* Implement 256 bit key Twofish.

  * clearsig: keep lineendings as they are. Remember that trailings
    blanks are not hashed.

  * Check revocation and expire stuff.	[I'm currently working on this.]

  * Check calculation of key validity. [I'm currently working on this.]

  * See why we always get this "Hmmm public key lost"

  * print a warning when a revoked/expired secret key is used.

  * remove more "Fixmes"

  * Use capabilities if available.  glibc2 does not support it yet?
    What about 2.2 or should we use the system calls directly?

  * when decryptiong multiple key: print a warning only if no usable pubkey
    encrypte package was found.  Extension: display a list of all recipients.

  * in pkclist.c : display info about the key before saying that
    we have (no) trust info.

  * for new key: the last keyring specified is used.  Order is: default
    keyrings, keyrings from options, keyrings from the command line.

  * display a kind of message-id from a signature (the timestamp may not
    be suffiecient but DSA signatures are always different).  This can
    be used to prevent replay attacks.	(something is mentioned in rfc2440).


Nice to have
------------
  * preferences of hash algorithms are not yet used.
  * new menu to delete signatures and list signature in menu
  * Replace the SIGUSR1 stuff by semaphores to avoid loss of a signal.
    or use POSIX.4 realtime signals.
  * add test cases for invalid data (scrambled armor or other random data)
  * add checking of armor trailers
  * Burn the buffers used by fopen(), or use read(2). Does this
    really make sense?
  * change the fake_data stuff to mpi_set_opaque
  * How about letting something like 'gpg --version -v', list the
    effective options. [Too much work.]
  * Stats about used random numbers.