A new blockchain protocol that has been in development for the past 18 months is ready for its public release.

The Silicon Valley startup Chain announced Monday that its Chain Open Standard 1, which it built with the help of nine major banks and payments firms, is now available to all financial companies interested in using blockchain technology.

The open-source technology was built to allow companies to run high-scale financial applications on permissioned blockchain networks. Chain claims it can finalize high volumes of transactions in less than one second.

Chain Open Standards also encrypts data for which it can provide selective read access to relevant counterparties and regulators and provides a smart contract framework that supports simple rule enforcement and key-value storage.

Capital One Financial, Citigroup, Fidelity Investments, First Data, Fiserv, Mitsubishi UFJ Financial Group, Nasdaq, State Street and Visa have been working with Chain over the last 18 months to help the startup develop and test the technology, called Chain Open Standard 1.

Some had already begun using the new protocol for their own internal projects, tests and research before Chain released it to the broader industry Monday.

Citi Ventures, Nasdaq, Capital One, Visa and Fiserv participated in a $30 million funding round Chain closed in September. Chain has raised $45 million in venture capital funding to date.