TriviA: A Fast and Secure Authenticated Encryption Scheme

In this paper, we propose a new hardware friendly authenticated encryption (AE) scheme TriviA based on (i) a stream cipher for generating keys for the ciphertext and the tag, and (ii) a pairwise independent hash to compute the tag. We have adopted one of the ISOstandardized stream ciphers for lightweight cryptography, namely Trivium, to obtain our underlying stream cipher. This new stream cipher has a state that is a little larger than the state of Trivium to accommodate a 128-bit secret key and IV. Our pairwise independent hash is also an adaptation of the EHC or “Encode-Hash-Combine” hash, that requires the optimum number of field multiplications and hence requires small hardware footprint. We have implemented the design in synthesizable RTL. Pre-layout synthesis, using 65 nm standard cell technology under typical operating conditions, reveals that TriviA is able to achieve a high throughput of 91.2 Gbps for an area of 24.4 KGE. We prove that our construction has at least 128-bit security for privacy and 124-bit security of authenticity under the assumption that the underlying stream cipher produces a pseudorandom bit stream.