Request for Review: AESCrypt.init performance JDK change (original) (raw)

Alan Bateman Alan.Bateman at oracle.com
Tue Jul 17 08:00:23 UTC 2012

On 16/07/2012 21:08, Deneau, Tom wrote:

Please review the following webrev which improves performance for the com/sun/crypto/provider when the algorithm is AES for some kinds of Cipher usage patterns.

http://cr.openjdk.java.net/~tdeneau/aescrypt-init-performance/webrev.01/ I do not have a bug number for this change but a description would be something like the following: Consider an application which holds on to a Cipher object for AES and keeps the same key but calls Cipher.init to change the Cipher between encryption and decryption. The current code in AESCrypt.java recomputes the expanded key (which is an expensive operation) with each call to init. The proposed code saves the key and, if it has not changed, does not need to recompute on subsequent calls to Cipher.init. The proposed code also incorporates into the key calculation the final step which was the expansion of the key to a 1-dimensional array of ints. This step used to be done in the routine setSubKey. -- Tom Deneau Tom - I assume this will need to get reviewed for jdk8 and bake in that forest for a bit before it can be considered for 7u.

-Alan.

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