A scalable post quantum secure blockchain framework with adaptive time consensus in cloud environments.

Blockchain deployments continue to face challenges related to scalability, energy consumption, and susceptibility of classical cryptographic primitives to emerging quantum attacks. Conventional systems employing RSA or DSA signatures and consensus mechanisms such as Proof of Work (PoW) or Proof of Stake (PoS) incur substantial computational overhead and are not well suited for cloud-scale execution. This study presents PQ-PoETChain, a post-quantum-secure blockchain model integrating NTRU-based signatures, an adaptive Proof of Elapsed Time (PoET) protocol executed within Trusted Execution Environments (TEEs), and a Lightweight Hash Validation (LHV) mechanism. The framework was implemented in Python and evaluated in a controlled simulation environment using 50-1000 nodes, with repeated trials to measure variability across throughput, latency, and energy metrics. NTRU demonstrated sub-2 ms signature operations, while the adaptive PoET configuration reduced consensus delay under load-dependent conditions. Across multiple experimental runs, the system achieved an average throughput of ~ 195 TPS with a latency of 189 ± 4 ms at 500 nodes. Energy consumption reduced by up to 91.8% (± 1.6%) when compared with PoW under identical conditions. LHV further lowered verification cost by replacing Merkle-tree traversal with constant-time hash-pointer validation. Results indicate that PQ-PoETChain offers a balanced combination of quantum-resilient security and improved performance characteristics suitable for cloud-native and large-scale deployments.