In cryptography, the common reference string (CRS) model captures the assumption that a trusted setup in which all involved parties get access to the same string crs taken from some distribution D exists. Schemes proven secure

Provable security

In cryptography, a system has provable security if its security requirements can be stated formally in an adversarial model, as opposed to heuristically, with clear assumptions that the adversary has access to the system as well as enough computational resources...

 in the CRS model are secure given that the setup was performed correctly. The common reference string model is a generalization of the common random string model, in which D is the uniform distribution of bit strings. As stated in , the CRS model is equivalent to the reference string model and the public parameters model .

The CRS model has applications in the study of non-interactive zero-knowledge proof

Non-interactive zero-knowledge proof

Non-interactive zero-knowledge proofs are a variant of zero-knowledge proofs. Blum, Feldman, and Micali showed that a common reference string shared between the prover and the verifier is enough to achieve computational zero-knowledge without requiring interaction. Goldreich and Oren gave...

s and universal composability

Universal composability

The framework of Universal Composability is a general-purpose model for the analysis of cryptographic protocols. It guarantees very strong security properties. Protocols remain secure even if arbitrarily composed with other instances of the same or other protocols. Security is defined in the...

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