Paper 2026/1634

MAYO Lite: a Low-RAM Implementation of the MAYO Signature Scheme

Abstract

MAYO is a signature scheme based on the Unbalanced Oil and Vinegar (UOV) construction and a third round candidate in the NIST standardization process for additional post-quantum signature schemes. We present a memory-optimized pure- C implementation of MAYO signature verification that reduces RAM consumption by 97–99% compared to the reference implementation provided by the PQM4 project [KPR+] at the cost of increasing runtime by 50–200% and while maintaining code size. This reduction finally enables verifying MAYO signatures on smart cards and small microcontrollers with only a few kilobytes of RAM. We achieve it through three coupled design choices: a) we expand the public key vector-by-vector on the fly rather than all at once at the start; b) we reorder the calculation of the matrix product SPS so that each vector of P is used exactly once, which avoids repeated expansions; and c) we add precomputed multiples of each P-vector directly onto the result instead of accumulating P-vectors before multiplication. We provide results using the PQM4 framework for all parameter sets listed in the specification and supported by PQM4 on our platform, including three main parameter sets MAYO{1,2,3}. This enables direct comparison with other post-quantum digital signature schemes. Further parameter sets not supported by PQM4, including the fourth main parameter set MAYO5, are measured on our own framework, which supports key and signature generation on the host. Our results for non-standard MAYO parameter sets offer insights into the performance and scalability of the proposed approach that may inform ongoing standardization efforts.