Blog about lib.ipsec implementation details

[eugeneia]

We should write a blog post that covers lib.ipsec internals in depth, specifically the cipher and ESP implementations. Hopefully, this will attract experienced eyes that will spot errors in our implementation, and maybe even someone who would like to implement an additional cipher using DynASM Lua mode.

[eugeneia]

See “Notes on implementing IPsec ESP for Snabb” http://mr.gy/blog/snabb-esp.html