Taproot, the first major overhaul to the Bitcoin protocol since Segregated Witness more than four years ago, is set to activate at block 709,632 this weekend. Enabled by Schnorr signatures and Merkelized Alternative Syntax Trees (MAST), Taproot will improve the efficiency and privacy of transactions, enhance scripting capabilities, and support Bitcoin scaling.
The Blockstream R&D team is one of the major contributors to the Bitcoin Core libsecp implementation and the related work on MuSig, both of which have Taproot support now integrated.
We have also taken the necessary steps to prepare our suite of open-source projects, products, and services for the ambitious upgrade, providing Bitcoiners prompt access to the benefits of Taproot at the time of activation.
Taproot Support
Taproot and its new address format, bech32m, will bring several benefits to wallets, including our industry-leading Bitcoin and Liquid wallet, Blockstream Green.
Green’s Multisig Shield scripts, particularly 2-of-2 CSV, leave a recognizable footprint on-chain. Once we make the switch to Taproot, they will be indistinguishable from any other Taproot output.
During the early stages of Taproot adoption, the anonymity set for UTXOs will not provide ideal privacy for end-users just yet. In the meantime, while the tooling gets refined and Taproot gains on-chain traction, we will add external bech32m support to increase the initial size of the anonymity set.
Green’s open-source and cross-platform libraries Green Development Kit (GDK) and Libwally will also be Taproot ready. This allows for other Blockstream products and services that use the libraries to support the upgrade, including the Blockstream Jade hardware wallet, Esplora, and Lightning implementation, c-lightning.
Users will be able to send to bech32m addresses on Bitcoin mainnet approximately one day (144 blocks) after activation on Green iOS and Android 3.7.6 and Desktop1.0.4. Both singlesig and multisig security options are supported.
Send support to bech32m addresses on Liquid will follow shortly in one of the upcoming app releases.
For a more in-depth explainer on what Taproot brings to layer-2 Bitcoin, read our Taproot article on the Blockstream Engineering Blog.
SPV Validation and Server Customization
Green iOS 3.7.6 now has SPV support for singlesig Bitcoin wallets, with support for multisig coming later. Note that Android has had SPV support since 3.7.2, and support for Desktop is in development.
Users can activate SPV validation from app settings, and the client will retrieve the block headers and proofs of transaction inclusion for the transactions in their singlesig Bitcoin wallets.
Another new feature available in the 3.7.6 release for iOS and Android is the ability to customize your electrum server for singlesig wallets. This feature allows you to point your wallet to your favorite server or personal node solution such as Raspiblitz, Umbrel, Nodl, Electrum Personal Server, etc.
Performance Improvements
Over the past many months, we have put significant work towards improving loading performances when logging in and navigating within the wallet.
This summer, we shipped app updates that improved the UX when navigating within the app, maintaining more state locally and diminishing the need to get updates from the backend, thus, reducing the loading times when navigating across accounts.
Since Blockstream Jade 0.1.27, we have made the Liquid master blinding key exportable from the HWW to the client so that unblinding transactions are much faster and do not require interaction with the hardware device for each call.
Under the latest version of Green, we continued to run even more state (e.g., balances, txs, UTXOs, memos) locally (and encrypted) after logout, requiring fewer data to be delivered to the clients and reducing overall login times.
“Green’s security model is preserved because of the encryption. Someone with physical access to the phone, even unlocked, could not decrypt any Bitcoin or Liquid data without succeeding at network login. Network login is a challenge-response protocol that will eventually lock you out, with server-enforced lockout after three failed attempts, so local authentication brute-force is prevented. Once locked out, you can only recover using your seed phrase.”
Adam Back, CEO at Blockstream
Green Resources
You can get started with Blockstream Green by downloading the apps for your preferred smartphone platform or operating system from the drop-down menu on our Blockstream Green page. The mobile app is also available directly on the App Store, Google Play, or F-Droid.
Should you have any difficulties and need support during the Taproot activation, please first check Twitter @BlockstreamHelp, and if there is no official announcement, we encourage you to submit a ticket on our Help Center.
Feedback and inquiries are also always welcomed on the Green Community Telegram.