The state of the art of blind signature schemes
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In my research, so far I've found that most blind signature schemes are not quantum resistant. This means a quantum computer can crack the scheme using an advanced algorithm to invalidate the security premises the blind signatures are based on. This is similar to how Shor's algorithm can run on a quantum computer or other forms of cryptography can be broken on a quantum computer.

In my previous post I offered an [idea](https://steemit.com/steemit/@dana-edwards/a-privacy-preserving-reputation-system-is-possible-on-steemit) for a privacy preserving reputation system to be built on top of Steemit. This system I described here, utilizes a blind signature technique from Okamoto which is very much like a mechanism to allow anonymous voting. This is basically a mechanism which would decouple the reviews from the reviewers in an e-commerce use case and this is necessary for e-commerce but also have benefits for other possible features.

The problem? Quantum resistant blind signatures may not work using the Okamoto scheme. 

Enter the State of the Art Error Correcting Code based Blind signature scheme
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The security of this coding scheme is equivalent to the security of Niederreiter PKC. What is Niederreiter PKC? Niederreiter PKC is a public key encryption scheme based on error correcting codes. It's an alternative to the RSA or typical public key cryptography schemes we see. 

>The blind signature scheme is based on Niederreiter PKC, 
so  the  security  of  the  proposed  signature  scheme  is  up  to 
the security of Niederreiter PKC

What you can take away from this security analysis in the research papers is that Niederreiter PKC is resistant to quantum crypt-analysis attacks. In fact, by all currently known methods it is unbreakable. So for Steemit, this particular alternative crypto scheme may be of great value for enhancing privacy without the long term risk of a well financed quantum super computer trying to attack it.


Conclusion
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Any sort of voting, reviewing, or rating scheme on Steemit ultimately will have to rely on a blind signature scheme. If a blind signature scheme must be chosen then the state of the art is going to provide quantum resistance. This post is to reveal the research on the state of the art and show that a quantum resistant blind signature scheme is possible.


References

Repka, M. (2014). McEliece PKC calculator. Journal of Electrical Engineering, 65(6), 342-348.
Ye, J., Ren, F., Zheng, D., & Chen, K. (2015). an Efficient Blind Signature Scheme based on Error Correcting Codes.

If you would like to put this post in context, please see my previous post!
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 - [A Privacy Preserving Reputation System is possible on Steemit](https://steemit.com/steemit/@dana-edwards/a-privacy-preserving-reputation-system-is-possible-on-steemit)