- Samourai Wallet, what it does
- a little note about Sentinel
- Xapo - dynamical addresses and pooling
If you have enough bad luck to have been at the epicenter of political debates concerning censorship in North Korea chances are you have spotted a post uncovering transactions made from a Bitcoin wallet designated for marketing expenses.
From the point of a practical user who is not naive enough to be surprised by cheating, unfair behavior or manipulation this situation is very unsettling. It looks like linking your wallets to Bitcoin exchanges, gambling sites and Darknet is surprisingly easy with a tool called Wallet Explorer. Basically, once you tell someone your Bitcoin address (if you have a steady single address) you are potentially exposing yourself to dox for any time in the future.
Even if you think you have nothing to hide: It is better to avoid this machinery in case you have some reputation in the community. Misinterpreting information right before everyone’s eyes is not as difficult as tender-hearted geeks tend to imagine.
Luckily services are emerging out there to help you keep a little more anonymous.
Samourai is the Bitcoin wallet for the streets.
The “About” section states: We are privacy activists who have dedicated our lives to creating the software that Silicon Valley will never build, the regulators will never allow, and the VC’s will never invest in. We build the software that Bitcoin deserves.
That pretty much sums up the positives of Samourai wallet. The negatives being only the fact that the app is still being tested.
With Samourai you hold your own keys, you have a secure pin access and your activity is encrypted using AES-256.
Your wallet doesn’t have a single given address. It reuses addresses transaction after transaction.
In addition, Samourai will randomize the number of change outputs for each send. It also has a few other policies to make sure figuring out the wallet address metadata gets difficult.
- There are three obfuscation levels available for each transaction, the highest one making the transaction look like a CoinJoin payment on the blockchain (that is, well mixed)
- From Bitcoin Wiki: “A coinjoin transaction is one where multiple people have agreed to form a single transaction where some of the the outputs have the same value. A casual observer of the blockchain cannot tell which output is of interest to each sender.”
Samourai wallet only can hold Bitcoin but offers instant conversion into Dash and other altcoins.
- You can restore or wipe out or destroy the wallet remotely by sending a text message
Jan/Feb 16: Samourai wallet is not ready to go public yet but you can sign up as a alpha tester and download the Android app on GooglePlay.
Side note: Sentinel
Since this article will probably be of use mostly for people who care about security, it might be good to mention one more product made by the creators of Samourai wallet. It is called Sentinel and it comes handy if you have an offline wallet.
You might be using Armory offline wallet (or other wallet) for cold storage. If you have it in offline mode, it can receive transactions that you can monitor from an online device with check-only wallet. Sending transactions is a little more tedious.
Sentinel is an app that makes it possible to gather all your offline wallets and check them in one place.
It never asks for your private keys so you don’t even take a leap of faith to use Sentinel.
Another option is getting a wallet on Xapo, you have to confirm your identity to use it though. However the company is based in Switzerland. A country with good tradition in keeping private things private.
What Xapo does is it not only creates addresses dynamically. The reason is, once someone knows the address your wallet can be looked up anyway, even if you will not use the address again. Because of that Xapo does a step two as well.
Xapo: The second step involves pooling your wallet funds. As soon as funds arrive to your bitcoin wallet address, we move those funds to a common pool. This prevents anyone from going to the blockchain and seeing the amount of BTC in your addresses or discovering where your are transferring them from. Since the funds are pooled amongst other individuals funds, it is extremely difficult for someone to identify specifically where the original funds that you received were sent from.