# Gavin Andresen
# 2010-10-01 16:50:41
# https://bitcointalk.org/index.php?topic=1330.msg14866#msg14866

A half-baked thought that's been bouncing around my head for the last couple of days: @p{par}

One piece of functionality missing from bitcoin is the ability for somebody to prove that they own a certain bitcoin address. @p{par}

I'm thinking that if there was a way to ask bitcoin to: @p{brk}
  1) Sign an arbitrary bunch of data with a bitcoin address' private key, and return the signature. @p{brk}
  2) Take a bitcoin address and signed data and verify that the signature is valid. @p{par}

... then maybe that could function as the building block allowing webs of trust to develop in an application independent of 'core bitcoin'. @p{par}

And secure, pseudo-anonymous communication between people who know only each other's bitcoin addresses.  And probably a bunch of other interesting things I haven't thought of. @p{brk}