Advanced adversaries, such as nation-states, are silently amassing encrypted records specifically to unlock them once quantum technology matures. Because enterprises are mandated by law to retain identity logs, archives, and confidential files for multiple years, these records stay exposed to upcoming decryption efforts. A very active tactic titled harvest now, decrypt later is already underway.
Distributed ledgers are especially vulnerable. Unlike fleeting messaging tools, blockchains permanently safeguard funds, identities, agreements, and governance. Absent early defensive measures, we run the risk of leaving the very core of decentralized finance and governance exposed to tomorrow’s quantum-driven breaches.
If decentralized networks are meant to act as the pillar for money, governance, and identity, they must be engineered for the quantum era — relying not on exotic hardware, but on superior mathematics.
A shift in cryptography
Legacy cryptography, such as RSA, depends on the complexity of factoring extremely large prime numbers. For decades, that computational difficulty was sufficient. However, in 1994, Peter Shor of MIT demonstrated that a quantum computer could resolve these challenges exponentially faster, turning difficult puzzles into easily solvable ones.
Post-quantum cryptography (PQC) arose as a countermeasure. Instead of depending on the difficulty of a single puzzle, PQC conceals information in ways that compel attackers to execute an impractical quantity of guesses. The traditional McEliece cryptosystem, introduced in 1978, remains viewed as one of the most robust PQC methodologies. Yet it incurs a penalty: encrypting and decrypting everything through McEliece demands so much computing power that it resembles a cure that almost destroys the patient alongside the illness.
Within the blockchain sector, developers have taken several critical steps to pragmatically tackle post-quantum cryptography. The Ethereum Foundation has supported an investigative team known as ZKnox, focusing on open-source post-quantum solutions capable of reducing gas expenses by as much as 12× while safeguarding Ethereum’s long-term viability against quantum dangers. Algorand is protecting its complete chain ledger utilizing FALCON signatures for post-quantum resilience.
A MIT coding breakthrough
Here lies the crucial realization: you do not need to encrypt every single piece of information to achieve quantum safety. Decrypting the entirety is computationally demanding and extremely costly.
Random Linear Network Coding (RLNC), an encoding technique formulated over two decades within my MIT laboratory, the “Network Coding and Reliable Communications Group,” presents a proven alternative. RLNC takes information and divides it into encoded equations, which can subsequently be mixed and reassembled as they traverse the network.
Conventional PQC is expensive because it mandates the encryption and decryption of all data. Through PQC encryption via RLNC, you only need to encrypt a portion — for instance, one out of ten coded equations — and the entire dataset inherits its quantum-resilient defense.
Utilizing RLNC, encrypting 10% of the information successfully secures 100% of the dataset, while eliminating 90% of the computational load. More importantly, the entire approach rests on pure mathematics. Because RLNC involves encoding and decoding information into packets, it can be embedded at any tier of the Web3 stack, facilitating quantum-secure, scalable performance across decentralized systems.
At the application layer, the math is applied at the software tier and regulated locally, representing the most rapid path toward implementation. At the infrastructure level, we have synthesized RLNC into hardware silicon at MIT, demonstrating that this technique scales down to physical chips and into the heart of blockchain nodes, securing long-term systemic robustness with minimal overhead.
Ultimately, RLNC can additionally be utilized as a “quantum-safe memory layer” for blockchains. It provides a method to guarantee that data distribution, archiving, and writing to the ledger inherit quantum security without requiring every transaction to undergo painfully intensive end-to-end encryption.
The call to action
Institutions will refuse to migrate their financial architectures, identity networks, or governance frameworks onto public blockchains unless those networks are demonstrably future-proof. Furthermore, we do not need to wait for quantum machines to materialize before erecting defenses against them. By that point, it will be far too late; the information will have already been harvested.
As I frequently remind audiences, there is nothing inherently quantum regarding post-quantum security. It is purely about coding. Pen-and-paper mathematics. Despite common misconceptions, owning a quantum machine is not a prerequisite for achieving quantum safety.
If blockchains are destined to function as the backbone for finance, governance, and the Internet of Things (IoT), they must be engineered not only for scalability but to withstand quantum threats. With RLNC, we finally possess a mechanism to make quantum security both practical and performant.
Originally published at https://www.coindesk.com/opinion/2026/09/13/quantum-proof-blockchain-why-math-not-machines-holds-the-key.
