Pay to Script Hash.

Lets a sender pay to a short code standing for the receiver's spending rules, however complex those rules are.

Pay-to-script-hash moves the job of setting spending rules, such as needing several signatures, from the sender to the receiver. The sender only needs a short, fixed-length code that is easy to scan from a QR code or copy and paste. Miners showed their support by marking the blocks they mined, and the new rules applied to blocks from 1 April 2012.