Does anybody know how to do M of N decryption using the crypto tools commonly seen in Nostr clients? Is it even possible?
We want to find a way to do a 1 of 10000 decryption scheme so that instead of signing group messages to each user, we sign to a batch of users at a time, reducing the noise in the network.
Ideas?
#asknostr
This may work by sending one event to all group members
"tags": [
["p", "B's pubkey"],
["m", "userA pubkey",
["m", "userB pubkey",
["m", "userC pubkey",
...
]
I was hoping to do it without identifying each individual receiver.
The only m of n I know of is Shamir. Though you'd have to find an implementation that uses GF(2^16).
Naive simple idea:
1. Create one group key pair
2. Exchange the key pair with all group participants.
3. Let clients listen for this group public key
Pro:
- simple protocol
- better anonymity
Con:
- no forward secrecy
- initial noise on group creation
Too risky. The new key pair can leak without leaking the user's main key. Any disagreement in a group can expose the entire history of the group.
I‘m visiting Threema next Thursday. Tell me if you would like to be hooked up with someone.
Who is Threema?
The messenger company: https://threema.ch
Cool! If it is permitted to ask: Why are you going?
I‘ll bring the now bottled beer we brewed together on a company event.
Awesome! A colleague of mine is also brewing quite actively https://www.bunthaus.beer/die-biere/
Gose Morning Vietnam 🤣
If the group has its own key pair and every member knows the private key, it is simple. Of course, every approach has downsides.
