Bitcoin Forum

There's already a good FAQ available from the bitcoin website: https://bitcoin.org/en/faq

@CoinLearn You may add the following Q

Q. What advantages a buyer get in using bitcoin ?

A. Following is a list of few advantages...

1. Buyer's card data is not coming to the seller. So no chance of theft from merchant's end.

2. Buyer's anonymity.

3. Recurring payment protection. Merchant cant enforce a recurring payment using a small checkbox tick.

Some kind of security lesson would be really good as well. The basics of cold wallets and encrypting your desktop wallet especially.  

@CoinLearn You may add the following Q

Q. What advantages a buyer get in using bitcoin ?

A. Following is a list of few advantages...

1. Buyer's card data is not coming to the seller. So no chance of theft from merchant's end.

2. Buyer's anonymity.

3. Recurring payment protection. Merchant cant enforce a recurring payment using a small checkbox tick.

Yah, I checked it and https://en.bitcoin.it/wiki/Faq is also a good one. But I dont want to copy-paste. Those can be presented in a less technical and interesting way for newbies. And I'm looking for some interesting Q/A as well. Here is an example...

Q. I heard someone bought 2 Piza for 10,000 BTC. Is it true ?

A. Yes, it absolutely is. The order was placed on May 18, 2010 and was executed on May 22, 2010. Those were the early days of bitcoin. You may find the details here (https://bitcointalk.org/index.php?topic=137.0).

Q. What is a 51% attack ?

FTFY

There is no such thing as anonymity in Bitcoin AFA.
Everything is recorded in a public ledger.

When I buy a domain in NameCheap using bitcoin, I remain anonymous. This is not the case for FIAT buying as they get my Credit Card info.

To the merchant yes. But your transaction can still be tracked.
That is what I was trying to say ;)

Transaction tracking is not a problem if the address owner is not known. This stands by the idea of staying anonymous using Bitcoin.

ALL address owners can be verified simply by following the transactions.
It might not be immediately but at some point it happens.

Why do you think the CIA loves the idea of BTC?

Because they can now track what they couldn't do before with plain old cash.

Whether you choose to deny this fact or not, it's there.

I am sure Gavin can verify that the CIA is just fine with the BTC protocol.
After all he explained it to them, and they had decided that it wasn't a thread (maybe even they had realized that it's their greatest ally).

 

Q. What is a 51% attack ?

I'm a big fan of this FAQ:

https://en.bitcoin.it/wiki/Myths

Yah, I checked it and https://en.bitcoin.it/wiki/Faq is also a good one. But I dont want to copy-paste. Those can be presented in a less technical and interesting way for newbies. And I'm looking for some interesting Q/A as well. Here is an example...

Q. I heard someone bought 2 Piza for 10,000 BTC. Is it true ?

A. Yes, it absolutely is. The order was placed on May 18, 2010 and was executed on May 22, 2010. Those were the early days of bitcoin. You may find the details here (https://bitcointalk.org/index.php?topic=137.0).

I'm a big fan of this FAQ:

https://en.bitcoin.it/wiki/Myths

CIA is not happy with the current protocol as they are unable to track anything. Hence they are trying push different changes in the protocol level through Gavin including 3rd party security certificate verification.

Is that your opinion or do you have any evidence?

The definitions of "online wallet" and "offline wallet" are confused. They mean different things to different people.

Generally, "offline wallet" means the same as "cold storage", or a wallet that is not connected to the internet. Some people use the term to mean a wallet that runs directly on a device -- phone, tablet, computer, etc.

Then you would expect that "online wallet" means a wallet that is connected to the internet -- the same as a "hot wallet", but that's not how most people use the term. Generally, when people refer to an "online wallet", they mean a wallet that is accessed through a web site, and sometimes more specifically an account at a web site that is not really a wallet. This may also be called "web wallet" or "hosted wallet".

I try to avoid using the terms "online" and "offline" because of the confusion.

Cold storage is the safest because someone needs physical access to the wallet to steal the bitcoins. Holding bitcoins in an account on a web site is generally unsafe. Bitcoins in accounts are easily and frequently stolen.

A bitcoin block hash is a sha256 (32 bytes). The hashed data contains several things, including the current time, the previous block hash and a random "nonce". Also there's a "target" (depending on the total bitcoin hashrate) value being calculated and which gives the number of zeroes your block must start with to be valid. If your block hash doesn't starts with enough zeroes, then you should try again with another nonce.

You might like to read the following to understand Bitcoin mining in simple terms...


What a miner is doing when it's running is generating millions of hashes every second. A hash looks something like 00000000000000000b8cd4a8a7752ff8785f66232359273f619f6a6cb28d4644. A hash is always 64 characters long. Each block has a 'target' hash, which looks similar to the string of characters above. When the hash that your miner generates has a lower value than the target hash, you win the block. An example with smaller numbers would be a target hash of 0017b5 (note that this isn't an actual hash for bitcoin as it isn't 64 characters long, this is just an example). If your miner generates the hash 0017a5, you win the block. However, if it generates the hash 0017c5, you don't win the block. The order of the 'value' of the characters from lowest to highest value are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f (which is actually hexadecimal no. system). As the difficulty increases, the 'value' of the target hash becomes lower, as more zeroes are added on to the beginning. This makes it harder for your miner's hash to have a lesser value than the target hash, so it gets harder to win the block. Notice how the example target hash above had 17 zeroes at the beginning, while the target hash of the first ever mined block (https://blockchain.info/block-index/14849) had only 10 zeroes at the beginning.

Mining difficulty is determined by the amount of time it takes to solve 2016 blocks. Every 2016 blocks, the nodes calculate how long it took since the previous adjustment.

If it took less than 20160 minutes, then the blocks are coming too fast (faster than an average of one every 10 minutes). The nodes then increase the difficulty by the same percentage as the excess speed. This increase in difficulty makes it so that if there is no additional hash power added to the network, the next 2016 blocks will take 20160 minutes.

If it took more than 20160 minutes, then the blocks aren't coming fast enough (slower than an average of one every 10 minutes).  The nodes then decrease the difficulty by the same percentage as the missing speed.  This decrease in difficulty makes it so that if there is no additional hash power added to the network, the next 2016 blocks will take 20160 minutes.

Since miners are always trying to increase their income, they keep adding hash power to the network.  This increase in hash power speeds up the blocks and causes the next adjustment to increase the difficulty.  Eventually it will reach a point where the miners are spending more on hash power than they are earning from mining.  At that point mining is no longer profitable for those who have the highest expenses per hash.  Many of them will shut down their equipment, which will reduce total hash power on the network and difficulty will drop.  This could happen in a few months, or it may not happen for a few decades.  Regardless, when it does happen, the difficulty will increase and decrease as miners add and remove hardware to try to maintain profitability.  Eventually an equilibrium will be reached, at which time difficulty will slowly increase in response to incremental advancements in technology leading to cheaper hashing.

The largest transaction size that will be relayed by a standard node is 100,000 bytes (https://github.com/bitcoin/bitcoin/blob/master/src/main.h). For it to be free as well, it would need (https://en.bitcoin.it/wiki/Transaction_fees#Technical_info) to destroy at least 400 Bitcoin days (e.g. spend 100 Bitcoins that were received 576 confirmations, about 4 days, ago).

A standard miner will only include up to 50,000 bytes of free/low-fee transactions, but the question was about relaying, not mining (besides, I expect most miners use non-standard implementations, and hopefully someone will include that in a block once it's relayed to them).