Bitcoin Forum

Is it possible? I want to raise the discussion. Really want to know more on this issue as it should be pretty exciting if it is possible.

Yes it's possible and it already exists. You can perform a search for 'ABcore' by Greenaddress. It supports running a lightweight Bitcoin core full node on your powerful mobile devices. It has been compiled using dependencies from Arch linux and works on both x86 as well as x64 bit android devices. You'll however require a powerful smartphone with a fast processor and something with large amounts of RAM (about 3 GB)

It is actually a great thing if it already exists, to have a cold wallet in your smartphone to always keep your coins with you wherever you go, without any worries at all.

Thanks. Good information. Is it only with bitcoin core people are really 100% control the bitcoins? I am still confuse. Others like the mycelium wallet, do we really controlling the bitcoins?

i cant see how this is possible  ??? where does the app store the nearly 90GB of data that is the blockchain ?


a cold wallet cant be a cold wallet on a smart phone, if it is connected to the internet.

In my country, the data costs on mobile phones are very expensive, so wasting the bandwidth to run Bitcoin Core on a phone would not

be worth it. You would also have to use a pruned version of the Blockchain, because the full Blockchain would never fit on most smart

phones. A Wifi connection to your home broadband, could possibly be a option, but why would you do that, if you did this to be mobile?

A wallet on your phone is NOT "cold".  It appears that you do not understand what the words "cold wallet" mean.


No. It is not necessary to use Bitcoin Core to be 100% in control of your bitcoins. As long as you have exclusive possession of the private keys, you are 100% in control of your bitcoins.


Yes.  As long as you properly secure access to your wallet and your backups, you are really controlling your bitcoins with wallets such as Mycelium, Electrum, Multibit, Armory, etc.

guys, it is a lightwallet... not a full node.
and if you need a wallet, well, there are some good option online like xapo. if you dont trust these services just dont put much money there. it's ok for daily usage.

If this can be seen in the next few years then i could proudly say that the bitcoin dominance is really getting bigger.  Then this would surely be a good start since that android is made by linux core system then virus is really not possible well correct me if im wrong

I'm not entirely sure what the thread opener means with "Bitcoin core software". Maybe he/she is referring to running a Bitcoin wallet of some sort - that of course if not a problem at all. There are numerous Bitcoin apps.

However these apps are not full Bitcoin clients. Running a fully validating node, coming with the whole blockchain - the reference implementation "Bitcoin Core" - is certainly not possible using today's smartphone technology. Both memory and CPU usage of Bitcoin Core require a desktop PC or laptop. Also bandwidth use would be too excessive for most mobile carrier contracts - not mentioning that you would need to install a new OS on your smartphone.

I also doubt that Bitcoin Core will run on smartphones in the foreseeable future, because hardware requirements for the software are likely to grow faster with increased use of Bitcoin than hardware progress for smartphones.

ya.ya.yo!

You are wrong.

Consider yourself corrected.

Even if a pruned version of the Blockchain is stored somehow on smartphones this won't alleviate the issue of downloading new chunks of data every single day because there are constant updates to the Blockchain. And every time a phone tries to connect it would be out of sync and would need to download the new data before it could move funds I guess so in the end it's a lot of hassle to even bother with something like this when dedicated lightweight mobile Bitcoin wallets already exist.

Holy moly. Have you never checked the news? There's lots of nasty things out there looking to get at you. I think it does depend on how slack you are with what you download into it but it is very possible.

This is my first time that there is a software for smart phone that you can install bitcoin core since the whole block chain is big..
And i think it can destroy our phone.

I've no idea whether such a thing exists, but you could easily fit it on a 128gb sd card. I've no idea whether a phone could cope with the indexing. You'd need one monster of a data package too. It seems overwhelmingly pointless to me.

(Quote from DannyHamilton:
Yes.  As long as you properly secure access to your wallet and your backups, you are really controlling your bitcoins with wallets such as Mycelium, Electrum, Multibit, Armory, etc.)





That means if mycelium collapse like mtgox and bitfinex, we will not lose our bitcoins?

For mycelium, I only know how to 'login' using the 12 words mnemonic, or just create a new wallet every time I use, but don't know the technical things to deal with the keys.

I always thought electrum and the other wallets like online exchanges. I guess i was wrong?

I would prefer paper wallets over those to be honest.

1st choice: Core wallet
2nd choice: Paper wallet
3nd choice: Electrum and the others...

That's trust my list.

And, i would like to run my core wallet in my phone put it takes so much space so it is pointless i guess.

Correct.


The 12 word mnemonic is a seed that is used by the wallet to generate all the necessary keys.  If someone gains access to the data stored by Mycellium on your phone (virus, malware, steals your phone and password, etc), they can take your bitcoins.  If someone gains access to your 12 word mnemonic then they can take your bitcoins.



You were wrong.  Electrum and the other wallets are software that you run on your own computer (or phone).  The software provides you with your own bitcoin addresses and requires you to secure your own private keys against loss or theft (just like Bitcoin Core).  There is nothing magical about Bitcoin Core that makes it any more or less secure than any other well maintained and well reviewed open source wallet.  There is nothing "official" about Bitcoin Core.  It is just a piece of software written by a group of developers that have given their client a fancy name.


That's just silly.  Paper wallets have a completely different purpose than software wallets.  That's like saying I'd rather put my $20 bill in my safe in my house instead of in my wallet in my back pocket.  Sure, it might be "safer" locked in a safe (depending on how you secure the safe), but it's a lot more difficult to use when you are at the store and want to buy something.

I'm reminded of when some kid said to me "700MHz? You can't even use that much CPU for anything"

In 2026, when people are streaming 3D video on their phones from the summits of mountains, running Bitcoin Core isn't going to seem so outlandish. We're not quite there yet, but only 2 things remain in the way: mobile CPU single thread performance and data prices. Every other performance bottleneck is gone on a 2016 phone.

The constant read/write of the application would likely just shorten the lifespan of the SD card significantly at the very least. The initial synchronization could take quite sometime. The CPU in phones are designed with low TDP and passive cooling in mind. The synchronization speed might have to be slowed down quite a bit to fit in.

If you really do not want to trust the servers ran by the wallet developers, you can setup the Bitcoin Core yourself and connect your wallet exclusively to it only. In that way, your privacy wouldn't be compromised and there is next to no security risk.
Mycelium is similar to Bitcoin Core in a way that both of them give their users the control of their private keys. Bitfinex, coinbase and xapo are online wallets and they HAVE the knowledge of what your private key is and can steal your Bitcoins anytime. The key difference is that Mycelium does not offer a desktop version and is not a full node. Mycelium perform a simplified verification on the blocks by only checking the merkle root. Hence, they need to trust the peers that they are connected to. If Mycelium cease to exist one day, which I consider to be quite impossible, you can easily use the previous version to import the mnemorics and retrieve your addresses back. You can do it yourself by following their extraction path too [1].

[1] http://support.mycelium.com/hc/en-us/articles/206362319-Hierarchical-Deterministic-Wallets

Has anyone gotten this to work? Couldn't figure it out.

Can you imagine a PDA running a bitcoin software? I mean, did a software like this ever existed?
Or maybe for a Blackberry?
Just asking:)

It's possible, however impractical. You really don't want to store 100+gb of the blockchain on your phone. Just use an spv client like Mycelium.

Yes. Mycelium can insert a backdoor in which they transmit the information to their own server after the user generates the seed. There is also a possibility that they have a predetermined list where the seed is generated, weakening the randomness of the seed.

This can happen to every Bitcoin wallet. That's why they are open sourced. Users can verify the source code and ensure that no suspicious or malicious codes are added in. They can compile it themselves and ensure that there is no backdoors. As far as I can tell, Mycelium is relatively safe.

So, why we are 100% controlling the bitcoin when using Mycelium, when comparing with bitcoin core?

Both wallets mean that you are 100% in control of your Bitcoin because the private keys are in your possession. The "vulnerability" is just that the developers could in theory insert a backdoor, but this can happen with any wallet.

How to deal with the private key in Mycelium? Are there any details instruction?

They are all handled internally by the wallet. You do not need to worry about that.

Mycelium uses BIP39[1] seeds to generate addresses. This means that the addresses are all generated from the seeds and hence, the user only need to have the seed and all their address can be recovered through that. Even though you can extract the private keys from the seed by using their BIP39 deviation path, I won't recommend this.

[1] https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki

Yes it is possible. There are some considerations, though.

Currently to sync to the network, 10s of GB (80?) of disk space is required for a full node (soon to be >100 GB). I will not discuss SPVs here since they are a poor solution relying on trusted 3rd parties.

The actual space consumed is not so much of an issue (I'm not talking about Moores Law that the hard of thinking espouse, either) but the 10s of GBs do still need to be downloaded even if not stored. Many mobile packages (99% in my country) limit the bandwidth to a couple of GB per month so it becomes almost impossible to sync. Unlimited bandwidth mobile packages are required and these are like rocking horse droppings and far from cheap.

Assuming that one has already synchronised, then things become easier. A block is created approximately every 10 minutes and is about 1MB. That's about 144MB per day (~4.3 GB per month). Still. These plans are quite expensive and if one is also an avid Youtube watcher then you will have problems. If the block size is increased then the required bandwidth will also increase accordingly so uncapped, "always on" connections are a requisite.

Battery consumption is also a consideration but most people have been conditioned to accept poor battery life so it may be a non-issue. This could be alleviated to some extent by slight behavioural  changes to the mempool or smart burst management when not charging while fully engaging when charging. This aspect is not well understood at present since the community is dismissive of mobile platforms and I know of very little research in this direction. The worst case scenario is that you have to keep the mobile device plugged in permanently although I expect several hours of untethered operation is more than achievable with careful app management and changes to the core software.

So the hard limitation is the mobile bandwidth of the packages. If one has an uncapped, "always-on" mobile package then there is no reason a mobile platform cannot be used but some of the current operating aspects would need to change to make is usable by Joe Public.

How about the safety of Bitcoin in this case? I'm always thinking  about the safety.

I was talking to shinobimonkey about this, he's been doing it for 12 months now.

He uses Samsung edge 6. Initial synchronization took him about a week with him leaving it on charger as much as possible. He sync'd at around block height 450000 (so about January 2017), and both blocksonly and pruning are enabled. He says he used a version of bitcoin core 0.14 or thereabouts. The ABCore GUI has an option to only allow sync'ing when on wifi and charging.

I'm actually impressed how near-possible it is to be running a practical smartphone full node today.

Smartphone full nodes will be important going ahead because smartphone usage has already outpaced desktop for some use cases (e.g. web browsing) and is only going up from here.

What is the relation between Bitcoin core on a mobile device and a cold wallet?

Yes, of course, I think the Bitcoin Core software will continue in the future. It will not be too late to get started. It can be seen in a few years, but I think that Bitcoin's dominance is really big. This is really a great thing. Thereby, there will be a cool wallet on your smartphone.

 
It could work. The way I see it is :
 - create an Android VM that has enough size (GB) to synchronize and store all the blockchain
 - prune the blockchain to a size that your phone can handle
 - make a copy of the system and paste it onto your phone
 - have a wifi connection to sync your phone and have it plugged when syncing