Identification and Mitigation of a Vulnerability in the ThreeBallot Voting Scheme

Recently, the ThreeBallot voting scheme has been proposed as a means of providing a voter with a non-transferable receipt for their vote without resorting to more traditional means of cryptography. The ThreeBallot scheme is attractive because voters are not required to either understand complex cryptography present in other voting schemes, or more usually, trust a software or hardware artifact to perform the cryptography on their behalf. This paper describes an attack on the ThreeBallot scheme not identified in the original paper and presents a potential strategy for mitigation. In addition, a more general comment is made on the need to identify suitable mechanisms for producing randomness in voting schemes.