It's cool that Galois got this contract. They're a very nice Haskell shop out of Seattle responsible for projects like Copilot and Cryptol.
Out of Portland, actually.
Yep, sorry about that!
Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
51–58 of 58 posts
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#52Earlier quoted context omitted.
It doesn't work that way. The hashes can simply indicate proof of tampering, so instead you get (some) assurance that there was no tampering in the evidence. Attackers can still modify the data. For example, if they modify the feed before the hash of the feed is introduced into the blockchain. Edit; Security at that level is extremely difficult as their adversaries are much more powerful and well funded. I can unders…
Because time is baked into the process, and there are alternate means of establishing the time of events that relate to treaty verification, actually it would work this way, at least with respect to a hypothetical video feed. I have intimate knowledge of treaty verification procedures and methods, and worked in collections relating to these activities for the intelligence community. The fact is that there is no video…
It just seems like you're expressing contest of granularity. A simple example is a feedback loop that would still have the process be deterred by some time from collecting evidence, and from being detected. The process just prevents to a certain degree the tampering of evidence once collected.
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#53Earlier quoted context omitted.
(I work for Guardtime; I’m happy to answer any questions.) Some online resources might not make it very clear, but the KSI blockchain is indeed a blockchain; for example, new blocks are released periodically (1 block per second on average), and the new blocks contain hashes of the previous blocks, among other things. Then, blocks get distributed around so that users can verify their data against these blocks, etc.
Most people associate "blockchains" with a protocol by which the "blocks" are inserted. Usually these things revolve around proof-of-work, proof-of-stake, proof-of-space, fairness criteria, etc. I think everyone gets that the Guardtime product is hashtree. From a formal verification perspective, the critical behavior is probably in the protocol, and most likely not the implementation of the datastructure or database.
One way to look at it is that KSI is a proof of stake blockchain where the stakeholders are (mostly) fixed. Often people would call that a private blockchain (or a consortium blockchain), to use the terminology from the following article:
https://blog.ethereum.org/2015/08/07/on-public-and-private-b...
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#54Earlier quoted context omitted.
(I work for Guardtime; I’m happy to answer any questions.) Some online resources might not make it very clear, but the KSI blockchain is indeed a blockchain; for example, new blocks are released periodically (1 block per second on average), and the new blocks contain hashes of the previous blocks, among other things. Then, blocks get distributed around so that users can verify their data against these blocks, etc.
> 1 block per second on average What stops a double-spend or other attacks like that in a 1-second timeframe? The 10 minute threshold of Bitcoin was chosen under belief that the network would be settled after roughly 10 minutes.
The speed comes from the fact that private and consortium blockchains tend not use Proof of Work (at least not as the only algorithm; you could mix and match, if you wanted to). Instead, such blockchains tend to use voting-based protocols (e.g. Proof of Stake), where a certain subset of nodes are trusted with voting rights, who together vote to approve the next block. In some systems you also have automatic punishments built in to incentivise correct behaviour (i.e., if someone attempts to fork a blockchain --- for example by voting for 2 conflicting forks -- and if other nodes see any evidence of that, the node who attempted the fork could automatically lose their rights as a trusted validator, and may also automatically lose a lot of money or face legal fees.)
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#55Earlier quoted context omitted.
(I work for Guardtime.) KSI verification is meant to be decentralised; that is, no single (centralised) entity should have the ability to, for example, create fake timestamps. You can deploy KSI in various ways, so there can be, for example, one entity who controls access to the blockchain (but for example they still cannot fake any evidence).
Right, it appears you can have multiple physical tamper-protected boxes that agree with each other, which makes it federated, but not decentralized.
I tend to subscribe to the definitions laid out in the following article:
https://blog.ethereum.org/2015/08/07/on-public-and-private-b...
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#56For those who are interested in an underpinnings of KSI:
https://eprint.iacr.org/2014/321.pdf
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#57Earlier quoted context omitted.
Most people associate "blockchains" with a protocol by which the "blocks" are inserted. Usually these things revolve around proof-of-work, proof-of-stake, proof-of-space, fairness criteria, etc. I think everyone gets that the Guardtime product is hashtree. From a formal verification perspective, the critical behavior is probably in the protocol, and most likely not the implementation of the datastructure or database.
One way to look at it is that KSI is a proof of stake blockchain where the stakeholders are (mostly) fixed. Often people would call that a private blockchain (or a consortium blockchain), to use the terminology from the following article: https://blog.ethereum.org/2015/08/07/on-public-and-private-b...
Thanks for that clarification! It is a great pleasure to talk with an knowledgeable person like you.
Re: Darpa Contract Awarded to Verify Blockchain-Based Integrity Monitoring System
#58Earlier quoted context omitted.
The signature for your data that has been signed is a chain of hashes which is used to calculate back to the merkle root. Wikipedia defintion of blockchain[1] > A blockchain consists of blocks that hold batches of valid transactions. Each block includes the hash of the prior block in the blockchain, linking the two. The linked blocks form a chain [1] https://en.wikipedia.org/wiki/Blockchain_(database)
The very next paragraph describes blockchain databases as peer-to-peer protocols with some form of scoring algorithm to decide which blocks are part of the chain.
This has now been answered by someone from the team