Re: [dhcwg] Fw:New Version Notification for draft-cui-dhc-dhcpv6-encryption-00.txt
神明達哉 <jinmei@wide.ad.jp> Mon, 13 July 2015 16:32 UTC
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Date: Mon, 13 Jul 2015 09:32:12 -0700
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From: 神明達哉 <jinmei@wide.ad.jp>
To: Lishan Li <lilishan9248@163.com>
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Subject: Re: [dhcwg] Fw:New Version Notification for draft-cui-dhc-dhcpv6-encryption-00.txt
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At Mon, 13 Jul 2015 15:54:55 +0800 (CST), "Lishan Li" <lilishan9248@163.com> wrote: > >- Especially if we use "Solution A", wouldn't it be better to use a > > symmetric key after authentication, rather than keep using > > public/private keys? For a client that may not matter much, but for > > a busy server the performance overhead difference might be > > substantial. > > [Lishan] I agree that the server's performance would be affected if keeping using public/private keys. But if we use symmetric key for encryption, the problem would be how to transmit the symmetric key securely. > How about firstly we use the asymmetric key mechanism to achieve the encrypted transmission of the symmetric key, and then encrypt DHCPv6 messages with the symmetric keys. That will be a usual practice to deal with this kind of concern. But I don't know if the performance concern is actually substantial or it's just an imaginary one; it was just part of my *random* thoughts. Some experiments may help before we even discuss this further. > >- And, to this end, would it be feasible to use a separate encryption > > mechanism such as DTLS rather than introducing a built-in mechanism > > for DHCP(v6)? (In case of DTLS we should at least consider how to > > handle multicast traffic, though). > > [Lishan] I have considered "DHCP over DTLS" in the initial thoughts / version. However, for the typical use case with relays, I am afraid that the relay would not recognize the 'secured' DHCP messages, so that may drop the DTLS messages. Do you think this concern is valid? Ah, okay. I see it will be very tricky (if not unsolvable). It would be helpful if you include this discussion in the draft. -- JINMEI, Tatuya