Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
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Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
1–10 of 44 posts
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#2I've been interested in the benefits of something like http://www.guardtime.com/ for a while. Using a distributed network like Bitcoin seems perfect.
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#3Discussion from yesterday's submission, with 75 comments: https://news.ycombinator.com/item?id=6809929
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#4This makes me think of another thing I was wondering about -- can some entity that doesn't like having Bitcoin around for whatever reason, DDoS it by filling it with meaningless transactions.
Maybe just setting up 100 addresses and constantly transferring small payments between them, filling the transaction history with garbage. Is that possible, and is there any protection against that?
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#5"This is why the bitcoins sent in this special transaction are unspendable, as the addresses are being generated from the document's hash fragments instead of from a private ECDSA key."
I hadn't realised before that this means that you can provably "destroy" bitcoins. That is, you can "prove" that a certain bitcoin amount will never be spent again by anyone including yourself...
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#6This makes me think of another thing I was wondering about -- can some entity that doesn't like having Bitcoin around for whatever reason, DDoS it by filling it with meaningless transactions. Maybe just setting up 100 addresses and constantly transferring small payments between them, filling the transaction history with garbage. Is that possible, and is there any protection against that?
Transaction prioritization[1] and transaction fees already rate limit stuff like that, and patches to the clients used by major mining pools may be able to fix it permanently.
1. priority = sum(input_value_in_base_units * input_age)/size_in_bytes
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#7This makes me think of another thing I was wondering about -- can some entity that doesn't like having Bitcoin around for whatever reason, DDoS it by filling it with meaningless transactions. Maybe just setting up 100 addresses and constantly transferring small payments between them, filling the transaction history with garbage. Is that possible, and is there any protection against that?
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Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#8Adding lots of data to the transaction logs is one easy DDoS. Do so many transactions that the logs get to be larger than fit on most systems. With multiple Gigs of data already required, if someone was evil they could up the volume and keep people out of the game by making sure that that there were over a terabyte of transaction logs. Most machines won't have that kind of storage and would "fall off" the network.
Patient0 mentioned before I got to post this, the other attack I know would work. Destroying tokens. But it is a bit more complex than he mentions, but you can actually generate ECDSA key's that will work for one transaction, and then never again. A one time spend token that then self destructs for the person you paid.
I haven't been able to build anything that would work for two transactions. Which would be the most useful since you'd have a delayed "poison coin" but I don't see any reason it isn't computationally possible.
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#9"This is why the bitcoins sent in this special transaction are unspendable, as the addresses are being generated from the document's hash fragments instead of from a private ECDSA key." I hadn't realised before that this means that you can provably "destroy" bitcoins. That is, you can "prove" that a certain bitcoin amount will never be spent again by anyone including yourself...
Yeah, the fact that bitcoins can be permanently destroyed is a little bit worrying, one of BTC's benefits is it's cap. What's the economical consequences of these coins being destroyed?
Re: Proof of Existence: Storing Hashed Files in the Bitcoin Block Chain
#10This makes me think of another thing I was wondering about -- can some entity that doesn't like having Bitcoin around for whatever reason, DDoS it by filling it with meaningless transactions. Maybe just setting up 100 addresses and constantly transferring small payments between them, filling the transaction history with garbage. Is that possible, and is there any protection against that?
Transaction prioritization[1] and transaction fees already rate limit stuff like that, and patches to the clients used by major mining pools may be able to fix it permanently. 1. priority = sum(input_value_in_base_units * input_age)/size_in_bytes
What determines the size_in_bytes value?
In general, let's say a govt agency get assigned an $18.5m budget to break the Bitcoin currency as much possible, what could their plan of attack be, i.e. spend that money in the most efficient way possible? Create a large ring of wallets and send tiny payment around the ring? Create less wallets but send large payments between them?