Google Cloud details shared-signature crypto custody, still in preview

An institutional offering that remains in preview

Google Cloud is detailing Multi-party Compute, its platform for protecting keys used to sign digital-asset transactions. The service is being discussed around the symposium held in New York on October 28, 2026. In an update published on October 29, Cointelegraph reports that a Google Cloud spokesperson targets general availability in early 2027. That announced timetable remains a goal: the official documentation reviewed still classifies the product as preview, supplied as is and with potentially limited support.

The distinction matters to institutions evaluating custody infrastructure. A technical presentation and trials do not mean a service is already open to everyone under the terms of its future commercial version. The documents describe a signing and governance platform, rather than a consumer wallet to install. On their own, they also do not constitute regulatory authorization to hold customer assets in every jurisdiction or a guarantee against every form of fraud.

Producing a signature without assembling the complete key

The mechanism relies on threshold signatures. Independent participants, backed by secure hardware, each generate and hold an isolated share of the secret. They cooperate to produce a valid signature without assembling the complete private key in a single location. According to Google, compromising fewer participants than the required threshold does not allow an attacker to forge that signature or reconstruct the key. Service continuity nevertheless depends on enough participants remaining available to meet the threshold.

The documentation lists ECDSA signing on the secp256k1 curve, used notably by Bitcoin, Ethereum and EVM-compatible networks. Support for Ed25519, associated notably with Solana, is marked as coming soon. It is necessary to distinguish the current version's documented capabilities from possibilities envisaged for later availability. Technology designed for several blockchains does not mean every network, operation and signing mechanism is already offered under the same conditions.

Internal rules guide signers without locking everything down

The system distinguishes administrators, policy authors and signers organized into teams. Policies specify share holders, participation thresholds and storage locations, for example in the cloud or on customer premises. Address lists and transaction rules can also define destinations or limits. These functions organize internal responsibilities; their presence does not relieve an institution of carefully choosing its permissions, participants and recovery procedures.

One limitation deserves close reading: an automated transaction-policy verdict guides signers, but is not an irreversible veto. The documentation says a denied operation can still be executed if enough signers approve it. Security therefore also depends on human governance and participants' actual independence. Before the announced general availability, institutions will need to examine those settings and service conditions, rather than equating a distributed key with a complete absence of risk.