Electronic voting schemes usually use voting receipts to assure accuracy and verifiability of the tally. A traditional voting receipt consists of the blind signature of the voter's ballot made by the voting centre. However, this construction forces the voter to reveal in which way he/she voted in case an objection to the tally is done. The mechanism of vote-tags solves this problem, allowing open objection to the tally. Nonetheless, previous proposals for vote-tags imply high computation costs. In this paper we propose an efficient method to construct vote-tags, based on one-way hash functions.