Sonic redesigns PoS chain to ease post-quantum signature swap

Sonic has redesigned its proof-of-stake blockchain to avoid Boneh–Lynn–Shacham (BLS) signature aggregation and to make it simpler to adopt post-quantum signature schemes. The protocol uses a directed acyclic graph consensus, called Sonic Consensus System (SonicCS), in which each event carries its own signature and links to prior events by hash.

Current proof-of-stake networks often compress validator approvals with BLS or threshold signatures to reduce message size. Sonic removed that aggregated-proof requirement and records individually signed events connected by hash references. The signed events and hash links preserve ordering and the chain of custody while keeping signatures independent.

Sonic’s design responds to the long-term risk posed by quantum computing to common elliptic-curve algorithms such as ECDSA and Ed25519. A sufficiently powerful quantum computer running Shor’s algorithm could derive private keys from public keys used by those schemes. Aggregation methods like BLS depend on cryptographic assumptions that would be affected if those primitives become insecure.

Post-quantum alternatives include hash-based and lattice-based signature schemes. Those options are generally larger in byte size and do not support the same compact aggregation techniques used today. Replacing aggregated signatures on a running network can increase message sizes and verification workloads. Sonic says separating signatures from the aggregation logic lets a network swap the signing algorithm on each event without changing the consensus rules that order and finalize messages. The company says the architecture is intended to reduce the operational and bandwidth costs associated with larger post-quantum signatures.

Bernhard Scholz, Sonic’s chief research officer, said, “Whether sufficiently powerful quantum computers arrive tomorrow or in 50 years, the industry must be prepared.” He added that the technical challenge is not only picking a quantum-resistant primitive but integrating it into a live consensus system while managing costs.

Sonic plans to monitor developments in post-quantum cryptography and standards work tied to major ecosystems. For now, practical quantum attacks remain theoretical. Network developers continue to balance performance, bandwidth and upgradeability when evaluating post-quantum options.