For Web3 and blockchain

Threshold custody for on-chain assets

Single-key custody is the #1 operational risk in Web3. Confium replaces it with threshold key management — T-of-N quorum for every transaction, chain-agnostic, off-chain coordination.

The Web3 custody problem

Every blockchain wallet, DeFi protocol, and NFT marketplace has the same structural problem: whoever holds the private key holds the funds. Single-key custody means one compromise drains the treasury. Multi-sig smart contracts help but are chain-specific, add on-chain overhead, and expose signer identities on-chain.

Threshold cryptography gives you off-chain, chain-agnostic custody. The signing key is split across N custody parties; any T of them produce a valid signature. The chain sees a normal ECDSA or Ed25519 signature — no multi-sig contract, no on-chain overhead, no protocol change.

What Confium gives Web3

  • Chain-agnostic. Same threshold key infrastructure works for Bitcoin, Ethereum, Solana, Cardano, Aptos, Sui — any chain using ECDSA (secp256k1/P-256) or Ed25519.
  • Off-chain coordination. The coordinator runs off-chain; only the final signature touches the chain.
  • Attribute-based policy. "2-of-3 user devices for transactions under $1K; 5-of-7 board members for transactions over $100K".
  • HSM coexistence. Each custody share can be stored in a hardware HSM via PKCS#11. The share never leaves the HSM in plaintext.
  • Proactive refresh. Shares re-randomize periodically; a compromised share from last quarter is useless today.
  • Transparency log. Every transaction anchored for regulatory audit (SOC 2, NYDFS BitLicense, EU MiCA).

Architecture for a custody service

[ Wallet front-end (API / SDK) ]
           |
           | submit tx hash + policy
           v
[ Coordinator ] --------------------+
   |          |          |          |
   v          v          v          v
[Custody 1][Custody 2][Custody 3][Custody N]
   |          |          |          |
   +----------+---- T-of-N quorum --+
                      |
                      v
           [ Standard ECDSA signature ]
                      |
                      v
           [ Broadcast to chain ]
                      |
                      v
           [ Transparency log anchors event ]

Tiered authorization

Real custody operations have value-tiered policies. Confium's attribute DSL expresses them:

TierPolicyExample
Micro1-of-2 user devicesUnder $1K — instant withdrawal
Standard2-of-3 operations + 1-of-2 risk$1K–$100K — multi-stakeholder
Large3-of-5 ops + 2-of-3 risk + 1-of-1 compliance$100K–$1M — full governance
WhaleBoard resolution + 5-of-7 senior officersOver $1M — executive sign-off
Cold storage7-of-9 (board + custody + auditor)Reserve withdrawal — maximum quorum

The coordinator evaluates the policy per transaction and only advances when the quorum is satisfied.

Cross-chain examples

Ethereum (ECDSA secp256k1)

# Sign an Ethereum transaction hash
session = Confium::TC::FrostP256.start_session(
  coordinator: "custody.internal:7443",
  message: eth_tx_hash,
  algorithm: "ECDSA-secp256k1",
  quorum: { threshold: 3, total: 5 },
)

sig = session.wait_for_completion
# sig is a standard ECDSA signature — broadcast to Ethereum

Solana (Ed25519)

# Sign a Solana transaction
session = Confium::TC::FrostEd25519.start_session(
  coordinator: "custody.internal:7443",
  message: sol_tx_hash,
  algorithm: "Ed25519",
  quorum: { threshold: 3, total: 5 },
)

sig = session.wait_for_completion
# sig is a 64-byte Ed25519 signature — broadcast to Solana

Try the quorum playground

Drag the sliders to model any custody policy. The playground shows what happens when the threshold isn't met.

5
3
0 / 5 (need 3)

No signers yet — the signature cannot be produced.

Adjust N and T to model any quorum policy — 3-of-5 directors, 5-of-9 from 3 distinct regions, and so on. Confium's attribute-based threshold DSL expresses policies that the coordinator enforces at signing time.

Regulatory alignment

RegulationHow Confium helps
NYDFS BitLicense (US)Multi-party control over custody keys; structured audit trail.
MiCA (EU)Custody requirements for Crypto-Asset Service Providers; transparency log for accountability.
SOC 2 Type IIImmutable audit trail; attribute-based quorum; structured log for monitoring.
FinCEN Travel RuleTransaction-level signing records with signer identity + attributes.

Where to go next