[for merits] Discuss the implementation of lightweight nodes for mobiles.

[Jet Cash]

We are starting to see reports that mobile users may be able to run lightweight nodes on mobile devices. Discuss this possibility, and the advantages and disadvantages if they do become generally available.

[Jet Cash]

>..<

You should know by now that I'm looking for original posts, and considered opinions.

I very nearly put you on ignore for just copying that article without any constructive comment.

[madnessteat]

Sorry. I'm confused. I wanted to edit the post and accidentally deleted it.
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Edit: I think the use of lightweight nodes for mobile phones is not quite safe today, but it is quite convenient.

[Jet Cash]

Why would I want any merits - I'm a merit source?

I'm trying to stimulate some sensible discussions on this board, instead of the TwitBook and ICO threads that shouldn't be here, and that stop the better members from receiving merits.

[bitmover]

As far as I understand, Lightweight node are like SPV wallets, which include all mobile wallets.

They are very important for adoption.

If you want to buy a coffee, you don't to run  a full node on your phone.
Just use some wallet like coinomi/samourai/mycellium etc, scan the QRCode and it´s done. Even 1 confirmation is OK.

Running a full node is important for people who own business and want to validade all transactions by themselves, without relying on third party to know if he has received is money or not.

These kind of services were even described in bitcoin whitepaper, at Chapter 8 -  Simplified Payment Verification (SPV)

8. Simplified Payment Verification
It is possible to verify payments without running a full network node.  A user only needs to keep
a copy of the block headers of the longest proof-of-work chain, which he can get by querying
network   nodes   until   he's   convinced   he   has   the   longest   chain,   and   obtain   the   Merkle   branch
linking   the   transaction   to   the   block   it's   timestamped   in.     He   can't   check   the   transaction   for
himself, but by linking it to a place in the chain, he can see that a network node has accepted it,
and blocks added after it further confirm the network has accepted.

As such, the verification is reliable as long as honest nodes control the network, but is more
vulnerable   if   the   network   is   overpowered   by   an   attacker.     While   network   nodes   can   verify
transactions   for   themselves,   the   simplified   method   can   be   fooled   by   an   attacker's   fabricated
transactions for as long as the attacker can continue to overpower the network.   One strategy to
protect against this would be to accept alerts from network nodes when they detect an invalid
block,   prompting   the   user's   software   to   download   the   full   block   and   alerted   transactions   to
confirm the inconsistency.  Businesses that receive frequent payments will probably still want to
run their own nodes for more independent security and quicker verification

Personally, i have a mobile wallet with few money in it. Like the same amount of money I would hold in my physical wallet.

if you are going to travel abroad, it may be handy to have a mobile with some money, as you can always find some place that accepts bitcoin and use it.

[nkampala]

Since lightweight nodes are able to confirm transactions, mobile users could essentially use a lightweight node in a similar fashion to a mobile banking app. They could be able to view their balance without having to run a full node (which would be a huge, battery draining task for a mobile phone), and it could provide functionality for real-time notifications of incoming transactions and when an outgoing transaction is confirmed.

If something like this became generally available, it could greatly facilitate bitcoin becoming more widely accepted in retail and peer to peer situations, and especially in countries where mobile phones are more widely used than a desktop computer or laptop.

Some of the disadvantages would be that lightweight nodes open up more privacy and security concerns than running a full node. Since lightweight nodes have to rely on third-party providers with a full node to deal with sending transaction, which introduces another opening toward potentially getting hacked. Also, if for whatever reason there's an attack on the bitcoin network itself, and invalid transactions are confirmed, the lightweight nodes won't be able to tell the difference, which would affect a ton of people, businesses, and probably the whole bitcoin economy.

Obviously, for the lightweight nodes to be widely available and still work as intended, there needs to be a strong network of full nodes behind it to be able to keep everything in check. I think if this becomes the new norm, it would be great if retailers would set up their own full nodes to actually verify payments, giving both a trusted node for customers to connect to, and adding to the security of the network as a whole.

[Discoperi]

What if the light nodes were downloading not headers of all blocks, but only the last blocks instead and flushed them after synchronization (and getting more recent blocks to store)?

Or would that produce side chains?