Biblio

Motivated by the complexity of cryptographic proofs, we propose methods to automate the construction and verification of cryptographic proofs in the standard model. Proofs in the standard model (as opposed to the random oracle model) are the gold standard of cryptographic proofs, and most cryptographic protocols strive to achieve them. The burgeoning complexity of cryptographic proofs implies that such proofs are prone to errors, and are hard to write, much less verify. In this paper, we propose techniques to generate automated proofs for attribute-based encryption schemes in the standard model, building upon a prototype tool, AutoG&P due to Barthe et al. In doing so, we significantly expand the scope of AutoG&P to support a rich set of data types such as multi-dimensional arrays, and constructs commonly used in cryptographic protocols such as monotone-access structures, and linear secret-sharing schemes. We also provide support for a extended class of pairing-based assumptions. We demonstrate the usefulness of our extensions by giving automated proofs of the Lewko et al. attribute-based encryption scheme, and the Waters' ciphertext-policy attribute-based encryption scheme.