Hey, sorry for being annoying, but what is Adamant's stance on metadata? For now, while the message itself is encrypted, it is very visible which addresses interact with each other. Are there plans to change this in the future?
We've thought about it, yes.
It could be possible to have a type of "super-stealth message", where it is visible that a message was sent, but not to whom.
It is one of alternatives.
The system would be quite simple: omit the receiving address completely. The receive will download all new blocks and just go through all transaction, trying to decrypt them. If they have the private key, they will be able to successfully decrypt the message addressed at them, if not, nothing happens.
This would solve quite a few problems:
- Someone watching traffic and the blockchain can only see that an address sent a message, but not to whom.
- Since the receiving party is forced to download complete blocks*, a spy cannot conclusively link sender and receiver together.
*Of course, this has it's holes as well. For example, if I watch an entity downloading blocks and they suddenly stop, I can safely assume that the message directed at them was in the last few blocks. This problem is amplified by Adamants extremely short block times, especially when few people are using the system.
One solution would be to have the clients always sync completely, no matter what, but this could still make correlations visible.
Another solution could be to have dedicated "super-stealth blocks", meaning, "super-stealth-messages" are collected over a certain time and are written in a block that occurs every few hours, or maybe even only once a day. After all, the bigger the pool of messages, the harder it is to link two entities. This solution would obviously hve the problem, that an attacker could fill the super-stealth blocks in a way, that all but a few messages in the block belong to them. The few remaining can be correlated to the receiver, if they only download up to a certain block height.
Still, I think decoupling theye parts, somewhat making the metadate as inconclusive as possible is important for a good privacy focussed messenger.
ADAMANT is the first one real blockchain messenger. So what we did it testes the concept.
All the sweets will be later.
