Cryptographic techniques referred to as Sender Optimal, Breach-resilient Auditing with Post-Quantum security (SOBAP) are described. Optimal efficiency and post-quantum security of symmetric key based techniques are achieved, while providing compromise-resiliency, conditional non-repudiation, and fault-tolerance verification in a distributed setting. SOBAP relies on any choice of a symmetric key based primitive with extended features (e.g., forward-security, append-only authentication), which can be optimally efficient. The verification is done via the execution of symmetric primitive F with a secure multi-party computation (SMPC) technique, wherein an honest majority guarantees a conditional non-repudiation and fault-tolerance. SOBAP offers an architecture that uses authenticated access control data structures to ensure policy enforcement. SOBAP also offers a post-quantum security via symmetric primitives and SMPC. Extensions of SOBAP offer oblivious access and enhancements with secure hardware support