MPC vs seed phrase wallets
Seed phrase wallets back up everything in 12 to 24 words: portable and simple, but a single secret to lose or leak. MPC wallets split the key into shares held in different places and recover through cloud and biometric checks, while smart accounts use contract rules and multiple signers. None is risk-free; pick the one whose failure modes you can manage.
Four ways to hold a key
| Model | How it works | Examples | Main risk |
|---|---|---|---|
| Seed phrase (BIP39) | One phrase generates all keys; restore anywhere compatible | MetaMask, Trust Wallet, Phantom, Ledger, Trezor | Phrase lost, photographed or phished |
| MPC (multi-party computation) | Key shares are created separately and sign together without ever forming a full key | Zengo, Binance Wallet keyless mode | Depends on the provider's share and your cloud and email accounts |
| Smart account / multisig | A smart contract holds funds and enforces rules such as 2-of-3 signers | Safe, passkey-based smart wallets | Contract or interface bugs; network-specific |
| Card / chip backup | Key created on a secure chip and cloned to backup cards | Tangem | Losing all cards; trusting closed hardware |
Seed phrase wallets
Pros: an open standard, so you can restore in many wallets; no dependence on a company; works offline. Cons: one secret controls everything; people lose paper, store photos in the cloud, or type the words into phishing sites. Adding a BIP39 passphrase or using a hardware wallet reduces the risk. See seed phrase safety.
MPC wallets
MPC wallets never create a single complete key. Zengo says it uses two shares, one on your phone and one on its server. An encrypted copy of your device share is kept on Zengo's server, while the decryption key sits in your personal cloud account. Recovery needs your email, the cloud backup and a face scan. Zengo also describes a "guaranteed access" service run by independent companies, meant to keep funds reachable if Zengo stops operating (Zengo Help Center, checked Oct 2026). Zengo was acquired by eToro in April 2026 and remains a separate app (SpendNode, Apr 2026).
Binance Wallet's keyless mode splits signing authority across three shares, any two of which can sign (The Block Research, Aug 2026, a primer commissioned by Binance Wallet).
Pros: no paper to lose; a stolen phone alone is not enough; recovery feels like a normal app. Cons: you depend on the provider's infrastructure and continued operation; your email and cloud accounts become part of your security; it is harder to move to another wallet by "restoring" (you usually send funds instead); fewer independent audits than open standards.
Smart accounts, passkeys and EIP-7702
A smart account is a contract wallet. Safe lets you require, say, two of three signers, often hardware wallets held by different people. Some wallets use passkeys (the same Face ID or fingerprint login used by websites) as the signer. Coinbase introduced a passkey-based smart wallet option in 2024.
Ethereum's Pectra upgrade (7 May 2025) added EIP-7702, which lets an ordinary address temporarily act like a smart account. It brought new risks: Wintermute reported that over 80% of early EIP-7702 delegations pointed to copies of a single sweeper contract that empties wallets with leaked keys (The Block, Jun 2025), and ScamSniffer counted two August 2025 cases of malicious EIP-7702 batch signatures totalling $2.54M (ScamSniffer, Jan 2026). Only approve an account "upgrade" inside your own wallet's settings, never from a website.
Pros: flexible recovery, spending limits, multi-person control. Cons: chain-specific; contract and interface risk. The February 2025 Bybit theft of about $1.5B began with tampered Safe web interface code that made signers approve a disguised transaction (SlowMist, Feb 2025).
Card wallets
Tangem creates the key on the card's chip and lets you back it up to a second and third card, so there are no words to write down unless you choose its optional seed phrase mode. If you lose every card, you lose access. In December 2024 Tangem fixed an app logging bug that could write private keys into support logs for users who had created a seed-phrase wallet; it said no funds were lost (Cointelegraph, Dec 2024).
Which should you choose?
- You're organised and want maximum portability: seed phrase, ideally on a hardware wallet.
- You're afraid of losing paper and trust a provider: MPC, with strong security on your email and cloud accounts.
- Shared funds or large amounts: a multisig smart account with hardware signers.
- You want hardware without words: a card wallet with backup cards stored in different places.
Frequently asked questions
Is an MPC wallet safer than a seed phrase?
It removes the single-phrase risk but adds dependence on the provider and on your email and cloud accounts. It is safer for people likely to lose or leak a phrase, and less portable for everyone else.
What happens to my MPC wallet if the company shuts down?
It depends on the wallet. Zengo describes a guaranteed access service run by independent companies for this case. Check the wallet's documentation before depositing large amounts.
Can I export a seed phrase from an MPC wallet?
Usually not, because no single key exists. To switch wallets you normally send funds to a new address.
What is a passkey wallet?
A wallet, usually a smart account, that uses a passkey stored by your phone or computer, unlocked with Face ID, a fingerprint or a PIN, instead of a seed phrase.
Is multisig only for companies?
No. Individuals use 2-of-3 setups with hardware wallets in different places, so losing one device or having one stolen does not lose the funds.