Square open sources its bitcoin cold storage solution

The mobile payments company announced that the documentation, code, and tools for its "Subzero" Bitcoin cold storage solution now available via its GitHub. Users of Square's Cash App can buy, sell, and withdraw bitcoins from their accounts. Square leverages Subzero to store the bitcoins that it manages. One of Subzero's unique features is a customized implementation that only allows Square's cold wallets to send funds to a Square-owned hot wallet. Additional features include a multi-party singing ceremony that requires multiple parties to sign a transaction before bitcoins are released from a wallet. Furthermore, Square also open-sourced its "Beancounter" tool that audits wallet balances and can compute the balance of a wallet at any given date in the past. (Source: Square)