There are a couple of important differences, though someone from Signal might need to correct me if I get this wrong: - Signal never deletes keys until after a

There are a couple of important differences, though someone from Signal might need to correct me if I get this wrong: - Signal never deletes keys until after a message is read, because the key schedule and the message history are closely integrated. So if I send a "30 seconds" disappearing message, but you read it a month later, that will work. Keybase doesn't work that way; we delete keys on a fixed schedule, generally about a week. The "start the clock after sending" rule fits our key schedule better, without creating confusing cases at the one week boundary. - Keybase is designed to support "very large" groups, like thousands of people. In that setting, a "start the clock after reading" rule would be a problem. It's unrealistic that all N thousand members will ever read a given message, and that would make deletion less reliable.