As promised, dropped in the new librijndael. Benchmarks say about 3 times faster, but more performance testing will be done.
# Used for testing mod_rewrite.
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.*) install.php?do=modrewrite_test&str=$1
</IfModule>