
Briefing
The core research problem is the existential threat posed by large-scale quantum computers to the Elliptic Curve Cryptography (ECC) and RSA primitives that underpin all current blockchain security, creating a “Harvest Now, Decrypt Later” vulnerability. The foundational breakthrough is the strategic migration to Post-Quantum Cryptography (PQC) families, primarily Lattice-Based Cryptography , whose security is rooted in the mathematical hardness of structured lattice problems, a complexity class believed to be quantum-resistant. This migration requires a fundamental, coordinated upgrade of the entire cryptographic stack ∞ from key exchange to digital signatures ∞ and the single most important implication is the necessity of crypto-agility to ensure the long-term integrity and trust of all decentralized ledgers.

Context
The established theoretical foundation of blockchain security relies heavily on the perceived difficulty of classical number theory problems, specifically the discrete logarithm problem for ECC and the factoring problem for RSA. This foundation is critically compromised by Shor’s algorithm, which, when run on a sufficiently powerful quantum computer, can solve these problems in polynomial time. This theoretical limitation presents an urgent, non-negotiable challenge, as adversaries can currently collect encrypted data and signed transactions, anticipating a future ability to decrypt and forge them, thus compromising the long-term security and immutability of the ledger.

Analysis
The paper outlines the strategic shift from classical public-key schemes to PQC families, with Lattice-Based Cryptography (LBC) emerging as the high-performance anchor. LBC shifts the security assumption from number theory to the complexity of solving linear algebra problems over high-dimensional lattices, such as the Learning with Errors (LWE) or Shortest Vector Problem (SVP). This transition is not a simple patch but a full cryptographic transformation, replacing the vulnerable ECDSA signature scheme with lattice-based alternatives like ML-DSA (Dilithium) and the key exchange mechanism with ML-KEM (Kyber). The new mechanism provides quantum resistance while often maintaining or surpassing the computational efficiency of classical alternatives, a crucial factor for high-throughput blockchain environments.

Parameters
- NIST Standardized PQC Family ∞ Lattice-Based Cryptography. This family, exemplified by ML-KEM and ML-DSA, was selected by the National Institute of Standards and Technology (NIST) for standardization due to its balance of security and performance.
- Key-Encapsulation Mechanism Standard ∞ FIPS 203 (ML-KEM). This represents the official, high-performance, quantum-safe primitive for key exchange, a core component of secure communication and transaction encryption.
- Vulnerable Cryptographic Primitive ∞ Elliptic Curve Cryptography (ECC). The current backbone of blockchain digital signatures (ECDSA) and key management, which is rendered insecure by quantum computing.

Outlook
The immediate future of blockchain architecture is defined by the necessity of hybrid migration , where protocols run both classical and PQC primitives concurrently to hedge against both current and future threats while ensuring backward compatibility. This research opens new avenues for implementing quantum-safe solutions in resource-constrained environments like IoT devices and smart contracts, ensuring the long-term viability of decentralized finance and identity systems. Within three to five years, a fully quantum-resistant cryptographic layer will become a baseline requirement, driving research into side-channel attack mitigation and parameter agility for these new primitives.
