Post-Quantum Cryptography In The Ledger SDK Learn how Ledger has developed two post-quantum cryptography APIs into its SDK, the first step of enabling cryptography protocols quantum computers can't crack. Before You Dive In - The threat is real, but not here yet: A powerful enough quantum computer could break the math that protects most digital security today, including crypto wallets. It doesn’t exist yet, but the industry is preparing now so defenses are ready when it does. - Ledger has added two new algorithms in its SDK: These are called ML-KEM and ML-DSA. They replace older security methods with ones that even quantum computers can’t crack. - ML-KEM is for sharing secrets securely: Think of it like a lockbox: the recipient publishes an open lock (public key), the sender puts a secret inside and snaps it shut (encapsulation), and only the recipient can open it (decapsulation). Nobody else, including a quantum computer, can read what’s inside. - ML-DSA is for proving something is genuine: It works like a digital signature on a document: it proves a message came from who it says it came from, and hasn’t been tampered with. It’s the quantum-safe replacement for the signature method most blockchains use today. - The tradeoff is size, not security: These new methods are secure against future threats, but their keys and signatures are much larger than the old ones, sometimes 30–50x bigger. That’s a known cost of quantum resistance. - Ledger’s devices are small and have limited memory: So the implementation required clever engineering. Rather than loading everything into memory at once, the code rebuilds what it needs piece by piece, staying within tight hardware limits without cutting any security corners. - One important caveat the document flags openly: the current version doesn’t yet include protection against physical attacks (like