Try the following:

1. Go to the iPhone Settings App (your phone settings)
2. Select General
3. Select Date & Time
4. Enable Set Automatically
(5. If its already enabled, disable it, wait a few seconds and re enable it)

You can check the settings.

But you can also find out which method you are using by looking at the code which gets generated.

Does a new code get generated each time you click a button? -> Counter-based -> HOTP.
OR does a new code generated after time has elapsed (e.g. every 30 seconds) -> Time based -> TOTP.

Invalid (TOTP-)codes are mostly to non-synchronous time between your mobile and the google server. Binance itself works fine for me.

This is a bad mistake.

Technical analysis do not work in a market without any regulation or logic.
Currently, BTC is a purely speculative market. People are trying to find a price which represents bitcoins value.

Additionally whales do manipulate the market to make personal gains. TA's are probably the least you can trust in the crypto world.

If you just started to learn about consensus algorithms and decentralized projects itself, chances are high your project will contain massive bugs and will be worthless.
If you are really serious about developing a proper project, get a team of a few developer to build proper software.




You can take a look at the github repository of ethereum. Proof of stake is pretty detailed explained in the FAQ: https://github.com/ethereum/wiki/wiki/Proof-of-Stake-FAQs

Do you use google authenticator?
If so, are you using TOTP method (time-based code) or HOTP (counter-based code) ?

If you are using TOTP (the most frequently used): Check that the clock of your phone is synced.
You might try to sync it mannually in the settings. This is one of the most frequently appearing 'problems'.

With PoS you are probably refering to Proof of Stake ?

In PoW miner try to generate a valid block (whose hash is below a specific value (determined by the difficulty)).
The first to generate a valid block can publish it.

In PoS the stake does determine who will be chosen to append the next block to the blockchain.




You shouldn't start a project on your own if you don't actually know how everything works in detail.
If you are serious about creating a new (non shit-)project, hire a competent developer team.

Bitcoin exchanges are working in an unregulated space. Whales with massive amounts of money are taking profit where they can.
So while it indeed makes sense that the price has been manipulated up to 20k $, it also has been manipulated down to 6k $.

And this manpulation game did not stop yet. And it probably will take quite some time until the manipulation has been decreased to an 'acceptable' level.

Currently the two best options are to either (1) hold long-term and don't care about short-term swings or (2) play the game and try to get the most out of it.

No.

You won't find fast and easy money anywhere.

But if you are convinced that the current financial system is doomed to fail and are looking for a better alternative, and you are ready to wait several years or even decades, then yes.. it can be very profitable to exchange fiat to crypto.
You might come across several projects / people who promise to deliver guaranteed profits. Or others who try to convince to buy into the 'next bitcoin'. Those are all scam.

If you are in for fast and easy money, you might try to buy a shitcoin and hope for it to pump high enough for you to cash out. But you might aswell take that money and go gambling in las vegas.

If you do believe crypto is going to change the world, buy some and forget about them. If you don't invest more than you can afford to lose, you won't have any sleepless nights.
In 10 years you will either (1) have lost money you were ready to lose or (2) have made a huge amount of money granting you a better lifestyle.

Calling bitcoin electronic money is the same as calling amazon a website. While it is not wrong, it is by far not the best description.

Electronic money is already everywhere. Just a fraction is being paid cash. Salarys, taxes, rent, ... are mostly paid electronically.

Being digital is not the fact which leads to increased demand of bitcoin. It is the trustless decentralized nature without any authority being able to create/steal/control the money.
Dollar bills and credit cards do both represent the same currency, with one being digital.

You seem to missunderstand the question from OP.
He asked how one can secure a new coin from 51% attacks. Not how user can secure themselfes from a double spend.

Additionally with 51% hashrate (assuming OP talks about PoW coins) one can generate blocks faster. Therefore a victim would not see there is an attack ongoing, once the reorganization happens (after X blocks).
Noone can notice anything 'fishy' until it happened.

Nothing is impossible.

Just because they don't have an API for trading, this doesn't mean you can't automate the whole trading process and create a bot.
The easiest implementation would be to display the website and simply click/enter the correct numbers in the correct fields (specified with ID's).
Thats more than just a few lines of code (like in simple API trading bots), but it isn't too complex to be built within a reasonable timeframe.

You can move/copy it to any directory you want.
If you are moving the data directory you will have to specify this new directory with a startup command: -datadir="C:\your\path"

Note that in case you want to store the whole blockchain on an external hard drive (which i am assuming because you are asking for the size of the drive), it may be more error-prone to file corruption.
Core needs a continious connection to your hard drive which is easier to achieve with an internal than an external drive.

Anyway.. as LoyceV aready mentioned, 1 TB is definitely enough to store the blockchain until way better drives will be available at half of the current price.

No, they do not get forwarded. Your wallet does hold multiple private keys.
When you are going to spend some BTC, your wallet will make a transaction with all coins you have received, combining multiple inputs (from addresses).

You don't have to change any settings. Look at an address like an invoice number. Give a new address out everytime you want to receive something.
You can always receive to the same address. And if you going to send coins, your transaction will simply say 'take input X and Y and Z ...'.

I understand that. But after the block got orphaned, the node definitely knows that it is not part of the longest chain and (theoretically) can be discarded.




I was not refering to blocks which are included in the longest chain. I was refering to orphaned blocks.
In your statement you were talking about reorganization of the latest X blocks.

Nodes do not need to store blocks which are currently not in the longest PoW chain.
If my node is up to sync and someone else broadcasts a new block whose heigt is 1 above the 'current' height, with different 'previous' blocks, i do not need to have those previous blocks (which weren't part of the blockchain until this newest block got broadcasted. I could easily just request the block information from this node (who definitely has the information since a miner built upon it). 




If you, with 'nodes blockchain' refer to the block files (blk*.dat), then this answers my question. Thanks.

Each node can decide for his own whether a block is need (e.g. part of longest chain) or valid (has to be validated anyways).




Theoretically it still would not be necessary to store this block. In case of a reorganisation the block(s) can easily be broadcasted / received via the network.
Since nodes do choose the longest chain, why do they need to store an orphaned block from years ago ?

Do most clients (bitcoin core?) really store those orphaned blocks (especially from years ago)? If so, is there a specific reason why it has been decided to keep them ? Or are they just kept because there is no real reason to delete them?

Is there a practical reason for orphaned blocks being stored ? Once a block turns out to be orphaned the valid transactions get added to the mempool again.
But what is the actual reason to further store this block if the information it cointains is no longer needed?

Unfortunately, short googling didn't bring a reasonable answer.

Does the first error still appear? Because if all updates went successful, it should disappear.
Do you have a cracked windows copy (not that i am expecting an answer now, but this causes such issues) ? Your settings might be somehow corrupted/modified.
Did you check the update logs whether all updates went successfully ? Windows does show no new updates even tho the last one failed sometimes. The update history should reveal any failed updates.

Regarding the second error, do you have python installed? If not: https://www.python.org/downloads/release/python-365/

They aren't.
They did update the app a few days ago. And a few weeks / a month ago they have released the first 'module' (unfortunately the bcash module).
But i am pretty sure they said segwit is the next 'big' update to come.

I am still using mycelium as my only btc mobile wallet. Didn't have any problems with it yet.

No, you misunderstood this.

A private key is a 256 bit random number. And the hash function SHA-256 does produce a 'random-looking' output (depending on the input).
So quite a few people came to the idea to hash a 'password' to generate a 'random looking' number.

5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8 <-- This may look random. But it is the output of sha256('password').

So people started using passwords to generate private keys (thefore 'brain wallet').
Then smarter people started to program bots who create hashes of the most common passwords, most common prases, books, etc... to collect all the money stored in such 'brain wallets'.


While you think you may be able to find a 'random' input, it will always be less random than using a machines entropy pool. A human brain is very very far away from 'random'.

Now wallets nowadays do use entropy to achieve randomness. A random seed is generated, which is then being encoded into 12/24 words (this makes it easier for user to backup / memorize the seed and it is less error-prone when typing).
Those are NOT brain wallets. And NEITHER can they be bruteforced or hacked.
It is just a differend form of representing the random seed which is used to derive all of the public-/private- keypairs.

Don't worry.

Most wallets do generate a new address for each receiving transaction. This is done due to privacy reasons.
You were given a seed to backup (12/18/24 words). With this words ALL of your addresses can be regenerated. Imagine it like a function: newAddress = getNewAddress(seed, counter) (in reality its a bit more complicated, but that shortlly represents it).
You will also always be able to receive more funds to this address. And your wallet will generate a new address every time you receive coins to your 'latest' receiving-address.