Google Cloud details MPC service for institutional Bitcoin custody

Google Cloud detailed its preview Multi-party Compute service for institutional Bitcoin custody in documentation updated on Monday. The product is currently in private preview with several financial institutions, and Alphabet has started using the system to secure its own assets. The service divides signing keys into fragments held by separate parties or machines, requiring a set number of fragments to sign a transaction. Institutions can configure thresholds such as two-of-three or five-of-seven for signing transactions. A policy engine running inside Google's Confidential Space checks transfers against limits, destination restrictions, and approval rules before any signature. Google states it has no access to key shares in unencrypted form.

The MPC Symposium featuring Google Cloud took place on Wednesday in New York. Speakers at the symposium included representatives from financial institutions such as Morgan Stanley, OKX, Citi, and Wells Fargo. Google previously explored related technology through Confidential Space, a cloud environment designed for secure multi-party computation. On October 1, Google expanded its Bitcoin security rules to evaluate transaction amounts, identify destination address types, and detect change outputs. Google plans commercial availability of the MPC service in early 2027.