I was doing some research for a project last week and made a note of a new package DBMS_SQLHASH that some sites are marking as new for 11G but it's also there in 10gR2. This is an interesting package that allows the use of cryptographic hashes such as HASH_MD4, HASH_MD5, or HASH_SH1 (From DBMS_CRYPTO) to hash the result set of a SQL statement to allow the checking of data integrity. This allows data to be checked to see if it has been changed. The package with the function GETHASH can also be used to test the integrity of dictionary objects in a similar fashion to some of the commercial database scanners that are available. The package can of course be used to select the source of packages, triggers, views and more and hashes can be calculated and stored for later comparison.
Finally Lazslo sent me an interesting link to the methods Elcomsoft are using to make password crackers run at 20 times the normal speed by passing off the repetitive calculations to the parallel hardware available in graphics cards such as NVIDIA GeForce8 graphics boards. The page is titled "Elcomsoft Distributed Password Recovery"