Ledger CTO: Post-Quantum Cryptography Migration Enters Critical Phase, Blockchain Prefers Hash Signature Solutions

On April 23, Ledger’s Chief Technology Officer Charles Guillemet stated that "post-quantum cryptography is entering a critical stage. Although it remains uncertain when quantum computers with practical cryptographic implications will emerge, the industry widely believes that the migration to post-quantum systems is inevitable. A clear timeline has been established in traditional sectors, led by the National Institute of Standards and Technology (NIST), which plans to eliminate existing vulnerable algorithms by 2030 and fully ban them by 2035. Major enterprises and government agencies are currently accelerating preparations, aiming to complete migration capability development by 2029. In terms of technical pathways, encryption and key exchange will shift to ML-KEM (formerly CRYSTALS-Kyber) to address the risk of quantum attacks characterized by ‘collect first, decrypt later.’ However, in the blockchain ecosystem, the core issue is more focused on digital signatures. The current mainstream post-quantum signature solutions are divided into two categories: lattice-based ML-DSA (formerly CRYSTALS-Dilithium) and hash-based SLH-DSA (formerly SPHINCS+). Traditional industries tend to prefer ML-DSA and its hybrid solutions with ECC, while the blockchain sector leans towards the more conservatively secure and structurally simpler hash signature solutions. Each category has its trade-offs: ML-DSA offers better performance but its security assumptions have not undergone long-term validation; SLH-DSA, while less efficient, relies on a mature hash function system, providing more certainty in security. For blockchains that emphasize long-term security and verification pathways, the latter is more appealing. However, regardless of the chosen solution, the compatibility of multi-party computation (MPC) and threshold signatures remains an unresolved challenge, which is particularly critical in industries based on custodial and collaborative signing.