Or you could send encrypted texts with a subject line that tells how many leading zero bits are in your GPG private key. Perhaps start with keysize - 1. Then f

Or you could send encrypted texts with a subject line that tells how many leading zero bits are in your GPG private key. Perhaps start with keysize - 1. Then for each new message subtract 1 from the number of leading zeros. Now at some point Eve has to decide for herself when it's no longer worth it to brute force your messages. Edit: clarification