The team of Samourai Wallet, a privacy-enhanced bitcoin wallet app today announced some new functionality and improvements in their latest release available now on Google Play. First off, Samourai Wallet is now fully compliant with BIP84 – which means users are now able to send externally to bech32 encoded addresses as well as receive to their own bech32 encoded addresses.
A bitcoin address encoded with bech32 starts with bc1 and is not backward compatible with older/unmaintained software and wallets. Just a couple of other wallets have added bech32 support and will take some more time to fully roll out.
A couple of other enhancements to the wallet are noted below:
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.”
Retiring BIP126 from Samourai Wallet and introduced 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 a user wallet will create transactions that simulate 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 transactions will benefit from this type of protection. Additionally, the entropy of STONEWALL transactions has been consistently higher than BIP126 transactions during the team’s testing.
Ricochet is one of the most popular features of the Samourai app. Ricochet provides a good layer of protection from “blanket blacklists”. Blanket blacklists are a 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.
As of now, the app has an updated Ricochet to use native segwit bech32 addresses for all the hop transactions. This results in lower total miner fees for Ricochet users.
The Samourai team also made many modifications to the underlying Samourai architecture to improve the stability of the wallet. Specifically, loading times and 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 new update includes significant refactoring of core services, which should clear up a lot of issues Android 8 users were experiencing.