The "make menuconfig" help text for CONFIG_DM_CRYPT points to http://www.saout.de/misc/dm-crypt/ for further info...

> Information on how to use dm-crypt can be found on
>
> <http://www.saout.de/misc/dm-crypt/>

...but that site says...

> Note: This page is horribly out of date.
> You can find the current pages for the dm-crypt project (the Linux
> kernel part) here: http://code.google.com/p/cryptsetup/wiki/DMCrypt
> and the project page for the command line tool cryptsetup (with Linux
> Unified Key Setup - LUKS) here: http://code.google.com/p/cryptsetup/


Suggested solution; change help-text link(s) to point to http://code.google.com/p/cryptsetup/wiki/DMCrypt and to http://code.google.com/p/cryptsetup/