[tor-bugs] #19872 [Core Tor/Tor]: Introduce prefixed sign/verify functions

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#19872: Introduce prefixed sign/verify functions
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:
     Type:  task                                 |         Status:
                                                 |  needs_review
 Priority:  Medium                               |      Milestone:  Tor:
                                                 |  0.2.???
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  029-proposed, tor-hs,                |  Actual Points:  0.3
  TorCoreTeam201608                              |
Parent ID:                                       |         Points:  0.3
 Reviewer:  dgoulet                              |        Sponsor:
                                                 |  SponsorR-can
-------------------------------------------------+-------------------------
Changes (by asn):

 * status:  needs_revision => needs_review


Comment:

 Replying to [comment:3 dgoulet]:
 > Two small things:
 >
 > * Need documentation on the returned value that is 0 on success and -1
 on error. Either that or we document the return value of `ed25519_sign()`
 which has none documented in `crypto_ed25519.c`.
 >
 > * There is lots of `strlen(prefix_str)`, could be nicer to do it once
 and then use it. Also, is there a chance that we would like to use this
 for a non string prefix? Would it be bad to just go with `uint8_t *` and
 pass the prefix len as param as well even though it's a string?

 Pushed a fixup commit that addresses your comments!

 I did not change the function prototype to accept non-string prefixes
 since we don't need those yet. If we ever need them, let's do the change.
 Let me know if you think this is a stupid decision.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/19872#comment:5>
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