-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 25/07/13 08:58, elijah wrote: > * Third-party-dropbox: To exchange messages, user A and user B > negotiate a unique "dropbox" URL for depositing messages, > potentially using a third party. To send a message, user A would > post the message to the "dropbox". To receive a message, user B > would regularly polls this URL to see if there are new messages.
Hi Elijah, I'm curious about the third-party dropbox idea (partly because I'm currently working on an HTTP dead drop transport for Briar). It seems like there are two ways you could do this: 1. The dropbox is shared by multiple users; when user A authenticates and deposits a message, she tells the dropbox that user B is allowed to collect the message. 2. The dropbox is only used by one pair of users; when user A authenticates and deposits a message, the dropbox knows it's for user B. In either case, the dropbox has metadata about who's communicating with whom. In case 2, anyone watching the dropbox also has that metadata. (In case 1, anyone watching the dropbox has that metadata unless communication with the dropbox is encrypted and padded.) So I don't see how this technique is metadata-resistant, except in the short term (NSA has to arrange metadata collection from a new service provider). What am I missing? Cheers, Michael -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEcBAEBAgAGBQJR8OLFAAoJEBEET9GfxSfMS18IAIyZb4uFSHh41i6dXgivVP/W m2N3WuRP3DUAnf846crXGhOyoJrYUqmiuiHFPZp7lQfnKkXai+/pyBjKbIgv0Q8T WPRfyqDRQ7mEc2mLdh5Z99afh4yEZRuPGyR2hZRwkDLha9CzKIHSlefCPNkU26c8 zJbWhJTifsynOoRvopp2on5nMcEHVxB09Q43g7B0yLxI+zzO5EUF8RbYx7Oj/25P RHIOPzx0cy7t3xF7OQUEAkA+lfh5roYWjGquJuxzMRGqdx1bzIwHo6PgBnC1uIP1 vRz+7di6LAduRicZAyQYNCbekrJezdxqqFqrTauAIiGTgGfkT0BqRZuw7hLwR5g= =H/+V -----END PGP SIGNATURE-----
