[Bitcoin-development] [BIP 15] Aliases

[theymos]

Bitcoin already has code and a protocol for transactions to IP
addresses. Why not reuse that for dynamic address lookup? Just a few
changes are necessary to enable complete user at server.com handling:
- Extend the protocol so that "reply" messages can be signed by a fixed
  public key
- Extend "checkorder" messages so they can specify an account to
  send BTC to. Or standardize on how to put the account into the
  message field.
- Enable DNS lookups for IP transactions. The DNS-only proposals could
  also be used here to avoid having to use the IP transaction protocol
  sometimes. The public key for signing "reply" messages can be gotten
  from TXT records. This will be safe with DNSSEC and Namecoin. With
  plain DNS Bitcoin could take a SSH-like approach and ask the user to
  verify the public key the first time it is used, remembering it later.

DoS attacks are already handled by the IP transactions code: the same IP
address is always given the same bitcoin address until it pays to that
bitcoin address.