The huge majority of stratum 1 NTP nodes are getting their feed from GPS, so trust in NTP is essentially trust in the US Government.

Feature request:  A way to change a worker's password.

Because I'm helpful.

Maybe some day.  Not today, not soon.

The idea is not to kick them off the network.  It is to make it harder to win block races.

If there is an honest disagreement about the block chain, the version that is believed by more nodes is likely to win eventually.  That means that there is an advantage to being well connected.

If you are intending to attack the chain, you will want to have as many connections as you can, to get as much of the network on your side as possible.  This proposal makes it more difficult for an attacker to remain well connected.  Not impossible, of course, just more difficult.

I'm a networking guy, so I propose that we use the term "chain flapping" or merely "flapping" to describe the phenomena evident when two long term competing branches are fighting for control of the chain.  Look up route flapping, if you aren't familiar with the term already.

In the case of an attacker with a lot of hashing power, since the attacker never has a 100% certain chance of getting their block out first, there will be times when an honest node will get a valid block out first, and the attacker will then have to publish multiple blocks to regain control.  This is an inevitable result of this type of attack.

I propose a countermeasure.  Every time a node is forced to reshuffle because a side chain grows longer than the main chain, the peer that caused the shuffle is noted.  If a third arrives within a certain timeframe, that link is considered to be flapping, and will be disconnected.

This will have little effect on middle nodes, since on average they will only need to pass the block to a small fraction of their peers, and the remaining connections will not be closed.  The attacker, however, will have to pass it to many peers, and will lose many connections.

There is more, but I've gotta run.  Gonna get drunk and watch game 7, but not necessarily in that order.  Heh, I'm in such a hurry I haven't even had time to search on this.  Hope I'm not rehashing something that was sorted out years ago.

Agreed.

The time to find a block is not a linear function of your hashing speed, it is a probabilistic process.  Having 10% more power than the other guy doesn't mean you find blocks 10% faster, it means that you have a ~5% chance of finding it before him.

Say that you fraction of the global networking power is X, where 0 <= X <= 1;

The probability that you will be able to do this for one block is X
The probability that you will be able to do this for two blocks is X^2
The probability that you will be able to do this for three blocks is X^3
The probability that you will be able to do this for four blocks is X^4
Etc...

Actually, those are the high end estimates.  In reality, you will need another factor, Y, to correct for the portion of the network that believes in the attack chain.  Over time, Y will get smaller and smaller.

Since this topic keeps coming up over and over again, I'm going to propose a potential solution: every time a node reshuffles, they should make a note of which peer it came from.  More than three reshuffles from the same peer in like 24 hours, and that node is dropped.

Why would anyone accept a physical coin from you that you can revoke?

bitcoin.org -> Wiki / Help -> Mining -> Mining hardware comparison

+1

You would need not just 50% of the world's hashing power, but closer to 95%+ of it if you wanted to pull off any meaningful BTC scam.  That means you would need twenty times more hashing power than the rest of the world combined.

I'm hardly an early adopter, joining up 9 whole days ago.  What made me sarcastic and condescending (not to mention bitter) was answering this exact same question about 30 times.


You'll need to scale that to the GPU you are planning to buy.  If, for example, you get a 5850, you can expect about 300 Mhash/sec out of it, so it would earn about 1.95 * (300/700) = 0.835 * 50 = 41 BTC.  Even that estimate is probably very high.

Yup.  Go for it.  You've managed to ignore all of the dozens of other threads asking this same question, plus all of the wiki pages, guides, calculators, spreadsheets and other utilities that could help you make a ration decision.  Based on this, and because I'm sick of doing simple math for people, I feel that you have the true believer spirit that is necessary to be a successful miner.

Gold and silver coins are the perfect physical companion to bitcoins.  They have many desirable characteristics in common.

Heh.  Those errors are intentional.  There are more hidden too, including a really big one.

I could have gone more realistic, but I figured I'd go for the authentic 419 flavor this time.

You mean other than ArtForz?

Subject: Dear Respected One,

Dear Respected One,

GREETINGS,

Permit me to inform you of my desire of going into business relationship with you. I got your contact from the International web site directory. I prayed over it and selected your name among other names due to it's esteeming nature and the recommendations given to me as a reputable and trust worthy person I can do business with and by the recommendations I must not hesitate to confide in you for this simple and sincere business.

I am Wumi Abdul; the only Daughter of late Mr and Mrs George Abdul. My father was a very wealthy cocoa merchant in Abidjan,the economic capital of Ivory Coast before he was poisoned to death by his business associates on one of their outing to discus on a business deal. When my mother died on the 21st October 1984, my father took me and my younger brother HASSAN special because we are motherless. Before the death of my father on 30th June 2008 in a private hospital here in Abidjan. He secretly called me on his bedside and told me that he has a sum of 12.500.000 BTC (Twelve Million, five hundred thousand bitcoins) left in a secure wallet.

He also explained to me that it was because of this wealth and some huge amount of bitcoins his business associates supposed to balance his from the deal they had that he was poisoned by his business associates, that I should seek for a God fearing foreign partner in a country of my choice where I will transfer these bitcoins and use it for investment purpose, (such as real estate management).

Sadly, he died while he was telling me the public key that matches the account, so some advance funding will be required to crack the remaining 43 bits of the private key. Sir, we are honourably seeking your assistance in the following ways.

1) To provide a bitcoin address where these bitcoins will be transferred to once the key recovery is complete.

2) To serve as the guardian of this since I am a girl of 16 years.

3) To provide an advance of 1.000 BTC (One thousand bitcoins) to be used to purchase computers that will be used to search for the remainder of the private key.

Moreover Sir, we are willing to offer you 15% of the sum as compensation for effort input after the successful recovery and transfer of this fund to your designate account. please feel free to contact ,me via this bitcoin address 1N8ZXx2cuMzqBYSK72X4DAy1UdDbZQNPLf

Anticipating to hear from you soon.
Thanks and God Bless.
Best regards.
Miss Wumi Abdul

It's only like 50,000 blocks back.  OCD hath its privileges.

His loss was pretty easy to find.  There aren't many transactions like it.  Finding one specific .01 transaction would be a lot harder.  You'd have to look at something else that you know, like one of the addresses, or the transaction ID.

You can click all the way back to the genesis block by using the Previous Block links.  Stone Man posted about the loss here on the forums the next day.