Last week we released Samourai Wallet version 0.96 that includes many improvements and fixes. However, we want to focus on two main areas in this post. One area you all have heard of and been asking for, and one we want to introduce you to.
Samourai Wallet has now fully integrated the changes needed to implement support for the latest bitcoin upgrade, Segregated Witnesses. By default all addresses you reveal through the receive screen will be P2SH-P2WPKH as defined by BIP141 and BIP49. We’ll refer to these as ‘segwit addresses’ for simplicity sake, but make no mistake, these are normal bitcoin addresses and are compatible with the Bitcoin reference client since version 0.6.0. These addresses are more efficient to transact with and users can expect to pay lower fees when spending from segwit addresses. Segwit support is enabled by default but can be disabled within the wallet settings or on a one-off basis with a convenient toggle switch directly on the Receive screen.
For the more technical users, your P2SH-P2WPKH and your P2SH inputs remain in a single HD account and can be mixed together in a transaction thanks to the wallet being able to sign mixed inputs. Your wallet will now have two Extended public keys (xpub) - so, if you are a Sentinel user you will need to add your BIP49 xpub along with your BIP44 xpub. Both of your xpub’s can be found in the settings. Samourai will manage the creation of either P2SH or P2SH-P2WPKH change outputs depending on the type of output being spent to. This is to decrease the fingerprint of the transaction on the block chain.
We’re happy to make public an initiative we have been thinking about for some time. Inspired by the Blockstream satellite and the 2003 essay by Nick Szabo, Advances in Distributed Security MuleTools is the umbrella term for the open repository of community ideas and open source code that promotes alternative routes for bitcoin broadcasts and block retrieval. Having many different options for interacting with the bitcoin network greatly increases the censorship resistance of the network and the financial autonomy of the user.
Samourai is interested in assisting with the development of any alternative paths for bitcoin pushTx and block retrieval and will consider all submitted projects for possible inclusion within Samourai Wallet.
Pavol Rusnak developed a simple PushTx server to push transactions to the bitcoin network via SMS and Andrew LeCody created a proof of concept APRS pushTx server for pushing transactions over shortwave radio. We think these both are a great example of an alternative method of pushing transactions. Inspired by the work of these developers, Samourai Wallet now includes the ability to export a signed raw bitcoin transaction hex or QR code that can be fed by the user to any pushTx server.
We look forward to exploring this concept further, hopefully with community feedback and support. Please feel free to check out the MuleTools readme, submit issues, ideas, pull requests, or documentation on the repositories. Any individual or company who wishes to collaborate is encouraged to reach out.