We are very happy to announce the release of Samourai 0.98.5. This update is filled with new functionality and improvements, so let’s get right into it.
Full bech32 support
Bech32 is the native way of encoding segwit bitcoin addresses. Samourai Wallet is now fully compliant with BIP84 - which means you are now able to send externally to bech32 encoded addresses as well as receive to your own bech32 encoded addresses. A bitcoin address encoded with bech32 starts with bc1 and is not backwards compatible with older/unmaintained software and wallets. It may take a while for bech32 support to fully roll out across other wallets and services. For this reason, your Samourai wallet will still generate segwit addresses that are backwards compatible with all bitcoin wallets (these addresses start with a 3) by default. You can easily reveal a bech32 address directly from the wallet Receive screen.
Introducing Boltzmann and STONEWALL
Since December 2017, when Samourai acquired the OXT block exploration platform, we have been working closely with OXT privacy and fungibility engineers to audit the transactions that Samourai Wallet creates, looking for fingerprints and metadata that could be extracted from public transaction data by blockchain analysis companies. One part of this audit process involves running transactions through a script called Boltzmann - Boltzmann returns the entropy of the transaction which measures the linkability of inputs to outputs of a given transaction by determining the number of individual mappings of the inputs to outputs used in the transaction. The higher the entropy of a transaction, the more resistant to address/identity clustering techniques used by Blockchain analysis companies - as the element of doubt connecting ownership of addresses by any entity is too great, and may pollute the entire cluster.
As part of the ongoing audit we identified a potential shortcoming which may lead to less entropy than expected when sending via BIP126. BIP126 was inspired by the Samourai Alpha 1 “decoy change addresses” feature and introduced refinements to improve efficiency of the feature. As our understanding of the latest analysis techniques further evolves, the need to stay on the cutting edge of careful coin selection and transaction manipulation increases in importance.
As such, we are retiring BIP126 from Samourai Wallet and we are happy to introduce STONEWALL in replacement.
STONEWALL is a new send type available at no extra charge to all Samourai users, enabled by default - it can be disabled in the Transaction Settings. Whenever possible your wallet will create transactions that simulates a CoinJoin transaction and obtains a Boltzmann score greater than 0. Transactions will appear on the blockchain as if there are multiple unrelated counterparties involved. STONEWALL improves on BIP126 in a number of ways. Primarily, STONEWALL activates more frequently than BIP126 did, meaning more of your transactions will benefit from this type of protection. Additionally, the entropy of STONEWALL transactions have been consistently higher than BIP126 transactions during our testing. Specific STONEWALL Algorithm information can be reviewed here.
Samourai is committed to continuing the investment and development of STONEWALL, Boltzmann and other open source research and development projects maximising privacy and fungibility of bitcoin users. Samourai users will see further integration with Boltzmann in the near future, including the ability to measure the entropy of transactions before they are broadcast directly in the wallet. You can review the entropy of your bitcoin transactions today by searching for your transaction using the OXT Block Explorer. We look forward to polluting the datasets of blockchain analysis companies and stone-walling their efforts to debase the fungibility of the bitcoin token and the privacy of the bitcoin user.
Ricochet is one of our most popular features, and with good reason. Ricochet provides a good layer of protection from “blanket blacklists”. Blanket blacklists are a very primitive - and stupid - form of blockchain analysis relied upon by many exchanges that deal with Fiat currency. The blacklists are informed by looking at the “history” of coins going back 4-5 hops, and marking those coins “High risk” if someone at some point in time did something the company ‘analyzing’ disagrees with. This form of blanket blacklisting results in many innocent users having their accounts shut down for seemingly no reason. Ricochet adds additional “hops” of address history between your initial sending address and the final destination address. Today we are happy to announce that we have updated Ricochet to use native segwit bech32 addresses for all the hop transactions. This results in lower total miner fees for Ricochet users.
Ricochet users who have taken the additional step of connecting to the Samourai Donations PayNym will see increased privacy benefits when sending via Ricochet with the introduction of a new algorithm that reduces the fingerprint of the ricochet transaction on the blockchain. It is highly encouraged to connect to the Samourai Donations PayNym for a big Ricochet privacy boost and enhanced protection from blanket blacklists.
Stability and Android battery warning
Last but not least, we have made many modifications to the underlying Samourai architecture to improve the stability of the wallet. Specifically, loading times and the responsiveness after sending and receiving should be improved for all users.
Due to recent changes in Android 8, some users were impacted by force closes and general stability issues. This update includes significant refactoring of core services, which should clear up a lot of issues Android 8 users were experiencing.
Another Android 8 specific issue is a persistent (and incorrect) warning that Samourai is using too much battery impacting some users. This is again due to changes in Android 8 which target background services. We are making the needed changes as requested by the new Android guidelines, but they will not be ready until the next update. You can confirm the battery warning is erroneous by viewing more details and verifying the battery usage amount since the last full charge of the device.