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Still I can't understand how to mine Nxt!!?
There is no mining but rather generating of new blocks (you get all transaction fees of the transactions in it).As I understand to generate new block you need that pseudorandom number (based on your address key and block that you are trying to extend) be less then target number which linearly depends on total number of NXT in you address.
Can somebody knowing how NXT works reply to this?
https://bitcointalk.org/index.php?topic=360692.0
https://bitcointalk.org/index.php?topic=360692.0
Hello guys,
Despite the lack of the white paper let's discuss the possible weaknesses of this coin.
Probably here is potential vulnerability:
In PoW currency you can remine a block to build a longer chain. In Nxt the order of generating accounts is determined, you can't create a long chain that contains blocks generated solely by you. With 51% of the stake the odds to generate a longer chain with 10 blocks are less than 0.1%. If someone buys a car with NXT they can wait a little bit longer to counteract even 90% attack.
I like that you plan to make things deterministic. My ideas for pure PoS have also been deterministic.
There is a potential problem here though.
How do you deal with AWOL coin-owners? If I can't make a winning chain with 51%, then can the chain continue at all if 49% of coins are lost?
Looking forward to the details so I can see how you address this and other issues.
It's a good chance to tell the details...
Each block has "generationSignature" parameter. An active account signs "generationSignature" of the previous block with its private key. This gives 64 bytes which are hashed with SHA256. The first 8 bytes of the hash gives a number (I call it a "hit"). The hit is compared to the current "target" (64bit number). If the hit is lower than the target then next block can be generated.
The target for each account is proportional to the balance. Someone holding 1000 coins gets a 50 times bigger target than someone with 20 coins. Thus the owner of 1000 coins will generate 50 times more blocks than the owner of 20 coins (in the long run).
The target is not constant, it grows each second passed since the timestamp of the previous block. If noone generated a block on the first second then the target becomes 2 times bigger and so on. The base target is the target on the 60 second mark. If there is only a few active accounts then after a long time someone will generate a block because the target will become very big. If you open the client and log with any funded account you can see a ticking timer in BLOCKS widget. It shows when the target will become greater than your hit.
So, what does it mean?
If I have two addresses with A and B coins and the maximum possible hit value is N (2^64) then probability that I will generate new block is
1 - (1-A/N)(1-B/N)=(A+B)/N - AB/N^2. But if I join these two addresses the probability of generating new block becomes (A+B)/N.
It gives serious incentive of joining your NXT with somebody else NXT (since you and other one will gain strictly more than separately). Apparently this implies of appearing one megapool that will control much more then 50% of all NXT.
Despite the lack of the white paper let's discuss the possible weaknesses of this coin.
Probably here is potential vulnerability:
In PoW currency you can remine a block to build a longer chain. In Nxt the order of generating accounts is determined, you can't create a long chain that contains blocks generated solely by you. With 51% of the stake the odds to generate a longer chain with 10 blocks are less than 0.1%. If someone buys a car with NXT they can wait a little bit longer to counteract even 90% attack.
I like that you plan to make things deterministic. My ideas for pure PoS have also been deterministic.
There is a potential problem here though.
How do you deal with AWOL coin-owners? If I can't make a winning chain with 51%, then can the chain continue at all if 49% of coins are lost?
Looking forward to the details so I can see how you address this and other issues.
It's a good chance to tell the details...
Each block has "generationSignature" parameter. An active account signs "generationSignature" of the previous block with its private key. This gives 64 bytes which are hashed with SHA256. The first 8 bytes of the hash gives a number (I call it a "hit"). The hit is compared to the current "target" (64bit number). If the hit is lower than the target then next block can be generated.
The target for each account is proportional to the balance. Someone holding 1000 coins gets a 50 times bigger target than someone with 20 coins. Thus the owner of 1000 coins will generate 50 times more blocks than the owner of 20 coins (in the long run).
The target is not constant, it grows each second passed since the timestamp of the previous block. If noone generated a block on the first second then the target becomes 2 times bigger and so on. The base target is the target on the 60 second mark. If there is only a few active accounts then after a long time someone will generate a block because the target will become very big. If you open the client and log with any funded account you can see a ticking timer in BLOCKS widget. It shows when the target will become greater than your hit.
So, what does it mean?
If I have two addresses with A and B coins and the maximum possible hit value is N (2^64) then probability that I will generate new block is
1 - (1-A/N)(1-B/N)=(A+B)/N - AB/N^2. But if I join these two addresses the probability of generating new block becomes (A+B)/N.
It gives serious incentive of joining your NXT with somebody else NXT (since you and other one will gain strictly more than separately). Apparently this implies of appearing one megapool that will control much more then 50% of all NXT.
300K for me please
NXT address: 12819855557255769883
I will send 0.3BTC from (BTC: 19tzeK4FQnNzp9Bkg6wgezBrb2eoeQLhgQ) when you agree.
NXT address: 12819855557255769883
I will send 0.3BTC from (BTC: 19tzeK4FQnNzp9Bkg6wgezBrb2eoeQLhgQ) when you agree.
BTC amount: 0.3
BTC address: 14oB2J2CsHDpVYMYegoBNgvpmBBsKAd6yt
300K for me please
NXT address: 12819855557255769883
I will send 0.3BTC from (BTC: 19tzeK4FQnNzp9Bkg6wgezBrb2eoeQLhgQ) when you agree.
NXT address: 12819855557255769883
I will send 0.3BTC from (BTC: 19tzeK4FQnNzp9Bkg6wgezBrb2eoeQLhgQ) when you agree.
BTC amount: 0.3
BTC address: 14oB2J2CsHDpVYMYegoBNgvpmBBsKAd6yt
Hi all,
Since I'm newbie I need to create several posts on this forum, so here is mine)
I've noticed that all known (to me) cryptocurrencies are strore full transaction history for every available "coin". So, is to store this history really necessary? A simple alt. way may be just to store current balances of every user. Actually it even seems to enough to strore one-way accumulator hash of all balances and send required for every node hash update when new block is generated.
Since I'm newbie I need to create several posts on this forum, so here is mine)
I've noticed that all known (to me) cryptocurrencies are strore full transaction history for every available "coin". So, is to store this history really necessary? A simple alt. way may be just to store current balances of every user. Actually it even seems to enough to strore one-way accumulator hash of all balances and send required for every node hash update when new block is generated.
If you can figure out how to do it without needing a blockchain, you'll have the only decentralized cryptocurrency in the world that doesn't require mining.
A solution in my signature.
I still don't see where could be the problem)
Everything is similar to the current implementation of btc. Each block contain hash of previous and hash of concatenation of the all balances and proof of work of this block.
The problem that I see is that each adress actually still need to remember last balance before last 256 blocks of each address (remember only self balances and hashes of concat. balances of each block is not sufficient). But nevertheless it still seems to be much less to store then each transaction.
Everything is similar to the current implementation of btc. Each block contain hash of previous and hash of concatenation of the all balances and proof of work of this block.
So block 123,456 shows I (or more correctly an address I have) have a balance of 100 BTC. How do you verify it? If all you have is the balance how do you know it is correct?
I can be sure that longest blockchain without its last 256 blocks is correct with prob > 1-2^(-256) (so it is easier to break some sha-256 from the network). When I get longest blockchain and transactions during last 256 blocks I can easily check if the transactions are correct and then check if the last 256 blocks are correct (that they are calculated from correct balances and check proof of work). The problem that I see is that each adress actually still need to remember last balance before last 256 blocks of each address (remember only self balances and hashes of concat. balances of each block is not sufficient). But nevertheless it still seems to be much less to store then each transaction.
I don't say that there no need of blockchain 
. Question is why there is need of transaction chain for every coin i.e. why balances information is not enough.
. Question is why there is need of transaction chain for every coin i.e. why balances information is not enough.Where does the balance information come from? Surely it would come from calculating all the transactions.
You need the transaction history to make sure that someone hasn't spent the same bitcoins twice. If you store balance information, you still need the transaction history to verify that the balances are correct.
Transaction chain shows proof of which address owns which coins, and tracking them back to their initial mining proves they are real coins. Without this transaction chain it would be considerably easier to make illegitimate coins.
If we store balances before the checkpoint and transactions only after checkpoint it seems to be as safe as the current bitcoin implementation (beacuse balance at the time of the checkpoint won't change even in the case of some forks). The double spents could be easily verified - it only need to check that the sum of transaction inputs less then the balance.Hi all,
Since I'm newbie I need to create several posts on this forum, so here is mine)
I've noticed that all known (to me) cryptocurrencies are strore full transaction history for every available "coin". So, is to store this history really necessary? A simple alt. way may be just to store current balances of every user. Actually it even seems to enough to strore one-way accumulator hash of all balances and send required for every node hash update when new block is generated.
Since I'm newbie I need to create several posts on this forum, so here is mine)
I've noticed that all known (to me) cryptocurrencies are strore full transaction history for every available "coin". So, is to store this history really necessary? A simple alt. way may be just to store current balances of every user. Actually it even seems to enough to strore one-way accumulator hash of all balances and send required for every node hash update when new block is generated.
.