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Date: Sun, 11 Dec 2016 16:30:27 +0100
From: Andrew Lunn <andrew@lunn.ch>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: Re: Misalignment, MIPS, and ip_hdr(skb)->version
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> 3. Add 3 bytes of padding, set to zero, to the encrypted section just
> before the IP header, marked for future use.
> Pros: satisfies IETF mantras, can use those extra bits in the future
> for interesting protocol extensions for authenticated peers.
> Cons: lowers MTU, marginally more difficult to implement but still
> probably just one or two lines of code.

I'm not a crypto expert, but does this not give you a helping hand in
breaking the crypto? You know the plain text value of these bytes, and
where they are in the encrypted text.

      Andrew