Samourai bitcoin wallet updates with Staggered Ricochet, UTXO tagging, and PayNym UX

Privacy specialized bitcoin wallet application Samourai announced today that update 0.99.05 is now available to update via Google Play for existing testers, install from Google Play for new testers, or build from source on Github.

The Samourai team informed they will be releasing a direct download APK including Stealth Mode on GitHub in the coming days.

apk hash sha-256 of version 0.99.05 : 6bc4ad679d041e9d172fc2d91818c9335c0832d591864b617ff3c8b1fe49144f

Staggered Ricochet

The anticipated and long-awaited upgrade to Ricochet is now implemented– a premium transaction designed to increase the plausible deniability of transactions by adding additional hops of history before the transaction reaches the final destination. The upgrade is called Staggered Ricochet and helps decrease the fingerprint of Ricochet use by hostile exchanges and coin scoring platforms (currently not a known threat, but certainly a possible threat). Staggered Ricochet works by following two simple rules.

• Rule 1 – Each Ricochet hop must be in a different block – Unlike a standard Ricochet which is broadcast using a time-based delay, a Staggered Ricochet will broadcast a single transaction hop per block. This means a Staggered Ricochet can take up to two hours before reaching the final destination (depending on the time variance of blocks discovered).
• Rule 2 – No transaction in the hop can be broadcast to the mempool at the same time – One of the clever ways of fingerprinting transactions that blockchain spies have been known to use is monitoring the mempool and using associated metadata including time first broadcast to assist in their address clustering heuristics. To help break that method Staggered Ricochet transactions will not be exposed to the public mempool until they are ready to be broadcast.

Staggered Ricochet is completely non-custodial, just like standard Ricochet (users can recreate the private keys of the hops at any time) and is available to enable for no additional charge to any Ricochet transaction.

Note: Staggered Ricochet will take significantly longer to arrive at the final destination, so time-sensitive transactions should continue to use standard Ricochet.

PayNym Helper Actions

A featured benefit of using Samourai’s PayNym technology is the reliable way to avoid reusing addresses (a privacy concern) with the ability to cryptographically generate addresses on behalf of a counterparty without needing to communicate with them (a user experience concern).

“Pay Again”

For outgoing PayNym transactions from a wallet – transactions a user has sent – they will be able to initiate direct payment to the wallet with the address pre-filled. Users can see how this type of functionality can be developed to encompass reoccurring non-custodial payments without impacting your privacy.

“Refund”

For incoming PayNym transactions into a wallet – transactions a user has received – they will be able to initiate a return payment back to the sender wallet with the amount and address pre-filled. Users can see the power such a feature can enable with a little development, especially for dynamic street merchant use.

UTXO Tagging and Whirlpool Prep

Samourai also added the ability to tag any UTXO with a custom value. This can be useful for noting UTXOs that users may want to avoid spending, or the need to add any additional metadata. These tags are local and will be lost if a user restores from the mnemonic + passphrase, so users should restore via their automatic encrypted backup whenever possible. Users can currently tag UTXOs from the Unspent Output list and will be expanded upon in the next updates.

For TestNet users: Samourai has added in PSBT support to complement upcoming Whirlpool mixing and other post-mix transaction types such as 2-Person STONEWALL and Stowaway. Bleeding edge testers will be able to manually compose collaborative testnet Stowaway transactions using the tools found in Settings. The team anticipates advancing this to MainNet in the next releases.