path: root/include
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authorJoy Latten <latten@austin.ibm.com>2007-11-07 22:59:47 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-01-11 08:16:08 +1100
commit41fdab3dd385dde36caae60ed2df82aecb7a32f0 (patch)
treeaed4c4e7630cebc8b66d33fa6e26ec20f564bbd8 /include
parent[CRYPTO] camellia: De-unrolling (diff)
[CRYPTO] ctr: Add countersize
This patch adds countersize to CTR mode. The template is now ctr(algo,noncesize,ivsize,countersize). For example, ctr(aes,4,8,4) indicates the counterblock will be composed of a salt/nonce that is 4 bytes, an iv that is 8 bytes and the counter is 4 bytes. When noncesize + ivsize < blocksize, CTR initializes the last block - ivsize - noncesize portion of the block to zero. Otherwise the counter block is composed of the IV (and nonce if necessary). If noncesize + ivsize == blocksize, then this indicates that user is passing in entire counterblock. Thus countersize indicates the amount of bytes in counterblock to use as the counter for incrementing. CTR will increment counter portion by 1, and begin encryption with that value. Note that CTR assumes the counter portion of the block that will be incremented is stored in big endian. Signed-off-by: Joy Latten <latten@austin.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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