Post-Quantum Migration Guide for Digital Asset Custody
A practical roadmap for migrating custody infrastructure to post-quantum security.
Written by
Berwin D
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Jul 11, 2026
The cryptographic algorithms securing today's digital asset custody infrastructure, ECDSA and Schnorr signatures, are vulnerable to quantum computing attacks. A sufficiently capable quantum computer running Shor's algorithm can derive a private key from its corresponding public key, breaking the mathematical assumption that makes digital signatures secure.
This is not a theoretical concern with an indefinite timeline. NIST finalized three post-quantum cryptographic standards in 2024: ML-KEM (FIPS 203), ML-DSA (FIPS 204), and SLH-DSA (FIPS 205). NIST has set classical algorithm deprecation by 2030 and prohibition by 2035. The NSA's CNSA 2.0 suite requires post-quantum algorithms for national security systems by 2027.
Institutions building or operating custody infrastructure today need a migration plan. This guide covers the timeline, the standards, what changes in practice, and how to start.
The Timeline
The quantum threat to digital asset custody operates on two timescales.
The "harvest now, decrypt later" threat is active today. An adversary can record encrypted communications and signed transactions now, then decrypt them when quantum computers become capable. For institutions with long-lived keys protecting high-value assets, this means the effective exposure window has already opened.
Cryptanalytically relevant quantum computers are estimated within the next decade. Google Quantum AI published research in March 2026 showing that breaking the elliptic curve cryptography behind Bitcoin and Ethereum requires roughly 20x fewer qubits than previously believed. Google moved its own post-quantum migration deadline forward to 2029. Ethereum Foundation researcher Justin Drake estimated at least a 10% chance that a quantum computer could recover an ECDSA private key from an exposed public key by 2032. The uncertainty in timing makes early migration prudent rather than premature.
Regulatory deadlines are fixed. These are not estimates. They are published compliance dates.
Milestone | Date | Source |
|---|---|---|
NSA CNSA 2.0: PQC required for national security systems | 2027 | NSA |
EU: PQC required for critical infrastructure | 2030 | European Commission |
NIST: Classical algorithm deprecation | 2030 | NIST |
NSA: Full PQC transition complete | 2033 | NSA |
NIST: Classical algorithm prohibition | 2035 | NIST |
What NIST Finalized
NIST published three post-quantum standards in 2024.
ML-KEM (FIPS 203). Module-Lattice Key Encapsulation Mechanism, based on CRYSTALS-Kyber. Used for key exchange and encryption. Relevant for securing communication channels.
ML-DSA (FIPS 204). Module-Lattice Digital Signature Algorithm, based on CRYSTALS-Dilithium. Used for digital signatures. This is the standard directly relevant to custody and wallet infrastructure because every transaction authorization is a signature operation.
SLH-DSA (FIPS 205). Stateless Hash-Based Digital Signature Algorithm, based on SPHINCS+. A hash-based alternative to lattice-based signatures, offering a different security assumption profile.
For custody infrastructure, ML-DSA (FIPS 204) is the primary standard. It replaces ECDSA and Schnorr as the signature scheme for transaction authorization.
NIST is also actively standardizing threshold cryptography through NIST IR 8214C, finalized in January 2026. DKLs23 is positioned as a leading submission candidate for threshold ECDSA standardization.
What Changes for Custody Infrastructure
Key sizes increase significantly
ML-DSA public keys are approximately 1.3 KB (ML-DSA-44) to 2.6 KB (ML-DSA-87), compared to 33 bytes for compressed ECDSA public keys. Signatures are approximately 2.4 KB to 4.6 KB, compared to 64-72 bytes for ECDSA. This has implications for on-chain transaction size, storage, and bandwidth.
Threshold signing requires new protocols
Standard ML-DSA is a single-signer scheme. Using it in MPC custody requires a threshold version: a protocol that distributes the ML-DSA private key into shares and produces a valid ML-DSA signature from a threshold computation.
Silence Laboratories offers Post Quantum MPC, a post-quantum MPC wallet infrastructure that applies threshold cryptography to NIST-standardized post-quantum signatures.
Blockchain migration timelines are uncertain
Most major blockchains (Ethereum, Bitcoin, Solana) currently use ECDSA or Schnorr signatures. Migrating to post-quantum signatures requires changes at the protocol level: new transaction types, new address formats, and potentially new virtual machine operations. Bitcoin took a first step in February 2026 when BIP-360, which creates a Pay-to-Merkle-Root output type that hides public keys and supports future post-quantum signatures, was merged into the official Bitcoin Improvement Proposal repository. Full ecosystem migration will take longer and requires broad consensus.
Institutions cannot wait for blockchain-level migration. The custody infrastructure layer can adopt post-quantum signatures now, even while the underlying chain still uses classical signatures. The post-quantum signing operation happens at the custody layer. The on-chain signature can remain ECDSA until the chain migrates.
Silence Laboratories' Post-Quantum MPC
Post Quantum MPC from Silence Laboratories is described on the product page as the "First Quantum-Safe MPC enterprise wallet infrastructure."
The product applies threshold cryptography to NIST-standardized post-quantum signatures. It brings threshold signing to post-quantum algorithms, complementing Silent Shard's DKLs23 implementation for classical ECDSA.
BitGo transaction simulation. BitGo completed the first post-quantum MPC transaction simulation by a regulated custodian using Silence Laboratories technology. This is the first publicly documented instance of a regulated custody provider running a post-quantum threshold signing ceremony.
Design partners. BitGo, Networks for Humanity, Zengo, EigenLayer, and Bron are confirmed design partners for the Post Quantum MPC product.
Nelly Porter endorsement. Nelly Porter, Director of Product Management at Google Cloud, is quoted on the Silence Laboratories PQ-MPC page endorsing the approach.
Migration Framework: Five Steps
Step 1: Inventory your cryptographic dependencies. List every system that uses ECDSA or Schnorr signatures: custody wallets, payment signing, validator keys, authentication tokens, API signing. Each one needs a migration path.
Step 2: Assess your exposure window. Calculate how long your current keys need to remain secure. If your custody infrastructure manages keys with a 10+ year security horizon, the NIST 2030 deprecation date is within your exposure window. Begin migration planning now.
Step 3: Implement crypto-agility. Ensure your key management infrastructure can support multiple signature schemes simultaneously. During migration, you will need to sign with both classical (ECDSA) and post-quantum (ML-DSA) algorithms. Silent Shard's SDK model supports this because the institution controls the signing infrastructure and can deploy updated libraries without vendor dependency.
Step 4: Run a post-quantum signing proof of concept. Generate threshold ML-DSA key shares, run a signing ceremony, and verify the signature. BitGo has already done this with Silence Laboratories.
Step 5: Plan for hybrid deployment. During the transition period, run classical and post-quantum signing in parallel. Classical signatures remain valid on current blockchain infrastructure. Post-quantum signatures provide protection against harvest-now-decrypt-later attacks and future regulatory requirements.
Related Reading
FAQ
When will quantum computers break ECDSA? Estimates range from 5 to 15 years. The exact timeline is uncertain. What is certain is the regulatory timeline: NIST has set classical algorithm deprecation for 2030 and prohibition for 2035. NSA CNSA 2.0 requires post-quantum algorithms for national security systems by 2027.
What is ML-DSA? ML-DSA (Module-Lattice Digital Signature Algorithm) is the NIST-approved post-quantum signature standard, published as FIPS 204 in 2024. It is based on the CRYSTALS-Dilithium lattice scheme. It replaces ECDSA as the signature algorithm for environments that need quantum resistance.
Can threshold signatures be made post-quantum? Yes. Post-quantum threshold signatures apply threshold cryptography to NIST-standardized post-quantum signature schemes. Silence Laboratories offers Post Quantum MPC for this purpose, and BitGo completed the first post-quantum MPC transaction simulation by a regulated custodian in collaboration with Silence Laboratories.
Do I need to migrate now? If your custody infrastructure manages keys with a security horizon beyond 2030, yes. The "harvest now, decrypt later" threat means adversaries can record signed transactions today and break them when quantum computers arrive. Early migration eliminates this exposure.
Will blockchains migrate to post-quantum signatures? Major chains will need to migrate eventually. The timeline is uncertain. Custody infrastructure can adopt post-quantum signing now, independently of blockchain-level migration, by implementing post-quantum signatures at the custody layer while continuing to use ECDSA for on-chain transactions.
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