Asynchronous Information Checking Protocol (AICP) Sample Clauses

Asynchronous Information Checking Protocol (AICP). An Information Checking Protocol (ICP) is used for authen- ticating data in the presence of computationally unbounded corrupted parties. The notion of ICP was first introduced by Xxxxx et al. [29]. As described in [29, 9, 12], an ICP is exe- cuted among three parties: a Signer, an intermediary INT and a Verifier. Informally, an ICP consists of two phases (where each phase is implemented by different protocol(s)): ∈ – Signature generation phase: here Signer computes his IC (information checking) signature on a secret s F, denoted by ICSig(Signer, INT, Verifier, s) and hands it to INT. Signer also computes some verification infor- mation and hands it to Verifier. – Signature revelation phase: here INT reveals the signa- ture ICSig(Signer, INT, Verifier, s), claiming that he has received it from Signer. Verifier then verifies the sig- nature, using the verification information and either ac- cepts or rejects the signature (and hence s). IC signature may be considered as the information theoret- ically secure substitute of traditional digital signatures. It provides the properties like unforgeability and non-repudiation; in addition, it also provides information theoretic security. That is, if Signer and INT are honest, then at the end of the signature generation phase, s remains secure in the informa- tion theoretic sense. P P We extend the above notion of ICP in two directions: First, we consider multiple verifiers, where each party in acts as a Verifier. This will be later helpful in using the ICP as a tool in our AWC protocol. It is important here to note that Signer and INT can be any two parties from the set . They just play their “special” role as Signer and INT. Sec- ond, instead of a single secret, we consider ICP that can deal with multiple secrets concurrently and thus achieves better communication complexity, than executing multiple instances of ICP, dealing with a single secret. Our ICP is ex- ecuted in the asynchronous settings and thus we call it AICP. We now formally define AICP. P ∈ P ∈ P Definition 4 ((Multi-Verifier) Asynchronous Information Checking Protocol (AICP)) An AICP involves three enti- ties: a Signer , an intermediary INT and the set of n parties in acting as verifiers. The protocol is carried out in three phases (where each phase is implemented by a protocol): ∈