Publication Date

Spring 2019

Degree Type

Master's Project

Degree Name

Master of Science (MS)


Computer Science

First Advisor

Thomas Austin

Second Advisor

Jon Pearce

Third Advisor

Philip Heller


Earmarked Unspent Transaction Outputs, Bitcoin user designation, Bitcoin Escrow, decentralized 2FA


The security of accounts on the blockchain relies on securing private keys, but they are often lost or compromised due to loopholes in key management strategies or due to human error. With an increasing number of thefts in the last few years due to compromised wallets, the security of digital currency has become a significant concern, and no matter how sophisticated and secure mechanisms are put in place to avoid the security risks, it is impossible to achieve a 100% human compliance.

This project introduces a novel concept of Earmarked Unspent Transaction Outputs (EUTXOs). EUTXOs enable every user on the blockchain to lock their funds to be spendable only to a designated set of users, even if the private key gets

compromised. We validate the utility of EUTXOs by using it to implement an Escrow service in

the blockchain to overcome the limitations introduced by traditional Escrow services. We also implement decentralized two-factor authentication (2FA) on the blockchain using EUTXOs and discuss the tradeoffs of this design.