Bitcoin transactions are complicated: its UTXO digital currency model, transaction formats, and key types—not to mention its new and exciting applications—mean that signing transactions and managing assets can be daunting! In fact, most key management providers who claim to support Bitcoin only support basic transfers—meaning they don’t provide the necessary functionality for you to participate in next-generation Bitcoin protocols. <br> We’re excited to announce that, beyond sending and receiving assets (which other providers often support only for Legacy or SegWit keys), CubeSigner now offers comprehensive key management for Bitcoin, including full support for the latest SegWit and Taproot standards and a native API for Partially Signed Bitcoin Transaction (PSBT) signing. These features are necessary for participating in upcoming BTC staking protocols, for example, and for building secure and efficient liquid staking protocols on top of them. <br> In short: if Bitcoin supports something, CubeSigner now does, too. <br> ## Bitcoin is *not* stagnant. Key managers are… <br> The perception has long been that Bitcoin is stagnant compared to the vibrant, fast-paced world of DeFi. This is not true! The last few years have seen significant innovation on the core protocol—and in most cases, custodians and key management products simply haven’t kept up with these new developments. One reason they’ve fallen behind is that much of this innovation takes advantage of new cryptographic primitives, which means that keeping up is *hard*. In contrast, much of the innovation in other ecosystems is further up the stack, leaving core cryptography almost untouched. [^eth] <br> Unfortunately, lack of modern Bitcoin support has become an emergency: the next generation of Bitcoin protocols—for example, Babylon—rely on recent (and exciting!) cryptographic developments. In plainer terms, if your key manager doesn’t support PSBTs, Taproot, or adaptor signatures, DeFi’s newest frontier is simply out of reach. <br> ## CubeSigner: rocket fuel for your Bitcoin future <br> We’ve put in a lot of effort leading up to this release of CubeSigner as a one-stop shop for Bitcoin key management and signing: key generation, safety policies, authentication, access control, and a full-featured transaction API. CubeSigner has long supported SegWit; with this new release, you can also use CubeSigner to sign (more complex) transactions with Taproot keys. The newly released APIs also save manual work: we’re psyched to watch developers use their favorite libraries for crafting PSBTs that use arbitrary spending conditions—including the spend scripts required by the latest Bitcoin-based protocols (e.g., to manage staking deposits on Babylon). In the next few days, we’ll share a post on how to make this *even easier* with our native, protocol-specific APIs. <br> Beyond feature-complete functionality, CubeSigner gives you ironclad security. Protect your BTC—and your users’ BTC—by controlling both the kinds of transactions and the circumstances under which Bitcoin keys can sign. Most teams use multi-party approvals–requiring K out of N parties to approve a transaction (e.g., using a YubiKey) before signing—as a baseline security policy. Many go a step further and layer multi-party approval with other policies to, for example, allowlist recipients and/or limit the maximum value spent over a given timeframe. The result is that funds are protected even if machines are compromised. <br> As one final example: CubeSigner also lets you lock down your Babylon staking setup. In particular, we’ve launched a full suite of functionality related to deposits. We’ll have more details in a future post, but as a sneak peak: CubeSigner policies make it possible to control everything from the staking amount to the withdrawal address. <br> <a href="https://x.com/cubistdev" target="_blank">Follow us on X</a> to catch our next post detailing new CubeSigner features for Babylon staking. <br> ## Bitcoin 🤝 DeFi <br> We’re thrilled to be in the trenches with the teams building Bitcoin’s DeFi future. With CubeSigner’s comprehensive Bitcoin support, we’re simplifying and securely connecting Bitcoin to the rest of the DeFi ecosystem. <br> Interested in trying out CubeSigner for Bitcoin signing? <a href="https://cubist.dev/contact-form-cubesigner-hardware-backed-key-management" target="_blank">Get in touch here</a>. <br> <br> [^eth] <small>One notable exception is Ethereum’s transition from proof-of-work to proof-of-stake, which introduced a new protocol (with new key types) for validator signing. And to our knowledge, CubeSigner is also the only key manager with robust support for Ethereum validator signing!</small><br> <br>