[tor-bugs] #28634 [Core Tor/Tor]: Design a useful padding machine that we can enable

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#28634: Design a useful padding machine that we can enable
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:  (none)
     Type:  defect                               |         Status:
                                                 |  needs_review
 Priority:  Very High                            |      Milestone:  Tor:
                                                 |  unspecified
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  wtf-pad, tor-relay, tor-cell,        |  Actual Points:
  padding, 041-proposed                          |
Parent ID:  #28632                               |         Points:  4
 Reviewer:  mikeperry                            |        Sponsor:
                                                 |  Sponsor2
-------------------------------------------------+-------------------------
Changes (by asn):

 * status:  new => needs_review


Comment:

 OK I have an initial PoC here, as well as a spec patch:
 https://github.com/torproject/torspec/pull/72

 Check out the code here:
 https://github.com/torproject/tor/pull/868

 I'm setting this to needs_review to receive some comments from Mike.
 I'd also like some suggestions on how to do the bandwidth overhead
 analysis in the spec.

 Thanks!

 Here is how an intro point circuit looks like with this patch in chutney
 (had to change the latency to fit chutney):
 {{{
 IP circuit 6 was created at 20:49:49.973
 Relay cells:
 0: 20:49:49.978 -> EXTEND2
 1: 20:49:50.000 <- EXTENDED2
 2: 20:49:50.001 -> EXTEND2
 3: 20:49:50.023 <- EXTENDED2
 4: 20:50:25.520 -> PADDING_NEGOTIATE
 5: 20:50:25.520 -> EXTEND
 6: 20:50:25.528 -> DROP
 7: 20:50:25.532 <- PADDING_NEGOTIATED
 8: 20:50:25.532 <- DROP
 9: 20:50:25.537 -> DROP
 10: 20:50:25.545 -> DROP
 11: 20:50:25.552 -> DROP
 12: 20:50:25.553 <- DROP
 13: 20:50:25.554 <- EXTENDED
 14: 20:50:25.555 -> INTRODUCE1
 15: 20:50:25.556 <- DROP
 16: 20:50:25.556 <- DROP
 17: 20:50:25.561 -> DROP
 18: 20:50:25.565 -> DROP
 19: 20:50:25.569 -> DROP
 20: 20:50:25.573 -> DROP
 21: 20:50:25.578 <- DROP
 22: 20:50:25.578 <- DROP
 23: 20:50:25.584 -> DROP
 24: 20:50:25.592 -> DROP
 25: 20:50:25.597 -> DROP
 26: 20:50:25.601 <- DROP
 27: 20:50:25.601 <- DROP
 28: 20:50:25.602 <- DROP
 29: 20:50:25.625 <- DROP
 30: 20:50:25.625 <- DROP
 31: 20:50:25.626 <- DROP
 32: 20:50:25.626 <- INTRODUCE_ACK
 }}}
 and here is a rendezous circuit:
 {{{
 RP circuit 8 was created at 20:49:51.978
 Relay cells:
 0: 20:49:51.986 -> EXTEND2
 1: 20:49:52.116 <- EXTENDED2
 2: 20:49:52.117 -> EXTEND2
 3: 20:49:52.162 <- EXTENDED2
 4: 20:50:25.519 -> PADDING_NEGOTIATE
 5: 20:50:25.519 -> ESTABLISH_RENDEZVOUS
 6: 20:50:25.525 -> DROP
 7: 20:50:25.532 <- PADDING_NEGOTIATED
 8: 20:50:25.535 -> DROP
 9: 20:50:25.540 -> DROP
 10: 20:50:25.545 -> DROP
 11: 20:50:25.552 -> DROP
 12: 20:50:25.553 <- RENDEZVOUS_ESTABLISHED
 13: 20:50:25.554 <- DROP
 14: 20:50:25.555 <- DROP
 15: 20:50:25.560 -> DROP
 16: 20:50:25.564 -> DROP
 17: 20:50:25.569 -> DROP
 18: 20:50:25.578 <- DROP
 19: 20:50:25.578 <- DROP
 20: 20:50:25.601 <- DROP
 21: 20:50:25.601 <- DROP
 22: 20:50:25.601 <- DROP
 23: 20:50:25.625 <- DROP
 24: 20:50:25.625 <- DROP
 25: 20:50:25.625 <- DROP
 26: 20:50:25.626 <- DROP
 27: 20:50:25.635 <- DROP
 28: 20:50:25.677 <- DROP
 29: 20:50:25.677 <- DROP
 30: 20:50:25.681 <- DROP
 31: 20:50:25.704 <- RENDEZVOUS2
 32: 20:50:25.705 -> BEGIN
 33: 20:50:25.749 <- CONNECTED
 34: 20:50:25.837 -> DATA
 35: 20:50:26.753 -> DATA
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28634#comment:11>
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