I feel ashamed asking this but it's better to know than not knowing

[Crypt0Gore]

I have been around crypto for few years already and it's a shame that I still don't understand fully how crypto wallets work, I remember that in 2016 when I first installed my BTC wallet from the official Bitcoin website I use a lot of data to sync and download the blockchain data, now that we have mobile wallet for Bitcoin like Electrum how are they functioning? I install and start using wallet without downloading the blockchain data, I know it can't be cloud data, does this syncing has something to nodes?

[franky1]

mobile phone wallets connect to servers and the servers handles the blockdata. and you just get handed a small list of the unspent transaction outputs destined for your address(which servers know you have by your phones request)

where all your phones job is to use the unspent output as your fund origin and you decide who you want to spend it towards and sign it
your phone send the signed transaction to the server and the server relays it to the rest of the network

your phone (in electrums case) stores the secret key to do the signing of a transaction) where (in electrums case they dont store that secret)

some other phone apps can be even les secure where everything is server managed and the keys are on the server not your phone (Central exchange apps)

[NotATether]

It's not just mobile wallets, it's any wallet that uses SPV technology (simplified payment verification) that just connect to a network of full nodes that have been pieced together from the Bitcoin network, or other altcoin networks, and then sync the balances of their addresses by fetching transactions from the node, and manually adding and subtracting the transfer amounts without the node's help.

[hosseinimr93]

I remember that in 2016 when I first installed my BTC wallet from the official Bitcoin website I use a lot of data to sync and download the blockchain data

This may be off-topic, but it may worth mentioning that there is no official bitcoin website. Bitcoin isn't like a company which is owned by someone/group of people and has an official website. Bitcoin is decentralized and the users don't rely on a centralized service like a website.

[pooya87]

If you want to widen the description to more than just Electrum you have to realize that different "light" wallets have different implementations. Some of them are [single] server dependent and have to only connect to the centralized server that the company provides (meaning 0 privacy for users), Electrum is not like that since you can connect to any Full Node that has the implementation of Electrum protocol (basically indexed its blockchain to be searchable by address).

It is the same when it comes to the verification they do. Electrum downloads and verifies all block headers (each header is just 80 bytes) and it is capable of detecting chain splits and can verify things with multiple nodes. Other implementations sometimes don't have those options.

[BlackHatCoiner]

Think of it like this: There are two ways to know your balance.

• Request every block, verify every transaction that has ever happened, initially reaching the tip, and then figure out who owns what in terms of unspent outputs, including yours.
• Request this information to be delivered by another person, who's synced with the chain, and who has decided to freely share this info with anyone.

In the whitepaper the latter is described in the 5th page, and as said, is called "Simplified Payment Verification".

[ABCbits]

Take note most light/SPV wallet isn't designed with privacy in mind. If you wish to have better privacy without running any node/server, seek wallet which use BIP 157/Neutrino.

It is the same when it comes to the verification they do. Electrum downloads and verifies all block headers (each header is just 80 bytes) and it is capable of detecting chain splits and can verify things with multiple nodes. Other implementations sometimes don't have those options.

Take note few implementation such as Electrum heavily optimize block header size[1], while other implementation might implement it naively which require user to download >100MB worth of block header when they run wallet for first time.

[1] https://electrumx.readthedocs.io/en/latest/protocol-basics.html?highlight=80#block-headers

[pooya87]

Take note few implementation such as Electrum heavily optimize block header size[1], while other implementation might implement it naively which require user to download >100MB worth of block header when they run wallet for first time.

[1] https://electrumx.readthedocs.io/en/latest/protocol-basics.html?highlight=80#block-headers

That's an interesting piece of history that sounds more like an implementation fix or improvement rather than optimization since they had implemented it in a very terrible way at the beginning, downloading it as text and all that. You can literary connect to any full node on bitcoin network and send them a simple getheaders message with a "locator" to receive at least one header and either sync or verify your local headers file. Not to mention detecting chain-splits. All in bytes.
That is basically what the protocol is doing now. It uses hashes and the height alongside a hard coded deep header "checkpoint" to limit the verification.

[Crypt0Gore]

I remember that in 2016 when I first installed my BTC wallet from the official Bitcoin website I use a lot of data to sync and download the blockchain data

This may be off-topic, but it may worth mentioning that there is no official bitcoin website. Bitcoin isn't like a company which is owned by someone/group of people and has an official website. Bitcoin is decentralized and the users don't rely on a centralized service like a website.

I was not expecting this answer, if so, then I still have a question, like who owns or created Bitcoin.org? Because that was the first place I learn and read more about Bitcoin, so hossein sahab, what am I not getting here? I always thought that Bitcoin.org is the official website.

[hosseinimr93]

I was not expecting this answer, if so, then I still have a question, like who owns or created Bitcoin.org? Because that was the first place I learn and read more about Bitcoin, so hossein sahab, what am I not getting here? I always thought that Bitcoin.org is the official website.

Bitcoin.org was created by satoshi and is now control by Cøbra.
Take note that even if bitcoin.org was still owned by satoshi, we couldn't say it's the official website of bitcoin. Bitcoin has no owner and has no official website.


See what bitcoin.org says about the official website of bitcoin.

Bitcoin.org is not Bitcoin's official website. Just like nobody owns the email technology, nobody owns the Bitcoin network. As such, nobody can speak with authority in the name of Bitcoin.

[o_e_l_e_o]

A full blockchain node verifies a transaction by checking the entire chain of thousands of blocks behind it in order to guarantee that funds is not spent

Full nodes do not scan the entire blockchain for every transaction they receive - doing so would be computationally infeasible in a reasonable time frame and the whole network would grind to a halt. Rather, each node checks each new transaction it receives against its UTXO set. This allows the existence of pruned nodes, which download each block from the genesis block in order to verify them and build their UTXO set, but do not need to store them to be able to verify future transactions.

[Salahmu]

I remember that in 2016 when I first installed my BTC wallet from the official Bitcoin website I use a lot of data to sync and download the blockchain data

This may be off-topic, but it may worth mentioning that there is no official bitcoin website. Bitcoin isn't like a company which is owned by someone/group of people and has an official website. Bitcoin is decentralized and the users don't rely on a centralized service like a website.

hosseinimr93 could you please clarify me a bit on the aspect you mentioned that btc does not have an official website, could you believe I have actually been with the mindset that btc official website is Bitcoin.Org, so is I may ask since btc does not have an official website what then is Bitcoin.org? I need some clarification about it, because I don't know much and will be very happy to learn.

I have a friends that ask me bout btc official website and I always referred them to Bitcoin.org with the believe that is the official website.

[Lucius]

~snip~
I have a friends that ask me bout btc official website and I always referred them to Bitcoin.org with the believe that is the official website.

Tell your friends that Bitcoin is a decentralized cryptocurrency, so as such it cannot have any official websites, banks, or people who represent it - anyone who doesn't want to or can't understand it always has the alternative of looking for a centralized project that has all those things projects usually have. I doubt that @hosseinimr93 can explain more what he wrote, because the explanation is more than clear.

[o_e_l_e_o]

The "About Us" page on bitcoin.org explains it in great detail: https://bitcoin.org/en/about-us

Bitcoin.org is not Bitcoin's official website. Just like nobody owns the email technology, nobody owns the Bitcoin network. As such, nobody can speak with authority in the name of Bitcoin.

The website is developed and maintained by a group of volunteers via GitHub: https://github.com/bitcoin-dot-org/Bitcoin.org

[StarBets]

This may be off-topic, but it may be worth mentioning that there is no official Bitcoin website. Bitcoin isn't like a company that is owned by someone/a group of people and has an official website. Bitcoin is decentralized and the users don't rely on a centralized service like a website.

Bitcoin.org was developed by Satoshi and Martti Malmi aka Sirius. Even though that is unofficial, people consider it official. The funniest thing is, People, Consider Bitcoin.com is an official website and wallet service that even allows its users to buy altcoins.

Even BitcoinTalk Rules titles say "Unofficial list of (official) Bitcointalk.org rules, guidelines, FAQ". That doesn't mean it's not official and users won't follow them. So, no matter what you say about Bitcoin.org, it was registered by Satoshi and Sirius and this is enough.

Nora,
StarBets

[robelneo]

Bitcoin.org was developed by Satoshi and Martti Malmi aka Sirius. Even though that is unofficial, people consider it official. The funniest thing is, People, Consider Bitcoin.com is an official website and wallet service that even allows its users to buy altcoins.

People are used to attaching anything to a company or centralized organization, I remember when I invited a friend who is active in MLM he is ask me about the company's physical address, and when I told him that there is none, he easily conclude that its a scam because there is no organization that manages it.

When you're introduced to Bitcoin a whole new world opened up to you, if you have no idea about decentralization you have to empty your mind and be open-minded because Bitcoin is a new concept for newbies, who are used to centralization all their lives.

[hZti]

People are used to attaching anything to a company or centralized organization, I remember when I invited a friend who is active in MLM he is ask me about the company's physical address, and when I told him that there is none, he easily conclude that its a scam because there is no organization that manages it.

This is only because in the bitcoin world, there are a lot of smart people that check if all the open source projects are legit. If you are a average user it is always wise to act like your friend and question stuff like this. Because as one single person you can never check if all the stuff that you are dealing with on daily basis is legit.
This is the beauty of the internet community, where so many people can come together and help each other.

[DannyHamilton]

Bitcoin.org was developed by Satoshi and Martti Malmi aka Sirius. Even though that is unofficial, people consider it official.

That is a mistake.

People who understand and know what they are talking about do NOT "consider it official".

People who are new and haven't learned yet, and people who are misled, and people who have made some mistaken assumptions might consider it official, but that is why the website itself says that it is not the official website and why it is important for those who do understand explain it to the rest.

There is no official "Bitcoin" website or "Bitcoin" organization in the same way that:

• There is no official "water" website, responsible for all the world's information about water
• There is no official "carbon" website, responsible for all the world's carbon
• There is no official "magnetism" website, responsible for all the world's magnetism
• There is no official "oxidation" website, responsible for all the world's oxidation
• etc

These things (water, carbon, magnetism, oxidation, bitcoin, etc) all exist, and there are websites that share information about all of them. Some of that information is very detailed and may be associated with organizations that have a lot of control over that thing in a particular geographic or political area.  However, none of those organizations are the universal "official" organization, nor are any of the websites the single official website of that thing.

[Zoomic]

Bitcoin.org was developed by Satoshi and Martti Malmi aka Sirius. Even though that is unofficial, people consider it official.

That is a mistake.

People who understand and know what they are talking about do NOT "consider it official".

Great explanation!
In simple terms, if you say there is an official bitcoin website (bitcoin.org),  you are indirectly centralising bitcoin. Think about it.

EG. If information of hardforking is published there, there won't be any reason for consensus since it's the official website, the information should be treated as undisputed