Re: Explicit measurability in the QUIC wire image (was Re: Packet number encryption)

[Mikkel Fahnøe Jørgensen <[e-mail]>]

> Sender exposes one bit per packet that can be observed by on-path
> devices. The bit is flipped for every 256 packets that the sender
> sends. Observer records the bit of each packet as they pass by.



This is a pretty cool idea, but it doesn't provide enough information to
protect the spin bit from reordering. This could be easily fixed by moving
to a two-bit spin, as Gorry (I think) suggested. Among other things in this
space, Piet's also looking into how much reordering information could be
extracted from a two-bit spin itself.



This idea can be taken further: You can modulate the signal so you use
multiple packets to encode a zero or a one for half the wave duration. For
example 1 could be encoded as 0101 over four packets and zero could be
encoded as 0011 over four packets.
If there is any reordering, it would show up as an unexpected value in the
pulse.