@nitesh announced a wallet that he and Hampus have been working on that will use Second Labs new hash-locked Ark implementation, hArk.

As you may have read (#1420646), @supertestnet has some.concerns about hArk. He responded to Nitesh's announcement with this post:

source

Nitesh took the opportunity to write a thoughtful response:

I have been working on mobile platforms for a few years now and I know a thing or two about how they work.

Bitcoiners have high standards, which is a good thing but when it comes to mobile wallet UX, there are tradeoffs and I will have to make choices:

1. I could go live on mainnet with the current model of waking up devices on time and refresh them on the fly but what if devices don't wake up on time? What if they miss several ark rounds and vtxos expire? Now we trust the ark server to not sweep them because they absolutely can.
2. I have no control over how Apple APNS and Google's firebase works. You tell them to deliver a message and you pray they deliver (which they usually do) but then there are mobile OS'es. 5000 flavors of Android and the moody iOS. They behave differently in different circumstances and I have zero control over them.

Ask any dev who worked on non-custodial lightning on mobile (including me) and they will tell you the nightmare stories of how hard things are. Some users are willing to deal with all those issues and some won't.

And, me and Hampus built for both sets of users. There is Blixt wallet if you want to deal with all the problems but stay fully non-custodial. There is Noah if you're willing to accept tradeoffs. Both wallets will be maintained.

Even in lightning space, let's take phoenix for example, what is stopping them from broadcasting bad state of all their users because they track fully when a user last used the wallet and can easily steal funds from them. Plus their server is closed source and their wallet doesn't store state locally or atleast there is live sync to a remote database.

Noah's client and server is MIT licensed and will remain that way and I mentioned in the comments of the post that I will give the option to turn it off if any user wants to do on the fly refreshes or open the wallet manually and hit the refresh button.

Nitesh followed up in with a little more detail in response to another question from someone else:

The hArk model just needs 1 honest actor and it will work fine because it allows you to delegate trust to whomever you trust (it's not implemented yet, WIP)
But expired vtxos means the ark server is entitled to take the money. You would never want to be in that scary state.

I just don't want users to ever even think about refreshing or an emergency or anything. If you're someone willing to accept tradeoffs, just go into settings and turn it off.

You can't know if a wallet will sign "on time" because it depends on apple and google, not my server. Joining a round involves multiple back and forth signatures with the ark server and you have about 5s to wake up and do everything and go back to sleep. If you fail in the middle, you now broke the round for every single user, not just yourself. So an hour later, the ark server has to start over again. It will work fine if you have 5 users in a round. If you have 50, every round will just result in a failure.