
Why Can't Crypto Mining be used to Power other things? (e.g. video rendering) - cxejohns
I was just reading about various crypto altcoins and wondering, would it be possible to turn the processing used for bitcoin mining into something more useful? If so, what? And if not, why not?
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rajnathani
There's Gridcoin [1] which states "which securely rewards volunteer computing
performed on the BOINC platform". Though I personally am not aware of how
successful it has been so far.

With regards to video rendering, cbhl correctly brings up the trust and
latency issue. I feel the latency issue is particularly important, as even AWS
recently announced their Local Zones data centers [2] for "highly-demanding
applications that are particularly sensitive to latency" with an example
clearly stated for the large video production studios in LA: "3D modeling &
rendering, video processing (including real-time color correction), video
streaming, and media production pipelines".

Personally, I feel there are latency insensitive applications such as protein
folding which could benefit from proof-of-work, and there does seem an attempt
at a crypto coin [3] for this. However I'm not too sure as to whether it's the
lack of good execution for these projects not taking off, or if there's a more
intricate sociological or other explanation for it.

[1] [https://gridcoin.us/](https://gridcoin.us/)

[2] [https://aws.amazon.com/blogs/aws/aws-now-available-from-a-
lo...](https://aws.amazon.com/blogs/aws/aws-now-available-from-a-local-zone-
in-los-angeles/)

[3] [https://foldingcoin.net/](https://foldingcoin.net/)

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cbhl
The last time I considered this:

\- Most grid/cluster-based video rendering systems assume trust. Shared
filesystems, central nodes that allocate work, users submit jobs to the
central node. This trust allows for lower overhead, as each unit of work only
needs to be processed once. (By comparison, with blockchains, you need to wait
for n copies of the work to be done and compare them to verify that a bad
actor hasn't submitted garbage; these are "confirmations".)

\- One key property of cryptocurrencies is resilience in the face of bad
actors. In particular, you want each node to independently be able to come to
consensus without trusting a central node. (Otherwise, you would just devise a
scheme that trusts a central node, such as a Bank.) So if you want to replace
Proof of Work or Proof of Stake with a "useful" task, you have to devise a
scheme that retains the property of "consensus without trust", while also
providing "useful" work (that is, correct video rendering results, in a
reasonable response time). I'd look up "51% attack", as well as the documents
describing the design of scrypt
([https://www.tarsnap.com/scrypt.html](https://www.tarsnap.com/scrypt.html))
and other password hashing functions to get a sense of the attack modes you
have to design for.

\- Assuming you come up with a good scheme, you then need to convince the rest
of the world to adopt it. (Note that some actors have hardware that is
optimized for the task defined by Bitcoin. Also, if your user base is too
small, then it's trivial to 51% attack by just buying more computers than
you.)

I don't think it's impossible; I just don't think it's cost-effective (versus
just buying and building a grid/cluster with trusted nodes).

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cxejohns
Thanks for the breakdown. If I have it right, it sounds like block creation is
an inherently 'useless' process. One could make it useful, but not in a truly
integral way, given how normal, centralized data processing works.

~~~
cbhl
I don't know if 'useless' is the right word.

My understanding is that a block is simply a page of the distributed ledger
(that is, a list of transactions), plus a hash preimage problem. (What value
do I append to this data, such that the hash function returns some pre-
specified value?)

That such a computation is expensive to compute (but cheap to verify) is core
to some of the properties of cryptocurrency. The alternatives provided by
normal data processing are cheaper and faster (if you have trust).

If you make the computation cheaper, then financial transactions in the ledger
are reversible. But if you make the cheap task expensive, then people will
just pay for regular grid computing because it's cheaper.

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jki275
primecoin did this. There might have been others.

