Post-Quantum Cryptography (PQC)
Public-key cryptographic systems in widespread use today rely on math problems that are computationally infeasible for classical computers to solve. Quantum computers, in contrast, will be able to efficiently solve certain public-key problems, ultimately threatening the mechanisms used to manage keys and authenticate communications.
Post-quantum cryptography (PQC) is a field of cryptography developing algorithms and standards intended to resist attacks by classical and quantum computers. It covers digital signatures, key establishment, and encryption.
Is Quantum Computing a Threat to Crypto?
For crypto users, the concern largely centers on public-key exposure. On many blockchains, spending funds reveals the public key associated with the spending address. Once a public key is visible onchain, a sufficiently capable quantum attacker could potentially derive the corresponding private key, a risk particularly relevant to Elliptic Curve Digital Signature Algorithm (ECDSA) and other discrete-log-based signature schemes.
Some address formats delay this exposure until the point of spending, which affects the timing and scope of the risk. Adversaries aware of this dynamic may record revealed public keys today with the intent to target them once capable quantum hardware exists, a tactic known as Harvest Now, Decrypt Later (HNDL).
How The Crypto Industry Is Preparing For PQC
Cryptographically relevant quantum computers do not yet exist, but migration is recommended now because transitioning cryptographic infrastructure across wallets, nodes, and exchanges takes significant time and coordination.
NIST’s standardization process began in 2016 and has produced its first finalized standards. Two algorithm families under active consideration for blockchain and hardware wallet contexts are lattice-based schemes, such as ML-DSA and Falcon (FN-DSA), and hash-based schemes like SLH-DSA. Each involves trade-offs between signature size, memory requirements, and implementation complexity.
Preparing for the post-quantum era requires the ability to adopt new cryptographic standards without requiring a total hardware overhaul (crypto-agility). Ledger’s secure architecture is designed with this in mind, supporting algorithmic coexistence so that existing signing standards remain operational while new post-quantum algorithms can be added through firmware updates as they are adopted.
To learn more about how the Ledger Donjon is benchmarking PQC algorithms on Secure Element hardware and what it means for the future of hardware signing, read Quantum Computing’s Threat to Blockchain on the Ledger blog.
