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2
votes
2answers
59 views

Are Bitcoin Block Hashes Predictable

to create the block chain, the Bitcoin network runs hashing algorithms for each block, is it mathematically possible to predict the hash value of say, the 100th block from the last block currently in ...
1
vote
1answer
42 views

Why does the hash come before the signature?

The first figure in the original paper of Satoshi is a diagram of transactions. This diagram seems to indicate that the transaction data is hashed before the sender's signature is appended. Why not ...
4
votes
2answers
124 views

What is the variable in a block that holds hash of found PoW?

Can anyone please tell me, which variable holds the hash of the solution of block's PoW in broadcasted block? I know that a block consists of (I am pretty sure I am forgetting some variables here): ...
-1
votes
1answer
35 views

Using blockchain to publish downloadable software verification codes

What is the point of comparing sha256 of downloaded file with published on the same website code? Why can't developers of currencies publish file version and sha256 hash on blockchain as alias or ...
0
votes
0answers
30 views

How does Multi-Signature Pay 2 Script Hash (P2SH) enable stronger security?

Coinfloor says it will pay out withdrawals using Multi-Signature Pay 2 Script Hash. What is Multi-Signature Pay 2 Script Hash? I read What is "Script Hash" address exactly and how does it ...
0
votes
0answers
44 views

Is there a way to brute-force crack a multibit password?

I am trying to use John the Ripper but everytime I use the bitcoin2john.py wallet01.wallet > wallet01.hash it asks for data directory. Anyone successfully crack a multibit password?
2
votes
2answers
144 views

What does the mining difficulty number really mean?

I'm new to bitcoin; please bear with me. I'm looking into mining, how it works, and how to get started. I see a "mining difficulty" from many sources and list a 3 billion something number without ...
6
votes
2answers
132 views

How come you know that a proof will be found so that the hash function will produce 000…xxx…?

How do we know the HASH function will produce an output 0000...xxxx...xxx. Is it possbile that no proof will be found so that the HASH will produce that output 000...xxx...?
0
votes
0answers
52 views

Miner and Pool Discrepancy

I'm new to mining and trying to understand some discrepancies that I am seeing. my CPU hash rate is showing greater than 6000kh/s but the pool is only reflecting 30Kh/s. Is there a difference ...
-2
votes
1answer
2k views

What is the conversion then for MH/s to GH/s and so on [duplicate]

I've seen this answer and maybe I'm just tired What is the difference between KH/s MH/s GH/s? 1 kH/s is 1,000 hashes per second (sometimes mistakenly written KH/s). 1 MH/s is 1,000,000 ...
1
vote
1answer
81 views

Why is a double hash of the previous transaction included in Txin?

In Txin, there is a double hash of the previous transaction. Why? What purpose does that serve? How is this data used later?
1
vote
1answer
100 views

How is the solution hash in a block generated?

For example, in the Genesis block in Bitcoin, from which values was the solution hash "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f" derived from? I understand that the nonce is ...
0
votes
1answer
56 views

Is there any way to directly query the block chain for the body of a transaction given its hash?

Blockchain.info provides this functionality in a simple API like so: https://blockchain.info/rawtx/fc15f762e8dbbdd407534047ef2a9211ca0e79c3625d5fe73cdacade4f9118d6 However, I would prefer to make ...
0
votes
1answer
7k views

How to work out my hardware's hashrate power

Using my existing hardware, I want to work out which altcoin is still profitable to mine. I have found this link: http://dustcoin.com/mining But don't know which values to enter into the boxes at ...
0
votes
0answers
767 views

What affects hash rate/share rate relationship?

I've read some answers to questions relating hash rate and share rate, and have come under the belief that they ought to be directly proportional i.e. a 2x hash rate should lead to 2x share rate as ...
1
vote
2answers
79 views

Could there be an exploit by creating millions of meaningless transactions? [duplicate]

Would it be possible to hamper the network's efforts in validating blocks by creating millions and millions of bogus transactions- simply sending back and forth say 0.1 BTC from address A --> B --> C ...
5
votes
7answers
434 views

What is a good analogy (which a layperson would understand) for the process of Bitcoin mining?

I will be explaining Bitcoin to a non-technical group and I am hoping somebody can provide me with a very basic visual analogy of the crypto-currency mining process. My half-baked idea, was to ...
1
vote
3answers
1k views

How to calculate Hashes per Second

How exactly do you calculate how many hashes your hardware is generating?
2
votes
2answers
102 views

Are any hashes (Tx or block) actually stored in the blockchain?

...or is each client responsible for storing hashes for blocks and transactions in their own database? So when I send a transaction, I indicate the prev_out by its hash, and I just assume everyone on ...
-1
votes
1answer
1k views

Not getting enough Hashrate

I have an i3-3220 processor which i am using for mining. I know that you're supposed to use a GPU and all that. But currently i'm just trying it out before spending money. I'm using CPUMiner, mining ...
2
votes
2answers
736 views

Shares accepted vs hash rates?

I recently started mining LTCs, and because Im using a Nvidia card (GTX 650Ti) I have been trying out different settings in order to maximize efficiency with the hash rates. I have noticed though ...
1
vote
1answer
166 views

Math and Bitcoins

I'm doing my IB math SL internal assessment on bitcoins. We have to incorporate a lot of math into a 6-12 page essay on our topic. What could I talk about for bitcoins that relates to ...
1
vote
1answer
3k views

What is a “share rate”?

What is a "share rate" one can find in a mining pool dashboard? I understand what a hash-rate is, and how that applies to myself (miner), as well as to the pool or the network. I also understand to ...
0
votes
1answer
186 views

In Ripple, what exactly is “Hash256”?

In various places on Ripple Wiki we can see the type Hash256 (for example here). What data structure is it exactly? Is it just a 256 byte array, or are there some rules governing this type (and ...
-1
votes
1answer
89 views

understanding timestamp from blockexplorer.com

What is the timestamp used for the blocks on blockexplorer.com For example block 233969 has: Time: 2013-04-30 23:27:36 is this time converted to 32bit hex for hash calculation, if so how ?
0
votes
2answers
70 views

Construction of unowallet url

I just tried to use unowallet. It seem that the private key is somehow encoded into the url. Isn't it some known type of representation? Wouldn't it be possible to create an url for my private key? ...
2
votes
3answers
9k views

How many hashes create one Bitcoin?

No matter how long it takes to calculate one hash, but how many hashes are required to get one Bitcoin?
5
votes
2answers
3k views

How is the network hash rate calculated?

Miners work on finding blocks but don't sent anything until they find the block. Considering that, how can sites like bitcoincharts.com display a graph of the network hash rate?
4
votes
1answer
1k views

What is the hash-rate of the Bitcoin network that results in the maximum difficulty?

According to https://en.bitcoin.it/wiki/Target the target is a 256-bit number. As the total hash-rate of the Bitcoin network rises, this number decreases to increase the difficulty. How much hash-rate ...
5
votes
1answer
383 views

bitcoins can use different algorithm, how and implications

I read that if sha-256 was compromised at some point in the future, or for any other reason, bitcoin could switch to a different algorithm can someone detail how exactly that would work, and what the ...
7
votes
1answer
182 views

When a transaction is broadcast to the network, what is actually being sent?

When a transaction is broadcasted to the network, what is being sent? Is it a hash? if yes, is it going to be the hash of: previous transaction + public key of the receiver?
3
votes
1answer
2k views

What is “Script Hash” address exactly and how does it work?

I found out this address playing with blockchain https://blockchain.info/address/3NukJ6fYZJ5Kk8bPjycAnruZkE5Q7UW7i8 I found out it's something called "scripthash". How does it work exactly? How does ...
6
votes
2answers
1k views

Why does Bitcoin use two hash functions (SHA-256 and RIPEMD-160) to create an address?

Why do we use 2 hash functions (both SHA and RIPEMD) to create an address? Why not just use one hash function?
1
vote
1answer
181 views

How to use block and transaction hashes for generating simple stochastic chances?

Many online Bitcoin gambling websites use the block chain info to prove fairness. Most of them use rather complex algorithms for this with pre-published secrets. What most of them basically achieve: ...
4
votes
2answers
201 views

Possible to create a double spend attack by replacing a Tx in the merkle tree?

This question on crypto.SE describes how preimage attacks are avoided in the Bitcoin network. For a second preimage attack: hash(x) = hash(y) implies hash(hash(x)) = hash(hash(y)) So it ...
6
votes
2answers
401 views

Why are hashes in the bitcoin protocol typically computed twice (double computed)?

According to the wiki specification of the bitcoin protocol, hashes are typically "computed twice". For example: hello 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 (first round of ...
3
votes
1answer
225 views

What would happen if two public keys had the same Base58 hash?

If two different public keys had the same Base 58 hash, what would happen? Could one key spend money in the other account? What would happen to the monies received by the shared base58 hash?
6
votes
1answer
3k views

Relationship between Hash-Rate and Difficulty

What is the algebraic relationship between Total Network Hash-Rate and Difficulty?
-1
votes
1answer
518 views

What computations does Btcoin perform during mining? [duplicate]

Possible Duplicate: What exactly is Mining? What are the exact computations dies Bitcoin is performing during the mining? I understood that it has to do something with hashes and ...
3
votes
3answers
486 views

how can I insert an arbitrary sha256 hash into the blockchain?

If I want to prove that I wrote a particular document before a certain point in time, it would be sufficient to generate the sha256 hash of the document and somehow arrange for that hash to appear in ...
8
votes
6answers
1k views

Can more than 1 block be solved per 10 mins on average (LONG TERM)?

I am wondering whether it is possible for a supercomputer to find the next 1000 blocks in a very short amount of time. Hypothetically, if a government agency concentrated a supercomputer on hashing, ...
2
votes
3answers
503 views

Where can I see an input that will hash to a solution?

So as my understanding goes, there's some input (block header) that needs to be altered (via a nonce or other mechanism) which is run through a SHA256 to generate an output with X amount of leading ...