* Decrypt content with key x, publish as kind 1337
* When content receives zap, send "DM" to zapper with x with kind 1338
* Zapper decrypts content
* Decrypt content with key x, publish as kind 1337
* When content receives zap, send "DM" to zapper with x with kind 1338
* Zapper decrypts content
Kind 1337 would have a decrypted tag and an plaintext Tag as a teaser, and a tag for the price for the decryption key.