Practical, Anonymous, and Publicly Linkable Universally-Composable Reputation Systems

pRate: Anonymous Star Rating with Rating Secrecy

“…-The number of 1-star, 2-star and 3-star ratings is less than 16, i.e., n 1 , n 2 , n 3 ∈ [0, 2 4 ). The average score is higher than 4.6, i.e., (n 1 + 2n 2 + 3n 3 + 4n 4 + 5n 5 )/(n 1 + n 2 + n 3 + n 4 + n 5 ) > 4.6 which can be proved by showing n 4 , n 5 ∈ [0, 2 10 ) and (−18n 10 ). -The score was updated no earlier than 1 Oct 2018, i.e., t > 6848 where 6848 is the number of days elapsed from 1 Jan 2000 to 1 Oct 2018.…”

“…These systems focus on protecting anonymity for the rater but not for the ratee and they do not consider how to manage and protect reputation scores. Similar considerations apply to the scheme in [10] which mainly focuses on the universal composability of reputation systems. An anonymous reputation system which gives users rewards for submitting useful comments is presented in [15].…”

“…Each user uses a pseudonym for reporting readings within a certain period and transfers the gained score to the next pseudonym when the next time period starts while preventing attackers from linking these pseudonyms. Reputation systems proposed in [9][10][11] allow each user to anonymously rate a product at most once. If a user rates the same product multiple times, his anonymity will be broken because these ratings are linkable.…”

“…Various privacy-preserving reputation schemes [5,6,[9][10][11]15,[20][21][22] (see also Section 7 for more discussion) have been proposed to protect anonymity of raters and ratees to some extent, but none of these aims to hide reputation scores against the reputation manager. As far as we know, only [27,30,36] discuss the protection of reputation scores.…”

“…, where v is fixed and each n i represents the number of received i-stars. For example, v = 5 implies that a single rating can contain up to five stars and a score (10,20,30,40,50) in this case would mean that the user has received a total of ten 1-star, twenty 2-star, thirty 3-star, forty 4-star and fifty 5-star individual ratings. A user's reputation score is aggregated in a reputation credential which is blindly signed by the RM.…”