Masp vp parallel verification

[grarco]

Describe your changes

Closes #2959.

Parallelize the masp vp verification step.

Currently this doesn't work. The parallel verification process succeeds for every check (even the proofs) except for the signature one and more specifically for the final check on the result point being of small order (https://github.com/ZcashFoundation/reddsa/blob/56d52195608f3830f027f7109176a30175a5c1aa/src/batch.rs#L272)

To get batch signature verfication to work, the following three issues needed fixing:

• In computing the nonce for RedDSA, the concatenation of public key and msg does not need to be handled in the masp crate, this is done automatically by From<...> impl
• The H* function which hashes data to elliptic curve points has a different personalization ("Zcash_RedjubjubH" vs "MASP__RedjubjubH")
• The batch verification assumes a different basepoint than the MASP does.

The latter two issues are the most inconvenient. We can either change our personalization and basepoints to match the RedDSA assumptions, or we must fork that crate

Indicate on which release or other PRs this topic is based on

v0.37.0

Checklist before merging to draft

• I have added a changelog
• Git history is in acceptable state

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 78 lines in your changes are missing coverage. Please review.

Project coverage is 53.94%. Comparing base (6dc1612) to head (15affec).
Report is 2 commits behind head on main.

Files	Patch %	Lines
crates/sdk/src/masp.rs	0.00%	78 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2972      +/-   ##
==========================================
+ Coverage   53.89%   53.94%   +0.05%     
==========================================
  Files         314      314              
  Lines      105704   105597     -107     
==========================================
  Hits        56968    56968              
+ Misses      48736    48629     -107     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.