Anyone-Can-Pay(also known as ACP) wast first proposed as a lock, and as the community grew, the ACP gradually became a feature or a mode, there are many locks that support the features of ACP, e.g. PW lock, UniPass, and Omnilock.
Here we focus on Omnilock, unlike other locks, Omnilock providers ACP feature as a flag, which means that the user can choose whether or not to enable the ACP feature, and Omnilock's ownership is also optional, Omnilock provides the P2SH authentication mode.
