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Are there any post-quantum blind signature algorithms? Since hash-based blind signature schemes have proven to by impossible (based on a response to this question) is this an active area of research or is it only feasible by using extraordinarily large pre-quantum algorithm keys?

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This is adressed for example in Lattice-based Blind Signatures by Markus Rückert, 2008. I only had a quick glance, and it seems there is a construction for building blind signatures based on lattice problems.

But this isn't surprising, because lattice problems can be used for:

  • building post-quantum encryption schemes, key exchange, signatures, etc.
  • building fully-homomorphic encryption schemes. Such a system preserves a lot of algebraic structure (in contrast to OWFs), and it should be quite easy to use this to create blind signatures (which are often based on some semi-homomorphic property)
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    $\begingroup$ Are there non-lattice post-quantum schemes? The lattice stuff looks promising, but from what I understand it is nowhere near proven to be reliable (thus the SPHINCS and other hash-based signature schemes.) "Reliable" meaning actually quantum safe - because there has been a lot of talk that it might be susceptible to quantum algorithms if some traits people aren't sure it doesn't have are proven. $\endgroup$ – CoryG Jan 9 '18 at 16:13

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