Enable caching of key-derived context info such as key schedules from

one encryption operation to another.  Use a new function in the
enc_provider structure for cleanup.  Implement caching of aes_ctx
values.

Using Greg's performance tests from the derived-key caching work, on a
2.8GHz Xeon, I see 1 million AES-128 encryptions of 16 bytes improved
by 5-6%; encryptions of 1024 bytes and checksums are not significantly
affected.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@23574 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 12 insertions, 0 deletions

diff --git a/src/include/k5-int.h b/src/include/k5-int.h
index 2a4f1d8191..8a37e08e10 100644
--- a/src/include/k5-int.h
+++ b/src/include/k5-int.h
@@ -640,6 +640,16 @@ struct krb5_key_st {
     krb5_keyblock keyblock;
     int refcount;
     struct derived_key *derived;
+    /*
+     * Cache of data private to the cipher implementation, which we
+     * don't want to have to recompute for every operation.  This may
+     * include key schedules, iteration counts, etc.
+     *
+     * The cipher implementation is responsible for setting this up
+     * whenever needed, and the enc_provider key_cleanup method must
+     * then be provided to dispose of it.
+     */
+    void *cache;
 };
 
 /* new encryption provider api */
@@ -668,6 +678,8 @@ struct krb5_enc_provider {
                                   krb5_data *out_state);
     krb5_error_code (*free_state)(krb5_data *state);
 
+    /* May be NULL if there is no key-derived data cached.  */
+    void (*key_cleanup)(krb5_key key);
 };
 
 struct krb5_hash_provider {