What happens if I delete wallet.dat?

I have this question, say I have my coins in my local wallet and 1 of 2 things can happen, say I somehow delete the wallet.dat file or some kind of malware deletes the file. I have the password private key to the wallet, would I need the wallet.dat file to recover the bitcoins or could I just recover with the private key to the address? Would I need both?

Can someone explain nLockTime?

I’m having a hard time understanding how nLockTime works. The Bitcoin wiki has an explanation that is confusing to me:

nLockTime is a parameter that can be attached to a transaction, that mandates a minimal time (specified in either unix time or block height), that before this time, the transaction cannot be accepted into a block.

Can someone explain it in plain English, with an example?

Trying to calculate the strength of a brainwallet created with a custom diceware

I want to create a brainwallet using a custom diceware since I don’t like the original one. Instead of 7776 words it has 46656 because I use 6 dice for each word instead of 5.

So this is what I got so far, please tell me if I made a mistake:

2 ^ (log2(46656) * 5) / (1 * 10^15) / (60 * 60 * 24 * 365) = 7 years

  • 2 ^ (log2(46656) * 5) is the entropy for a brainwallet of 5 words
  • 1 * 10^15 is 1 Phash/s, which is the hashing power I’m assuming for this attacker. I don’t even know if this makes sense, because an attacker doesn’t need to start over for each brainwallet he wants to crack.
  • 60 * 60 * 24 * 365 represents a year in seconds

Why is it so difficult to track & recover stolen Bitcoins?

I have to admit I don’t fully understand the Bitcoin protocol. But from what I do understand, transactions are traceable — it is the main reason decentralization works: the world can watch and confirm that a transaction is legit.

Why then can’t we observe when a thief tries to cash out or otherwise exchange a Bitcoin that we know to have been stolen?

As Robert Wagner writes:

1 out of every 14 Bitcoins is now stolen property, and there are
plenty of laws governing stolen property.

What am I missing here? With so many Bitcoins identified as “stolen,” why can’t they be traced, recovered and returned to their rightful owner?

How do I cancel my blockchain transaction (still unconfirmed)?

I am using blockchain.info.

I have made a bitcoin transaction of 22.00883562 BTC to the address 1A9eUAc78tGx65X3CuC9WfSKXXgxjU8ccC.

You can see the transaction at https://blockchain.info/tx/97c1af82111cdcf17f878eb6df20c17c59c1b1fc04e8cdce36b8ac6c6d1c969a

I have paid a 0.001 fee but it has been almost 30 hours and it still shows “Unconfirmed”.

What could be the error? Also, more importantly, how do I cancel the unconfirmed transaction and get back my coins?

How to create a bootstrap.dat file? [duplicate]

I want to create a new bootstrap.dat file for a Dogecoin. How do this kind of files are created and how can I create one? What tools should I use? any answers/links/references are appreciated. I have searched here, but I haven’t found any satisfying answer. I saw this post: Creating my own bootstrap.dat but there is no method mentioned of putting the block in the bootstrap.dat file. Saw this post too: How do you generate a bootstrap.dat file? but the tools mentioned are for Bitcoin and I’m not sure how to use them…. can anyone create a more explicit, step-by-step tutorial for doing this? something that anyone can understand? thanks in advance!

Is there a point where bitcoin mining will not be profitable?

A lot of news accounts are pointing out that bitcoin mining is getting more difficult over time, murch even said recently in chat its getting “exponentially harder”. I am not sure if that is the case, but has anyone studied the economics and difficulty/hardness of bitcoin mining over spans of time? it appears clearly & by design to be subject to “diminishing marginal returns”.

Is there a forecast when bitcoin mining will reach “break-even” level & be exactly as expensive as the hardware/energy required to mine it?

I am looking for quantitative/scientific analysis where possible. By the way, its a completely separate question of whether this would mean that bitcoin is no longer usable as a currency. (To me that is very likely not the case.)

Full example data for scrypt Stratum-client

I’m trying to write a Mining client for Scrypt-based mining using Stratum Communication.
As of now, I have some trouble verifying all my bit orders and sequences. Hashes I’m generating get always rejected due to not meeting the Target.

What I’m looking for is a full sequence of data, starting from the information I get from the stratum server (coinbases, merkles,…) to a final hash.

I could already verify parts of the algorithm (mainly from input to a valid merkle-root, using the information of http://mining.bitcoin.cz/stratum-mining/ , and a scrypt hashing, using the block header from https://litecoin.info/Scrypt ), but I guess there is some endian problem in between, or something completely different, I don’t know… With a full workflow I could verify where the error happens.

Does anyone know where to get such data, or how to generate them for myself?