in app (Java) crypt "file store"/ media cache ?

[jamesd at echeque.com]

> On Mon, Jul 06, 2020 at 11:15:01PM +0000, таракан wrote:
>> I develop an embedded system for a secure communication station.
>> I want everything to stays transient, to be erased as soon and as fast as possible.

The authorities are more interested in the metadata, who is
communicating with whom.  To reduce the value of this information, needs
to be embedded in a flood of unimportant chats.

On 2020-07-07 11:55, Zenaan Harkness wrote:
> This distributed/decentral content is interesting - I've been thinking of "cache" as the local node's "contribution" to the distributed P2P content store.

The strong cure for revealing metadata is to embed private
communications in a pool of everyone to everyone public communications.

Suppose everyone interested in signing or encrypting their tests in this
pool as a Zooko identity.

Encrypted messages are dumped into the pool with everything else, and
downloaded by everyone, but if he does not have a key that can decrypt
an encrypted message, his client does not show him that message.

Let S be curve25519 public key of the sender, R the public key of the
recipient, r and s the corresponding private keys.

The message starts with S.  It is encrypted using the symmetric key s*R.

The recipient client software tries the symmetric key r*S, which, if the
message is for him rather than someone else, is going to equal s*R.  If
it does not work, obviously for someone else.