A reputation protocol computes the reputation of an entity by aggregating the feedback provided by other entities in the system. Reputation makes entities accountable for their behavior. Honest feedback is clearly a pre-requisite for accurate reputation scores. However, it has been observed that entities often hesitate in providing honest feedback, mainly due to the fear of retaliation. We present a privacy preserving reputation protocol which enables entities to provide feedback in a private and thus uninhibited manner. The protocol, termed k-shares, is oriented for decentralized environments. The protocol has linear message complexity under the semi-honest adversarial model, which is an improvement over comparable reputation protocols.