Automatic checkpointing with autocheck Masternode added on EKN code.
Masternode for autocheckpoints offers another layer of security in Elektron network make it unvulnerable to fake chain attacks and malicious node submissions.
Get ready, launch is coming next.
When you use the word "Masternode" are you referring to Darkcoin-style Masternodes?
Basically yes. Our masternodes for ACP instead of mixing coins as the darkcoin network ones function as main blockchain checkpoint genesis sites.
Technology behind ACP is already explained in the OP, please have a read about that.
Our development roadmap has already an anon mixing coins masternodes system addition to EKN scheduled, so we'll be using a similar technique as the darkcoin one with similar functionalities also.