Terra Quantum's analysis compares signature sizes for blockchain use and reviews mitigation plans across Solana, Algorand and Ethereum. Its preferred compact option is still under draft standardization
A cryptographically relevant quantum computer could use Shor's algorithm to derive private keys from widely used blockchain signatures. Terra Quantum AG's new analysis says recent resource estimates may put that capability closer in physical-qubit terms than earlier projections suggested; it does not report a quantum computer performing the attack. The risk to current signature schemes is long-term: a sufficiently capable, fault-tolerant quantum computer could solve the discrete-logarithm problem underlying elliptic-curve signatures, but no machine at that scale has been demonstrated.
The signature bottleneck
The white paper and companion research study examine ECDSA (secp256k1) and Ed25519, both vulnerable to private-key derivation using Shor's algorithm if a quantum computer reaches cryptographically relevant scale. The concern is conditional: the attack requires a quantum computer capable of carrying it out. Recent estimates cited in the analysis suggest that breaking elliptic-curve discrete logarithms may require up to 20 times fewer physical qubits than previously projected. That is a change in resource estimates, not a demonstration of cryptographic failure.
On August 13, 2024, the U.S. National Institute of Standards and Technology (NIST) finalized its first three post-quantum cryptography standards: FIPS 203 for ML-KEM, used for key establishment; FIPS 204 for ML-DSA, a digital-signature algorithm derived from CRYSTALS-Dilithium; and FIPS 205 for SLH-DSA, another signature scheme. The finalized standards establish deployable post-quantum options, while Falcon/FN-DSA follows a separate standardization track. NIST's FIPS 204 standard specifies ML-DSA for digital signatures.
Bytes matter
For blockchain transactions, the paper identifies signature payload size as the main technical obstacle to integrating post-quantum cryptography. Larger signatures add data to transactions and can increase network traffic and storage requirements, particularly for ledgers designed to process transactions at high throughput.
The comparison is stark: finalized NIST standard ML-DSA-44 (Dilithium) produces a 2,420-byte signature and a 1,312-byte public key. The signature is reported as 38 times the size of an Ed25519 signature. Terra Quantum identifies FN-DSA (Falcon-512, under draft standard FIPS 206) as the more viable candidate for transaction layers, with signatures of no more than 666 bytes and a public key of about 897 bytes. Falcon-512's signature is approximately 3.6 times smaller than the ML-DSA-44 signature, though it remains larger than a classical elliptic-curve signature. A technical comparison in Electronics likewise reports the compact Falcon component sizes.
These figures describe algorithm parameters, not measured changes in a live blockchain's speed or cost. The choice of a signature scheme also involves public-key size, verification speed, implementation complexity and compatibility with existing protocols. ML-DSA-44 is a finalized standard; FN-DSA/Falcon remains on a separate draft-standardization track. Its smaller signature does not by itself resolve the engineering work required to migrate accounts and transaction formats.
Different migration routes
The paper assesses several approaches already discussed within blockchain ecosystems. Solana's application-level Winternitz One-Time Signature (WOTS) vaults are one route reviewed. The analysis also considers Algorand's state proofs and its roadmap for native Falcon accounts.
For Ethereum, it examines EIP-8052, a proposal for EVM-native Falcon-512 verification precompiles. That is a proposal, not a completed Ethereum upgrade. Each route places cryptographic changes at a different layer, and the release describes migration approaches rather than completed network-wide transitions.
The broader challenge has a counterpart in web security: Cloudflare's certificate work also concerns adapting established infrastructure to post-quantum methods. Blockchain account signatures bring a distinct constraint, because the size of each signature can affect transaction data as well as verification.
What the study establishes
Terra Quantum published the white paper on September 15, 2026, and points readers to a technical manuscript on arXiv. The paper sets out proposed migration paths and compares signature sizes; it does not present measured deployment results, transaction-throughput comparisons or implementation audits. The proposals therefore remain frameworks for evaluation rather than completed network upgrades.
Post-quantum cryptography is designed to run on conventional computers using algorithms intended to resist attacks from future quantum computers. It is separate from quantum cryptography, which uses quantum systems as part of a communication protocol. In NIST's standards, ML-KEM is for key establishment, while ML-DSA and SLH-DSA are digital-signature algorithms. Replacing a signature algorithm involves more than selecting a cryptographic primitive: networks must implement and verify it securely while managing changes to transaction formats and existing accounts.
