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

[Mikkel Fahnøe Jørgensen <[e-mail]>]

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.


You can take it even further and add error correcting codes into the
sequence.

Or likewise, you could generate a known random sequence such as PI, or
perhaps simpler, an AES generated sequence.

It is easy to sync the signal by hashing bits from multiple packets and
therefore easy to detect any missing bits. If there is massive loss, a
binary search can be conducted to find the location of the surviving
packets. It sort of breaks down if every other packet is reordered but you
could still handle that with some consideration.

The signal could repeat with a period significantly larger that practical
RTT rather than running an infinite sequence.

Technically it would also make it possible to remove the packet number
entirely because the number can be estimated by end-points and trial
decrypted, but that would likely not be performance optimal.