Google pitches banks crypto custody that splits keys, eyes 2027 launch

Google Cloud has unveiled Multi-party Compute (MPC), a custody service that breaks a crypto signing key into separate shares held in different places so no single party controls the whole key.

The product is being pitched to banks, and Google says that the commercial launch will come in early 2027.

How does Google’s key-splitting work?

In the crypto space, whoever holds the private key controls the assets. However, that setup has also posed a problem that has long troubled institutional custody, and that is the fact that storing that key in one place makes it a single target.

MPC was built to solve that very problem, as it avoids assembling a full key in the first place.

Google Cloud’s documentation says that the service uses threshold signing that is built on a hardened version of the DLKS23 protocol.

Each hardware-backed party generates and keeps its own isolated share.

A valid signature gets produced through a joint protocol. When an attacker compromises some of the parties but does not meet the set threshold, they will not be able to forge a signature or rebuild the key.

The shares can be kept in different environments. A bank, for example, could keep one share on its own hardware, another in Google Cloud, and a third with a separate provider.

MPC has support for ECDSA on the secp256k1 curve, which covers Bitcoin, Ethereum and EVM-compatible chains. Google Cloud stated that support for EdDSA on Ed25519 for Solana will be coming soon.

Who is already testing Google Cloud’s MPC platform?

Several financial institutions as well as design partners are already testing the product.

Google laid out the premise of the service and what it can do for institutions at its digital-asset security symposium that was held in New York on Wednesday, October 28.

Present at the event were representatives from banks such as Morgan Stanley, Citi, and Wells Fargo, and crypto exchange OKX, among others.

The product sits in private preview, which Google offers “as is” with potentially limited support. A company spokesperson reportedly said that they expect to make the MPC Key Management Service generally available in early 2027.

Alphabet, Google’s parent, has started using the technology to secure its own holdings on Solana and Ethereum.

This follows Google Cloud’s earlier push into financial plumbing with its Universal Ledger layer-1 blockchain, aimed at bank payments.

Why private-key theft makes the timing matter

Chainalysis found that private key compromises were responsible for around 43.8% of all the crypto that was stolen in 2024, with the total theft that year around $2.2 billion.

So far in 2026, over $2.37 billion has been lost to crypto hacks, according to DeFiLlama data on hacks and exploits, and private key compromises have been responsible for close to 5% of those losses. In fact, key-related compromises have been responsible for a total of over 26.4% of the losses recorded this year.

With MCP, the single-point-of-failure risk is removed, as it ensures that compromising one system is not enough to move funds.

Quantum security is on the roadmap, not solved

Google is also a large quantum-computing developer, and the current MPC product is not a post-quantum solution. For now, its focus is on stolen credentials and unauthorized transactions and preventing that.

However, the company has said the architecture could later take on post-quantum cryptography.

Google Cloud’s own research has suggested in the past that Bitcoin’s cryptography could be broken with far fewer qubits than once assumed, so it comes as no surprise that the company will be preparing to mitigate the numerous events that will likely occur in a post-quantum world.