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### Required number of bits in nonce [duplicate]

Is there a formal proof that with N bits to iterate in the nonce of the block, a hash satisfying proof of work will be ever found? How large that N (number of bits in the nonce) should be to satisfy ...
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### What if next block cannot be mined? [duplicate]

AFAIK to create the next block, there must be a specific structure (specific number of leading zeros) in the has output calculated on the block's header. This header contains a set of fixed parts (...
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### What is the expected time until the next block is found?

https://bitcoin.stackexchange.com/a/3908/659 says: Luckily, you'll only have to wait five minutes on average for a block to be found (blocks are one every ten minutes, so the expected delay until ...
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### What is the longest time gap between blocks in 2010 - 2011?

I notice on blockexplorer that block 159531 was mined at 2011-12-28 10:53:53 and the next block was mined at 2011-12-28 11:24:58 - a gap of more than half an hour. I know the 10-minutes-per-block rule ...
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### How is it that concurrent miners do not subvert each other's work?

Every time a new block is added on top of block chain, the miners have to restart their work because the next block has to have a proper reference to previous block. Let's suppose that there is some ...
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### Is it possible for the network to stop finding valid blocks?

The hashing problem is by design computationally hard, because SHA-256 hashes are for all intents and purposes random strings with no direct link to their inputs, and there's no (known) way to ...
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### Why does an adversary have to control 50% of the computing power to double spend?

If transactions in a block are valid, in order to add that block in the block chain, a proof of work needs to be found. I have read the bitcoin paper by Satoshi. If the difficulty of the proof of ...
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### how long does it take to get 6 confirmations with confidence of 99%

I had this question in an exam but I was not very sure how to solve it: Suppose Bob the merchant wants to have a policy that orders will ship within x minutes after receipt of payment. What value of ...
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### Has the nonce used in mining been sized?

In the mining process, everytime a block has to be confirmed, a certain hash with an incremental nonce is generated: If the nonce is a 32 bit number it can assume a value between 0 and 2^32 - 1. It ...
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### How does mining process takes Approximately 10 minutes?

I don't think that I fully understood the "difficulty" topic in blockchain, and therefore I don't understand how mining process takes close to 10 minutes. If I have "Target" value (some hash value, ...
263 views

### The probability that the entire network generates at least two blocks within 10 minutes?

We know that Bitcoin network on average generates one block per 10 minutes. Is there a formula to compute the probability that the entire network generates at least two blocks within 10 minutes by ...
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### More than one valid hash block

Discovering a new block is a task about generation of millions of hashes in order to find one valid hash, which is a hash less than the current target. The question is: Are there more than 1 valid ...
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### The probability of block generation by two miners in a special case?

If network would include 2 mining pools (pool_1 and pool_2) with the hashpower of 49% and 51%,respectively, then wo want to calculate the probability that in 10 minutes, exactly 2 blocks would be ...