The broader impact/commercial impact of this proposal is to reduce fraud in telecommunications. Americans received approximately 26 billion so-called "robocalls" last year, and in March 2019, a new monthly record of 5 billion robocalls was reached, according to the FCC. The Federal Trade Commission (FTC) reports the agency is on pace to receive 5+ million complaints about robocalls in 2019, a 30% increase over 2018. Robocalling scammers rely on relatively cheap technology that works on a large scale, and new schemes are getting smarter and pose a growing threat. Significantly, robocallers leverage artificial intelligence (A.I.), synthesized voice (so-called "deep fakes"), and caller ID spoofing, creating fraud of over $22 billion annually. This proposed project will work to reduce robocalls and associated fraud by filtering at the telecommunications device level. The proposed innovation leverages new decentralized ledger technology with blockchain encryption, real-time parsing of records, and real-time machine algorithms to block robocalls and reduce connection delays. The goal of the proposed innovation is to dramatically reduce the volume of fraudulent phone calls. This SBIR proposal focuses on filtering at the device level; initially applied to prevent robocalls, but potentially relevant for other secure applications. The innovation leverages blockchain's shared storage and memory, ability to operate in a "trustless environment" (due to lack of cross-telecom network collaboration on centralized robocall lists), as well as advances in blockchain encryption, artificial intelligence and machine learning, and real-time parsing of records and machine algorithms to block robocalls and reduce connection delays. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.