[tbb-bugs] #28326 [Applications/Tor Browser]: Tor Browser for PPC64LE

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#28326: Tor Browser for PPC64LE
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 Reporter:  power9                    |          Owner:  tbb-team
     Type:  enhancement               |         Status:  new
 Priority:  Medium                    |      Milestone:
Component:  Applications/Tor Browser  |        Version:
 Severity:  Normal                    |     Resolution:
 Keywords:  tbb-rbm                   |  Actual Points:
Parent ID:                            |         Points:
 Reviewer:                            |        Sponsor:
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Comment (by teor):

 Replying to [comment:3 gk]:
 > Replying to [comment:2 teor]:
 > > Tor doesn't support PPC, because its MUL instruction is not constant-
 time.
 > > It's really hard to write secure crypto without a constant-time MUL.
 > >
 https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/SupportedPlatforms
 >
 > Good to know. FWIW: there are Debian packages for that platform, though.

 That's fine: Tor is open-source, so Debian can maintain a PPC build of Tor
 if they want.

 We just won't put any effort into Tor on PPC, because:

 >  If (nearly?) all users on a platform are insecure, it's also good
 candidate for Rejected.

 > PPC (The MUL instruction isn't constant-time, thus many common
 cryptographic operations on these systems are subject to even the most
 trivial side-channel attacks.)

 Replying to [comment:4 power9]:
 > That's mean we never see Tor Browser on PPC?

 The Tor Browser team can maintain a PPC build of Tor if they want. But PPC
 has trivial cryptographic side-channel attacks. So a PPC Tor Browser might
 not meet Tor Browser's security standards.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28326#comment:5>
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