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?

Recover a bitcoin wallet in Hive

I’ve recently reformatted my Mac, and reinstalled Hive. I have a back up to Dropbox option enabled in Hive, and my old bitcoin wallet file is there. But I cannot find any way to recover my old bitcoin wallet to my new installation. Being able to back up but not recover doesn’t make much sense to me right now, can anyone help me with this process?

Coin address generation for all coins

We are developing UI for coin trading. We have a plan to use all the coins present in coinmarketcap. I am greatly confused how to generate coin address for all coins. I knew that from cryptsy.com, it is possible to generate address for all coins from bitcoin but I don’t know how to implement it. Is there any easiest way to generate coin address for all coins or can anybody tell how cryptsy do this for all coins? We are doing this in Ruby. Can you please suggest some more ideas to implement this. Any help is appreciated.

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?