Lattice based post quantum blockchain identity verification with zero knowledge proofs for decentralized finance

Digital identity verification in decentralized finance (DeFi) still depends on classical public key primitives such as RSA 2048 and ECDSA 256, which a cryptographically relevant quantum computer running Shor’s algorithm can break, while centralized identity providers add single points of failure and cannot sustain high volume DeFi workloads. Existing post quantum proposals either harden isolated primitives without an end-to-end identity architecture or overlook the privacy, revocation, and interoperability requirements of DeFi protocols. This paper addresses that gap through a quantum resilient blockchain framework whose technical novelty lies in a unified verification protocol that integrates a lattice based signature scheme (CRYSTALS Dilithium at NIST security level 3), a transparent zero knowledge proof layer for selective credential disclosure, decentralized identifiers with verifiable credentials, a Merkle accumulator for decentralized revocation, and a hybrid consensus engine under a single formally specified acceptance predicate. In simulation based experiments on a permissioned testbed scaled from 500 to 2000 validator nodes, the framework attains a per verification cryptographic latency of 22 ms and a committee level throughput of 1100 identity verifications per second, with aggregate network throughput scaling to 4200 TPS at 2000 nodes, corresponding to a latency reduction of approximately 91% relative to the RSA 2048 baseline, a throughput gain of approximately 37% relative to the ECDSA 256 baseline, and a latency reduction of approximately 77% relative to a plain lattice based baseline. Under simulated quantum attack scenarios, the framework sustains verification success above 94% and a composite security score of 96 out of 100, while revocation checks complete in under 40 ms and per verification energy remains below 9 J. These results indicate a scalable and quantum resilient identity infrastructure for DeFi.