Topic: NXT :: descendant of Bitcoin - Updated Information - page 1715. (Read 2761645 times)

I don't see how someone buying a store item is in any way a problem for nxt or even BTC right now. Can someone please enlighten me?

thx, ricot,

ok, understood. usefull for users typing in account numbers but this doesn't answer my question.
this doesn't help to prevent sending funds to hiberNXT, or does it and if, could you please explain how?

as said, i am currently on this, therefore i would like to understand the whole procedure.
from what i see the main problem is to copy or even type a number to send funds to
which is not the intended number and therefore the funds are lost in hiberNXT.

is this what we are talking about?

NextCoin card payment

Good day to all participants. Thank you all for the development NextCoin

If you look forward NXT can compete with Visa.

When NXT is connected to the card, will not able to drive the key length for the transaction when buying in a store, it is troublesome.

I suggest in the future to include NXT, and think how you can improve the payment for goods in stores using NXT without a key, for example, use a pin code.

thx, ricot,

ok, understood. usefull for users typing in account numbers but this doesn't answer my question.
this doesn't help to prevent sending funds to hiberNXT, or does it and if, could you please explain how?

as said, i am currently on this, therefore i would like to understand the whole procedure.
from what i see the main problem is to copy or even type a number to send funds to
which is not the intended number and therefore the funds are lost in hiberNXT.

is this what we are talking about?

Please see my thread about that in the other forum: https://forums.nxtcrypto.org/viewtopic.php?f=17&t=524
We can do a lot better than merely detecting if the user made an error. With the method presented there, we can correct what the user typed. - That's 2nd gen. :p

Gang,

Would appreciate Chinese speakers looking this over for errors. Also, I know nothing about leading/kerning/spacing with Chinese characters and what's appropriate.



Also, full-size PDF is here

EDIT: sorry, forgot to credit Miramare from the nextcoin.org forum for supplying Chinese text.

it just a simple example.

acct: 209832084023840384023
MD5 & SHA Checksum: DfwSgeH    // from MD5("accountid")

so the new account: DfwSgeH-209832084023840384023  // from  substr(MD5("accountid"),6)+ "- accountid"

//substr(MD5("209832084023840384023"),6)=="DfwSgeH"
if( substr(MD5("209832084023840384023"),6)==substr("DfwSgeH-209832084023840384023",6) ) it is available..
else unavailable.

Each new account is password and userid combination : password-userid

An interesting thread about hardware Nxt wallet - https://nextcoin.org/index.php/topic,728.msg27895.html#msg27895

But there are 300 nodes, not 10k:

http://peerexplorer.com/

it just a simple example.

acct: 209832084023840384023
MD5 & SHA Checksum: DfwSgeH    // from MD5("accountid")

so the new account: DfwSgeH-209832084023840384023  // from  MD5("accountid")+ "- accountid"

if( MD5("209832084023840384023")=="DfwSgeH"  ) it is available..
else unavailable.

thanks for this example coolfish,
could you explain further please how this checksum approach can verify account available?

CfB,

How many mistakes did I make with the following?

*****
In order to understand Transparent Forging, we must first understand the forging process itself. The goal of NXT forging is to give a chance to each account proportional to the amount of NXT in the account. A small amount of randomness is required to eliminate the possibility of attacks based on knowing the far future forgers, but the near future should be as close to deterministic as possible to allow significant reduction in network bandwidth usage. These apparently contradictory requirements are satisfied by the following code from the Jan 3rd, 2014 source code release:

    Account account = unlockedAccountEntry.getKey();
    User user = unlockedAccountEntry.getValue();
    Block lastBlock = Block.getLastBlock();
    if ( lastBlocks.get(account) != lastBlock )
    {
        byte[] generationSignature = Crypto.sign(lastBlock.generationSignature, user.secretPhrase);
        byte[] generationSignatureHash = MessageDigest.getInstance("SHA-256").digest(generationSignature);
        BigInteger hit = new BigInteger(1, new byte[] {generationSignatureHash[7], generationSignatureHash[6], generationSignatureHash[5], generationSignatureHash[4], generationSignatureHash[3], generationSignatureHash[2], generationSignatureHash[1], generationSignatureHash[0]});
        lastBlocks.put(account, lastBlock);
        hits.put(account, hit);    // jl777: hit now contains a deterministic but pseudo-random number
        JSONObject response = new JSONObject();
        response.put("response", "setBlockGenerationDeadline");
        response.put("deadline", hit.divide(BigInteger.valueOf(Block.getBaseTarget()).multiply(BigInteger.valueOf(account.getEffectiveBalance()))).longValue() - (getEpochTime(System.currentTimeMillis()) - lastBlock.timestamp));
        user.send(response);
    }
    int elapsedTime = getEpochTime(System.currentTimeMillis()) - lastBlock.timestamp;
    if ( elapsedTime > 0 )
    {
        BigInteger target = BigInteger.valueOf(Block.getBaseTarget()).multiply(BigInteger.valueOf(account.getEffectiveBalance())).multiply(BigInteger.valueOf(elapsedTime));   // jl777: chance proportional to effective balance
        if ( hits.get(account).compareTo(target) < 0 ) {    // jl777: as time elapses the target gets larger, eventually triggering the acct closest to target.
            account.generateBlock(user.secretPhrase);
        }
    }

Due to the deterministic way the chances are calculated, it is possible to predict which acct will forge the next block and also when it will be forged. Since the hit value is deterministic, a person with multiple accounts can calculate which one has the best chance of forging the next block and transfer all the NXT to that acct. This is why the effective balance is used instead of the actual balance. A time delay from when an account is funded and also a time delay from when funds are transferred reduces the effective amount to eliminate NXT shuffling attacks.

By storing all of the hit values from all the accounts, if each node also knew which accounts are also actively forging, it will be possible for all nodes to predict which acct will forge the near future blocks. Due to variations in clocks and changing of active forging accts, it is not 100% accurate, but this is by design. There needs to be some error factor to prevent an attacker from calculating who will forge blocks in the far future to avoid the NXT shuffling attacks. As long as the prediction rate is close to 100%, the network traffic is reduced dramatically allowing for near realtime processing of thousands of transactions.

Transparent forging allows for a centralized action in a decentralized network. This is the fundamental breakthrough that NXT incorporates.
******

James

A lot of good thoughts from rickyjames. Everybody should read it.

nxt system should have a validation function to verify the account is available.

e.g:
acct: 209832084023840384023
MD5 & SHA Checksum: DfwSgeH

so the new account: DfwSgeH-209832084023840384023

Check the MD5 or SHA to verify the account available..

.... The last thing a person with a cellphone is going to do is sit there and type in a 50 digit uppercase-lowercase password to buy a candy bar with NXT. ...