mode,
1542 Galois counter mode is an IEEE proposal for authenticated encryption (also it is a planned NIST standard). Like EAX and OCB mode, it can be used in a streaming capacity
