Bounded vector signatures and their applications

Abstract

Although malleability is undesirable in traditional digital signatures, schemes with limited malleability properties enable interesting functionalities that may be impossible to obtain otherwise (e.g., homomorphic signatures). In this paper, we introduce a new malleable signature scheme called bounded vector signatures. The proposed scheme allows a user to sign a multi-dimensional vector of values, along with a description of the context within which the vector should be interpreted. The scheme includes a unique malleability property, which we refer to as the stretch property, that allows the components of the signed vector to be increased up to a pre-defined limit without access to the signing key. Decreasing these values, however, remains computationally infeasible. We prove the security of our construction under the strong RSA and decisional Diffie-Hellman assumptions in the random oracle model. Finally, we underscore the utility of bounded vector signatures by discussing their use in distributed systems security applications.