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Show HN: Interactive implementation of the NIST Blockchain use case flow chart

brucemacd.github.io

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Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#11

Post by randaouser »

although sensitive data should never be written to a public ledger, that does not automatically disregard the need for a blockchain technology. Take a supply chain scenario where multiple control points would input data, however, none of the contributors trust any single touchpoint to maintain the datastore.

The senstivity issue can be overcome by submitting a cryptographic hash of the information (say sha256) and storing the encrypted data on ipfs. In future audits, one can reveal the unencrypted data and ensure the hashes match.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#12

Post by nootropicat »

village-idiot wrote: post #10
nootropicat wrote: post #5

>Data records, once written, are never updated or deleted? >Blockchains do not allow for modification of historical data. Consider a database. If that was true it wouldn't even be possible to send any tokens. Log of all past actions can't be deleted or updated, which is a quite different thing.

The log entries in a blockchain are supposed to be immutable. You can add new entries, but not change old ones.

It depends on how you define what a 'data record' is. State of a specific address can be changed and deleted if the contract is designed to allow it. It's directly equivalent to a normal database that keeps logs of all historical commands entered.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#13

Post by aeijdenberg »

randaouser wrote: post #11

although sensitive data should never be written to a public ledger, that does not automatically disregard the need for a blockchain technology. Take a supply chain scenario where multiple control points would input data, however, none of the contributors trust any single touchpoint to maintain the datastore. The senstivity issue can be overcome by submitting a cryptographic hash of the information (say sha256) and st…

Not quite as simple as a cryptographic hash alone - remember that if the set of possible inputs can be easily enumerated, then it's trivial to find the input data by brute force.

There are ways to work around this, for example objecthash[0] describes a small modification that prepends the input data with 32 bytes of random data before hashing in order to prevent this.

[0] https://github.com/benlaurie/objecthash#redactability

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#14

Post by Theodores »

Brilliant. I have found a use case for blockchain thanks to this tool. Who wants to go co-founder on my YC application for...

"Blockchain for nuclear weapons"

Any fan of Dr Strangelove should know that there is a problem with the system, it is not just the president's nuclear football that can bring on the omnicide that the people in CND are so scared of.

Blockchain for nuclear weapons - where could it go wrong?

It is an obvious use case, not a solution in search of a problem. I stand corrected with all my scepticism regarding blockchain. We don't need pesky INF treaties, we can just go with smart contracts and have only the president able to launch that decapitation strike rather than some rogue general.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#15

Post by decentralised »

village-idiot wrote: post #10
nootropicat wrote: post #5

>Data records, once written, are never updated or deleted? >Blockchains do not allow for modification of historical data. Consider a database. If that was true it wouldn't even be possible to send any tokens. Log of all past actions can't be deleted or updated, which is a quite different thing.

The log entries in a blockchain are supposed to be immutable. You can add new entries, but not change old ones.

We often talk about "blockchain as a database" but don't clarify what type of data we are discussing.

In second generation blockchains like Ethereum there's a difference between world state and ledger data. Only the Ledger data (record of state transitions) is immutable by design.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#16

Post by browsercoin »

village-idiot wrote: post #10
nootropicat wrote: post #5

>Data records, once written, are never updated or deleted? >Blockchains do not allow for modification of historical data. Consider a database. If that was true it wouldn't even be possible to send any tokens. Log of all past actions can't be deleted or updated, which is a quite different thing.

The log entries in a blockchain are supposed to be immutable. You can add new entries, but not change old ones.

so what's wrong with Datomic? why do people insist on using blockchain?

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#17

Post by ketzu »

randaouser wrote: post #11

although sensitive data should never be written to a public ledger, that does not automatically disregard the need for a blockchain technology. Take a supply chain scenario where multiple control points would input data, however, none of the contributors trust any single touchpoint to maintain the datastore. The senstivity issue can be overcome by submitting a cryptographic hash of the information (say sha256) and st…

One problem of this solution is you can not verify the write in the first place, as the encrypted data is no longer publicly verifiable.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#18

Post by quellobiondo »

browsercoin wrote: post #16
village-idiot wrote: post #10

Earlier quoted context omitted.

The log entries in a blockchain are supposed to be immutable. You can add new entries, but not change old ones.

so what's wrong with Datomic? why do people insist on using blockchain?

The point is on the ownership of the database and the trust among participants. In Datomic there is a single owner that has full control on the data (probably you, or a company that you fully trust). In the blockchain use-cases there are multiple parties that depend on the data, and no one of them is trusted enough to have full control on the database. (trust-less scenarios) Apart from Bitcoin[0] check out the original trustless timestamping service proposal [1].

[0] https://bitcoin.org/bitcoin.pdf [1] H. Massias, X.S. Avila, and J.-J. Quisquater, "Design of a secure timestamping service with minimal trust requirements," In 20th Symposium on Information Theory in the Benelux, May 1999.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#19

Post by davidy123 »

brucemacd wrote: post #4
cwyers wrote: post #2

I think there's a bug in this. If I answer "Will data records ever need to be updated or deleted once they are written?" with "No" it says "You Don't Need a Blockchain Blockchains do not allow for modification of historical data. Consider a database." It seems like blockchains actually meet that requirement per my entry?

Just fixed the wording to match the actual NIST flowchart. Thanks.

I realize this isn't a life's work, but can you support the back button? Some of the questions are double-negative-ish, or maybe I'm just not a morning person, either way the back button to revise answers without having to go through the whole thing again would be useful.

Re: Show HN: Interactive implementation of the NIST Blockchain use case flow chart

#20

Post by village-idiot »

browsercoin wrote: post #16
village-idiot wrote: post #10

Earlier quoted context omitted.

The log entries in a blockchain are supposed to be immutable. You can add new entries, but not change old ones.

so what's wrong with Datomic? why do people insist on using blockchain?

To be fair, you can modify datomic, there’s a mutable delete operation so that you can comply with legal requirements to delete data.
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