S5 E2: Leo Wandersleb on WalletScrutiny & Why Samourai Isn’t That Great

Leo Wandersleb, lead developer of Mycelium Android wallet, has an unusual yet useful fascination with open sourceness and verifiability. In his quest to understand how Bitcoin wallets work, he sought to take “Don’t trust, verify” motto to the absolute limits.

Call it community service or selfish attempt to analyze Mycelium’s competition, but his website WalletScrutiny.com is an incredible resource to better understand how some of the most popular mobile wallets in the Google Play Store (Android) work.

In a nutshell, the Wallet Scrutiny tries to answer the question “How likely is it that the developers of this wallet are malevolent and can steal my bitcoins with sneaky code inserts?”.

For the sake of determining the quality and security of mobile wallets, Leo Wandersleb has created a 3-step process:

  1. At first he looks at the custodianship of the wallet. If users manage their own private keys and don’t require to trust a third party, then the wallet is non-custodial and therefore better for financial sovereignty.
  2. Then he checks to see if the wallet is open source. If there is a public repository which contains all the files that can also be downloaded from the Google Play Store, then the security potential of the wallet is greater. However, open source does not always mean secure or properly audited.
  3. Finally, he compiles the app from the source code to see if the result is the same as what you can download from the Google Play Store. Sometimes the repositories are not properly maintained and significant differences can be found – which is a red flag that means that the developers are either negligent or have something to hide in their releases.

On the basis of this process, Wandersleb has created 4 categories of Android BTC wallets:

  • custodial (Coinbase, Abra, Xapo, Luno, Bitrefill, Wallet of Satoshi);
  • closed source (Coinomi, Trust, Jaxx, Guarda, BitPie, Magnum);
  • open source but not verifiable (Blockchain, BRD, BitPay, Edge, Samourai, Blue, Phoenix, Zap, Lightning Labs);
  • verifiable (Blockstream Green, ABCore, Schildbach, Airgap Vault).

This episode offers more details about various wallets and their review process, and a significant amount of time is dedicated to discussions about Samourai Wallet – a popular privacy Bitcoin wallet which somehow fails the verifiability test in spite of multiple requests to publish the necessary code.

Listen to Leo Wandersleb on iTunes & Spotify!

Time Stamps:

00:46 – Introduction

02:15 – Categorization of mobile wallets on WalletScrutiny.com

3:50 – What verifiability means for wallets, and why verifiable does not mean verified

6:40 – Why verifiability matters to make sure that the wallet developers are not hacking you

9:40 – Which wallets are listed as verifiable on WalletScrutiny.com?

12:20 – Why Coinomi wallet is not open source

13:05 – Coinbase is custodial and should be avoided

15:21 – Some of the most popular mobile wallets also happen to be the worst

18:25 – Wallets that are popular, open-source, but not verifiable 

19:08 – Samourai Wallet is not verifiable

22:10 – How reproducibility works at MyCelium to prevent abuses by release managers

24:20 – More arguments against Samourai

29:20 – Android’s interesting security

31:27 – Google Play vs F-Droid

33:55 – What about iOS wallets, are they verifiable? 

35:20 – Blockstream Green and why it’s great

37:20 – Coinbase vs Samourai for the average user

40:30 – Why it’s better to be careful with mobile wallet updates

45:40 – In the “Don’t trust, verify” issue, what can the average user actually verify?

48:40 – Leo fails at marketing his own project

50:40 – Why builders are the best

51:10 – Companies exploiting the ignorance of newbies 

53:00 – Satoshi was honest about Bitcoin’s limitations 

55:30 – Why MyCelium’s iOS wallet is terrible and not recommended, but the Android version is better

59:10 – MyCelium vs Blockstream Green 

1:00:30 – Collecting fees from routing Lightning Network transactions

1:02:48 – Lightning Network Routing

1:06:00 – Best mobile wallet for ease of use and open source verifiability 

1:09:00 – Wallet Scrutiny [dot] com and its methodology 

1:10:30 – How much does reputation matter in the Bitcoin space?

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Vlad Costea

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