status

needs testing.  really could use the opinion on the crypto from
someone with more experience in this area.  haven't done performance
tests.

intro

this is cryptfile, an encrypted block file served over styx.
for more information, see the manual page, cryptfile(4).

download

see http://www.ueber.net/code/r/cryptfile for instructions.

install

change the "mkconfig" if you don't have $ROOT set.  now "mk" to
compile and "mk install" to install the files.

when building from within inferno, insert SYSHOST=Inferno and ROOT=
in the mk invocations to override the values in the mkconfig.

licence & author

this code is in the public domain, written by mechiel lukkien,
reachable at mechiel@ueber.net.

todo:

• after a "forget" the user enters a password.  if it is wrong, the
  styx read/write on the file fails.  this might upset file servers
  such as kfs much.  perhaps it is better not to respond to the styx
  request until the user enters a correct password.
  

• add option to change the password (but keep the key of course).
  involves making a new salt, deriving a new key, making a new iv and
  making a new crypted data (with new random cookie, the same key and
  the calculated sha1).