What it is. Sei is a fast trading-focused blockchain whose current security relies entirely on the kind of math a powerful future quantum computer could break.
What we found. We searched Sei's blog, docs, social account and code and found no sign the team has ever publicly mentioned the quantum problem, even while it keeps shipping big speed upgrades.
Why it matters. If a chain that updates this often has not even named the risk, holders and builders have no plan to count on and old account signatures stay exposed once such a computer arrives.
Sei has not made any public PQ acknowledgement that LayerQu has located. Searches across blog.sei.io, docs.sei.io, the Sei X account, and the sei-protocol/sei-chain GitHub repo returned no result for 'post-quantum,' 'PQC,' 'ML-DSA,' 'Falcon,' 'SLH-DSA,' 'Dilithium,' or 'lattice signature.' Absence of signal in 2026, with NIST IR 8547 final and standardized PQ primitives available since 2024, is itself the finding.
Summary
Sei is a Cosmos-SDK-based proof-of-stake L1 with parallelized EVM execution layered on top of Tendermint/CometBFT consensus. Mainnet (Pacific-1) has run since 2023-08-15; Sei v2 added EVM compatibility in July 2024; the Giga upgrade with Autobahn multi-proposer consensus is in development with whitepaper published 2025-05-19, and the SIP-3 transition to an EVM-only chain is rolling out through 2026 (v6.4 mainnet 2026-04-13). Validator consensus signing uses CometBFT Ed25519. Cosmos and EVM accounts both use ECDSA secp256k1. Hashing uses SHA-256 and Keccak-256. Every primitive in active use is classically secure but Shor-vulnerable (Ed25519, ECDSA) or Grover-weakened (SHA-256, Keccak-256). Zero post-quantum primitives are deployed, specified, or announced. No public PQ posture from Sei Labs or Sei Foundation has been located. Giga's Autobahn redesign is throughput-focused (5 gigagas target via multi-proposer DAG-style consensus), not PQ. SIP-3 narrows surface to EVM but does not change cryptographic primitives. Gate 1a-Sig FAIL, Gate 1a-KEM FAIL. QRI 20, Band 1 Unaware.
What the gates say
- Gate 1a, Hybrid signature: FAIL , no hybrid signature composition AND or OR documented anywhere in Sei spec / code / blog
- Gate 1a, Hybrid KEM: FAIL , validator gossip / RPC TLS uses classical X25519 / ECDHE / RSA at infrastructure level; no hybrid PQ KEM documented
- Gate 1b, Commit-to-hash: COND , no OR-composition declared
- Gate 2, Evidence reconstruction: PASS , every sub-score has ≥3 public URLs; sub-score 1d voided because no PQC primitive exists to map
- Gate 3, Primitive naming: PASS , CometBFT Ed25519, ECDSA secp256k1, SHA-256, Keccak-256 named with mechanism
Burn-vs-rescue policy on file
Declared option f, Undeclared. Sei has published no policy on what happens to value at quantum-vulnerable addresses post-CRQC.
Seven dimensions
Each dimension scores 0–100 internally; the weighted roll-up produces the QRI.
1 Cryptographic Exposure weight 15% 28 / 100
Specific NIST curve / EdDSA parameter sets are not exhaustively documented in a single foundation spec page.
CometBFT Ed25519 (validator consensus signing per Cosmos-SDK convention) · ECDSA secp256k1 (Cosmos-side accounts) · ECDSA secp256k1 (EVM-side accounts post-v2) · SHA-256 (hashing) · Keccak-256 (EVM hashing) Ed25519→ Shor-break-via-DL-without-pairingsECDSA secp256k1→ Shor-break-via-DL-without-pairingsSHA-256→ Grover-weakenKeccak-256→ Grover-weaken
Every active primitive sits in classical elliptic-curve discrete-log or SHA-2/Keccak hash. No lattice, hash-based-signature, code-based, or isogeny family deployed.
VOID, no PQC primitives in deployment, so no NIST IR 8547 category mapping applies.
Standard Cosmos-SDK Ed25519 implementation; no published formal verification (no Formosa-Crypto / EasyCrypt machine-checked artifacts); no constant-time audit publication located; library provenance is the standard Cosmos-SDK + sei-chain fork. Cryptanalytic tier 1.
2 Quantum Recovery Exposure weight 10% 18 / 100
Every transaction reveals the spending public key (Cosmos accounts and EVM accounts both expose ECDSA secp256k1 pubkeys at first send); validator Ed25519 pubkeys are public from genesis. All active stake is forgeable post-Shor.
Same exposure model as Ethereum-style EVM and standard Cosmos accounts, once a key has signed, the pubkey is on-chain and Shor-recoverable. No address scheme that hides pubkey behind a hash-only commitment is in production.
Historical block signatures (Ed25519) and historical tx signatures (ECDSA) are forgeable under future CRQC. Sei has no checkpoint-anchoring or re-signing protocol declared.
Validator gossip transport (CometBFT p2p) and RPC endpoints rely on classical TLS (X25519 / ECDHE / RSA stacks at infrastructure level); no hybrid PQ KEM is documented.
3 Metadata, Anonymity & Confidentiality weight 13% 28 / 100
Pseudonymous transparent ledger (Cosmos + EVM); full tx graph public via seistream.app and standard EVM explorers.
Top RPCs include Sei Foundation endpoints, QuickNode, Ankr; mempool gossip via CometBFT p2p (observable to any validator); validator metadata-retention policy is undeclared in published docs.
IBC connections (winding down per SIP-3 / v6.4 inbound-disable), LayerZero, Wormhole. Cross-chain observers can correlate flows.
No on-chain encryption primitives that would expose retroactive privacy beyond what tx-graph already reveals. Pseudonymity does not survive post-Shor address-clustering on revealed pubkeys, but no encrypted note system to retroactively decrypt.
No protocol-level mixing, shuffle, or commit-reveal mechanism on Sei.
4 Migration Architecture weight 10% 35 / 100
Cosmos-SDK provides module-based architecture and coordinated hard-forks (Sei has shipped multiple, v2 EVM in 2024, v6.4 in April 2026). The signature-scheme switch path is not documented as a single algorithm-agility hook; switch would require coordinated upgrade.
Standard Cosmos key rotation via tx-message; EVM side inherits ERC-4337-compatible AA tooling but no Sei-native AA spec located; no client-layer PQ path documented.
Coordinated v2 EVM upgrade (July 2024); coordinated SIP-3 vote (2025) and v6.4 mainnet rollout (2026-04-13); Giga whitepaper (2025-05-19) and ongoing devnet validation. Track record of coordinated upgrades is solid for a 32-month-old chain.
Architecturally feasible via Cosmos-SDK module addition (parallel-validator-key registry), but not announced. Giga's Autobahn redesign focuses on throughput, not PQ.
N/A, no stateful-hash scheme deployed. Default 15/15 for stateless schemes.
N/A, CometBFT consensus uses Ed25519 (non-aggregating) per Cosmos-SDK default. Sei has not announced BLS-aggregation in consensus. Giga's Autobahn whitepaper does not introduce BLS aggregation; it changes proposer/data-dissemination structure, not the per-validator signing primitive.
5 Deployment Execution weight 22% 15 / 100
0% PQC signing traffic on mainnet.
No PQ primitive merged into sei-chain main branch as of evidence cutoff.
Zero validators using PQ keys.
VOIDED to 0 per v3.1 (5a = 0). No published PQ milestones with enforcement-mechanism evidence.
Ratio 0/0 (none-announced, none-shipped). No PQ marketing claims, no shipped PQ. announcement-to-shipped delta tag: none.
Undisclosed (no PQ scheme selected; therefore footprint multiplier cannot be computed). Per scoring rule, undisclosed = 0.
6 Supply Chain Vendor Readiness weight 22% 5 / 100
Top-3: Compass Wallet, Keplr, Leap Wallet (Cosmos-side); MetaMask, Rabby (EVM-side post-v2). None has a published PQ roadmap as of evidence cutoff.
Top-3: IBC (winding down per SIP-3), LayerZero, Wormhole. None publishes a PQC roadmap.
Top-3: BitGo, Coinbase Custody, Fireblocks (institutional Sei support). None has mainnet-deployed PQ MPC.
Top-3 RPC: Sei Foundation endpoints, QuickNode, Ankr; HSMs: standard YubiHSM / Ledger HSM patterns documented for Sei validators; no PQ HSM published.
7 Governance & Coordination weight 8% 30 / 100
40-validator active set; Nakamoto coefficient 7 per third-party tracking 2026-05-01.
v2 (July 2024), v6.4 (2026-04-13), Giga devnet validation 2025. Coordinated upgrades have shipped on time; no contested forks.
Sei Foundation + Sei Labs (Jay Jog, Jeff Feng co-founders publicly named). No PQ working group / PQ-named lead.
No precedent of coordinating a cryptographic change under active attacker. SIP-3 was contested in community discussion (CosmWasm developers / native-Cosmos users opposed) but not adversarial in the cryptographic sense.
No canary, no rate-limit-on-spend, no cryptographic tripwire embedded in consensus.
X + Y vs Z, when does the math turn against you?
v3.1 demotes the X+Y vs Z timing test to a secondary signal, the headline output is Migration Stage. The timing test still answers the question: can this chain finish migrating before the threat lands?
Verdict
X+Y range 15–25 years (2041–2051), Crisis Zone (vs Z10 2030); Outside risk window (vs Z25 2035)
Z-compliance
Outside compliance window (X+Y > 2035, Sei Labs is US-incorporated, NIST IR 8547 deprecates classical PK 2030 / disallows 2035)
Source-disagreement disclosure
v3.1 requires every chain card to publish material divergences among authoritative sources, plus the delta-QRI under alternative weighting.
Sei docs do not name Ed25519 directly on a single page; the inference comes from inheriting the standard Cosmos-SDK / CometBFT default plus Sei validator-operations doc references to priv_validator_key.json (the Tendermint validator-key file format, which uses Ed25519 by default in Cosmos-SDK). High confidence but worth stating.
Verified to 'July 2024' but no exact day located in foundation sources. Sei Labs announced stability-of-v2 in May 2024 and the actual mainnet upgrade rolled through three phases in July 2024.
Delta-QRI under alternative weighting
Under a higher-weight-on-Dim-7 governance view (which would credit Sei's coordinated v2/v6.4/Giga upgrade cadence more heavily), QRI shifts +3 to ~23 (still Band 2). Under a higher-weight-on-Dim-5 deployment view, QRI shifts -2 to ~18 (Band 1 Unaware). Either way, Stage stays 0.
Announcement-to-shipped ratio
Announced: 0. Shipped: 0. Ratio: 0.
Tag: none, no washing risk because no PQ marketing exists
Peers in the L1 profile
9 chains closest to Sei by Stage then QRI.