Technology
MPC wallets: custody without a single private key
An MPC wallet replaces the seed phrase with cryptographic key shares. Multi-party computation lets a quorum of independent parties produce one valid signature while the complete private key is never created, stored, or transmitted — on any chain, at any point in the wallet's life.
How multi-party computation works
Multi-party computation is a family of protocols that let several parties compute a function over inputs none of them will reveal. Applied to a wallet, the secret input is the private key material and the function is the digital signature. Three phases matter.
1 · Distributed key generation
Each party generates a random share locally and the parties jointly derive the public key. The corresponding private key is only a mathematical implication of the shares — it is never materialised on any machine, so there is no seed phrase to steal, screenshot, or back up.
2 · Threshold signing
To spend, t-of-n parties exchange commitments and partial signatures over several protocol rounds. The output is a single standard ECDSA or EdDSA signature that the blockchain validates like any other. Parties below the threshold learn nothing usable, and no round ever transmits a share.
3 · Proactive resharing
Shares are periodically re-randomised so the same public address keeps working while every previously held share becomes worthless. An attacker must therefore compromise a quorum inside one refresh window, not merely over time.
MPC vs. multisig vs. seed-phrase wallets
| Property | Seed phrase | On-chain multisig | Threshold MPC |
|---|---|---|---|
| Full key exists | Yes, in one place | Yes, one per signer | Never |
| Approval enforced | None | On-chain contract | Off-chain cryptography |
| Gas cost | Standard | Higher per signer | Standard |
| Chain support | Universal | Chain-specific | Universal (ECDSA & EdDSA) |
| Signer changes | New wallet | On-chain transaction | Reshare, same address |
| Privacy of policy | n/a | Public | Private |
How CryptoMelon implements MPC custody
Every organization wallet is generated as a threshold key — 2-of-3 by default, up to 5-of-9 — with shares bound to operator devices and hardware security modules. Signing requests pass a policy engine before any MPC round begins.
MPC wallet questions
- What is an MPC wallet?
- An MPC wallet is a crypto wallet whose private key never exists as one whole value. Multi-party computation splits the key into independent shares held by separate parties or devices. A transaction is signed by those parties running a joint protocol, so the full key is never assembled — not during key generation, not during signing, and not at rest.
- How is an MPC wallet different from a multisig wallet?
- Multisig is enforced on-chain: the chain sees several addresses approving one transaction, which costs more gas and only works where the chain supports it. MPC is enforced off-chain in cryptography and produces a single ordinary signature, so it costs the same as a normal transfer and works identically on Bitcoin, EVM chains, Solana and TRON.
- Is an MPC wallet safer than a seed phrase?
- A seed phrase is a single secret: whoever reads it once controls the funds forever. With threshold MPC, an attacker must compromise a quorum of independent shares at the same time, and shares can be refreshed so old stolen shares become useless.
- What happens if one MPC share is lost?
- Nothing, as long as the remaining shares still meet the threshold. In a 2-of-3 setup any single share can be lost or destroyed, and a replacement share is issued through resharing without changing the wallet address.
- Which chains support MPC wallets?
- Threshold ECDSA covers Bitcoin, Ethereum and all EVM chains, BNB Chain and TRON; threshold EdDSA covers Solana. CryptoMelon exposes all of them behind one API and one control plane.
Run MPC wallets in production
Threshold custody, sub-address issuance and automated sweeps across BTC, ETH, BNB, SOL and TRX — from one API.