$Id: ToDo,v 1.24 2001/08/09 19:12:05 btrott Exp $

Crypt::OpenPGP todo
--------
xx * Crypt::OpenPGP main USAGE docs
xx * docs (for other classes)
* support for CAST5, ElGamal signing
xx * clear text signatures; need to make text into canonical text for
     signing
xx * more support for looking up keys in keyring (eg. look up userid, etc.)
xx * encrypt and sign/decrypt and verify
* caching in find_keyblock. let caller pass in 'marker' code-ref that, given
  a packet, returns a unique 'marker' to point to that keyblock. eg. lookup
  by keyid returns the certificate keyid, lookup by userid returns the
  userid, etc. then, two levels of caching: 1) store offsets of keyblocks
  by marker; 2) store already-parsed keyblocks by marker. we could let the
  calling function do the latter, of course, ie. find_keyblock_by_keyid
  would manage a hash of keyids => keyblocks. also: when reading a keyblock
  (after already finding the start offset), maybe don't parse SECRET_KEY
  and PUBLIC_KEY packets? since we already have the start cert there is
  no use in parsing the next one we come to, because that indicates the
  start of a new keyblock.
* add KeyRing::find_keyblock_by_index; given index, return that keyblock.
  also allow negative indices. create map of keyring on KeyRing::init.
xx * KeyBlock needs some methods to "do stuff" with the keyblock contents;
    for example, there should be a method to return: 1) the master key;
    2) a key given a key ID; 3) the key to be used for encryption, and the
    key to be used for signing.
xx * KeyRing::find_keyblock_by_keyid should no longer return certificate if
    called in list context. Instead it should just return a list of all
    matching keys if called in list context, first match otherwise. Caller
    should use KeyBlock methods to get actual certificate.
* KeyRing support multiple keyrings so that lookups occur over multiple
  rings.
xx * compatibility param to encrypt and sign (and keygen, maybe), eg.
     Compat => 'PGP2' turns on Version => 3 and Cipher => 'IDEA'
* smart detection and description of arbitrary files, eg. pass in some
  data and give back 'RSA signed message, Version 3, probably PGP2'
xx * compressed packets
xx * symmetrically-encrypted encrypted data packets
* subkey generation
* add PGPWords from Mike Dillon; probably should add an interface to this
  through Certificate? ie. $cert->word_fingerprint, which would take
  $cert->fingerprint and run it through the Words module.
xx * encrypted MDC packets
xx * make find_keyblock_by_keyid work with subkeys
xx * key generation, secret certificate saving and encrypting
xx * Crypt::OpenPGP high-level DWIM interface
xx * support for armouring
xx * support for writing packets (v4 fingerprints/key IDs will come with this)
* keyblock merging keys, signatures, user IDs
xx * implement a KeyRing::find method that looks only for specific key IDs, etc.
xx * generate fingerprint on cert while reading in (in 'parse'); that way we
     don't have to reserialize
* test suite: tests for: compressed signatures, compressed encrypted data
  packets, more versions of PGP, more pkalgs, subpackets
* improve subpacket system: constants for types, better integration into
  signatures, etc.
xx * better installation: determine prereqs based on answers to prompts
     about preferred ciphers, pk systems, etc.
* use key flags to determine "what a key can do" (ie. signing, encryption)
xx * support writing v4 packet headers
* add some example scripts
* improve CRC24 implementation by using C implementation. problem:
  String::CRC does not work for me (doesn't accept init, for one thing).
