Yang What do you mean by "mandatory to achieve".
What 33.320 says is that IPsec is mandatory to implement in HW, but optional to use. Furthermore, my interpretation is that timing packets are explicitly not covered, since they mention which types of packets should be protected, and none of the types mentioned describe timing packets. I have a question for you. Were we to use NTP with Autokey and thus provide strong proventication, would you see any benefit to using IPsec ? Do you agree that there is a drawback to its use ? Y(J)S -----Original Message----- From: Cui Yang [mailto:[email protected]] Sent: Thursday, March 15, 2012 05:30 To: Yaakov Stein Cc: [email protected]; Danny Mayer Subject: Re: [TICTOC] Please Comment on Practical Solutions for Encrypted Synchronization Protocol Hi, Yaakov, Thanks for your comments. Please find my answer in the following. The IPsec tunnel functionality in backhaul link between femto and SeGW are mandatory to achieve by 3GPP Technical Specification TS.33.320 http://www.3gpp.org/ftp/specs/html-info/33320.htm -4.3.1 Backhaul link -4.4.5 Requirements on Backhaul Link -7.4 IPsec Tunnel Establishment -etc. This requirement is originated from the typical use case of home based wireless base station (Femto), where the backhaul cable connection is commonly leased by telecom operator and through insecure networks, not belonging to operator’s own network. Since the regulation and laws on information security and privacy are strict in many countries, vendors are requested to set up this IPsec tunnel functionality to avoid the risk of information or privacy leakage. The contents encrypted in IPsec tunnel include not only data plane, but also control plane, where the former carries the customer’s data and voice, and the latter carries sensitive information, such as the secret keys for air interface encryption. For most of operators and vendors, it is considered necessary and responsible to protect customers’ privacy and communication security, where the best way known is IPsec tunnel. Best regards, Yang ================== Yang Cui, Ph.D. Huawei Technologies [email protected] > -----邮件原件----- > 发件人: Yaakov Stein [mailto:[email protected]] > 发送时间: 2012年3月15日 2:36 > 收件人: Cui Yang > 抄送: [email protected]; Danny Mayer > 主题: RE: [TICTOC] Please Comment on Practical Solutions for Encrypted > Synchronization Protocol > > Yang > > Yes, I fully appreciate the scenario you are discussing, > where ALL packets MUST be encrypted. > > I am just questioning whether such a scenario is really mandated by any > standard (I believe it is not), > in which case one can simply NOT encrypt the timing packets (even if you > choose to encrypt the other packets). > > Y(J)S > > -----Original Message----- > From: Cui Yang [mailto:[email protected]] > Sent: Tuesday, March 13, 2012 04:51 > To: Yaakov Stein; Danny Mayer > Cc: [email protected] > Subject: Re: [TICTOC] Please Comment on Practical Solutions for Encrypted > Synchronization Protocol > > Hi, Yaakov, > > Maybe my unclear description in the draft causes some confusion. Sorry for > that. > In the second motivation, we didn’t try to argue there is a scenario where > timing packets must be encrypted. > In contrast, we try to discuss the conditions where timing packets are > transported in an insecure network and there are already IPsec ESP tunnel > provided. > When we try to transport the timing packets in a secure way, we can reuse > the existing IPsec ESP tunnel even though the timing packets may not be > confidential itself (But integrity protection is necessary, anyway). > > Best regards, > Yang > ================== > Yang Cui, Ph.D. > Huawei Technologies > [email protected] > > > -----邮件原件----- > > 发件人: Yaakov Stein [mailto:[email protected]] > > 发送时间: 2012年3月13日 0:47 > > 收件人: Cui Yang; Danny Mayer > > 抄送: [email protected] > > 主题: RE: [TICTOC] Please Comment on Practical Solutions for Encrypted > > Synchronization Protocol > > > > Yang > > > > I fully understand your motivation (actually the 2nd motivation in your > draft) > > to handle cases where encryption of ALL packets is mandatory, including > > timing ones. > > > > However, I am not sure that TS 33.320 really mandates encryption of timing > > packets. > > > > First, 33.320 clearly states that while implementation of IPsec is > > mandatory, > > usage is optional and based on operator policy > > (with the possible exception of direct links between H(e)NBs, but these > links > > are optional too). > > If IPsec is not used, then a lower layer mechanism can be used > > (w/o any specification of what exactly this lower layer mechanism needs to > > do), > > a method assumedly running in HW and adding almost no delay and > > absolutely no delay variation. > > > > Second, even if the operator decides to use IPsec, then the standard states > > "All signalling, user, and management plane traffic over the interface > > between H(e)NB and SeGW shall be sent through an IPsec ESP tunnel". > > I think we can make the case that timing is neither signaling, nor user, nor > > management traffic, > > and thus exempt from the IPsec requirement. > > Perhaps we should send 3GPP a liaison to that effect, and get an explicit > > waiver. > > > > So, we are left with no use case mandating encrypting of timing packets, > > and the problem goes away. > > > > Y(J)S > > > > > > -----Original Message----- > > From: [email protected] [mailto:[email protected]] On Behalf > Of > > Cui Yang > > Sent: Thursday, March 08, 2012 03:44 > > To: Danny Mayer > > Cc: [email protected] > > Subject: Re: [TICTOC] Please Comment on Practical Solutions for Encrypted > > Synchronization Protocol > > > > Danny, > > > > Thanks for your comments. I will respond inline. > > > > > -----邮件原件----- > > > 发件人: Danny Mayer [mailto:[email protected]] > > > 发送时间: 2012年3月7日 20:56 > > > 收件人: Cui Yang > > > 抄送: [email protected] > > > 主题: Re: [TICTOC] Please Comment on Practical Solutions for Encrypted > > > Synchronization Protocol > > > > > > I have already said this before and I will repeat this for the purposes > > > of feedback. > > > > > > Time packets do not need to be encrypted as not only do they not > contain > > > anything secret, even if you knew the contents they are useless anytime > > > after the packet has been delivered. > > > > [Cui Yang] I will repeat our motivation. > > According to globally used 3GPP standard, there is a need for establish > IPsec > > ESP tunnel for small home base station connecting to Security GW or other > > core network devices. > > There have existed such a great number of IPsec ESP tunnels in the > > underlying use case. > > For meeting the least security requirement, it is needed to set up IPsec AH > or > > IPsec ESP-NULL for the integrity protection. > > Then it will increase the security cost. > > > > If there is a simple and practical solution for this problem, then why not > > let > it > > be clarified? > > So that, many engineers and customers can benefit from single IPsec > tunnel > > protection each user, which saves the cost for both. > > > > > You do yourself a disfavor in encrypting something that is not worth > > > encrypting. It takes processing overhead, increases packet size, and > > > there is no gain in doing so. You need to justify encrypting something > > > > [Cui Yang] I am not doing myself a disfavor, but going to provide a solution > for > > the practical and technical problem. > > Integrity protection takes overhead, as well. > > In case confidentiality is mandatory, is it a good idea to protect integrity > > separately? > > What we need to do, is to investigate and reduce the cost as small as > possible > > first, and see whether it is acceptable or not. > > That is our motivation of the new draft. > > > > > and please don't say that it is because some other document says to > > > encrypt everything. I want to know what is the benefit from doing so, > > > > [Cui Yang] I just answered your previous email providing the referred > section > > and document as you required, yesterday. > > > > > what are the risks in not doing so and what is the cost of doing so, > > > particularly in loss of accuracy, increased error budget, etc. > > > > [Cui Yang] That is our new draft trying to explain, please check it before > > posting your opinion. > > > > > The whole thing is a bad idea from what I can tell. > > > > > > Danny > > > > > > > Thanks, > > Yang > > > > > > > On 3/6/2012 10:35 PM, Cui Yang wrote: > > > > Hi, all, > > > > > > > > > > > > > > > > I have posted a new draft that discusses the practical solutions for > > > > encrypted synchronization protocols. > > > > > > > > > > > > > > > > Since we have discussed a lot on this problem, and the security > > > > requirement of synchronization also noted that confidentiality may > need > > > > protection, especially in case that the confidentiality protection is > > > > mandatory. Synchronization should be available when the traffic is > > > > encrypted. The influences by the encryption are explained, and several > > > > possible solutions have been discussed. > > > > > > > > The URL is below, please review and comment. > > > > > > > > > > > > > > > > Title : Practical solutions for encrypted synchronization > > protocol > > > > > > > > Author(s) : Y. Cui, > > > > > > > > M. Bhatia, > > > > > > > > D. Zhang > > > > > > > > Filename : draft-cui-tictoc-encrypted-synchronization-00.txt > > > > > > > > Pages : 10 > > > > > > > > Date : Mar. 1, 2012 > > > > > > > > This informational document analyzes the accuracy issues with time > > > > > > > > synchronization protocols when time synchronization packets are > > > > > > > > encrypted during transmission. In addition, several candidate > > > > > > > > solutions on such issues are introduced. > > > > > > > > > > > > > > > > A URL for this Internet-Draft is: > > > > > > > > > > http://datatracker.ietf.org/doc/draft-cui-tictoc-encrypted-synchronization > > > > > > > > > > > > > > > > Thanks, > > > > > > > > Yang > > > > > > > > ================== > > > > > > > > Yang Cui, Ph.D. > > > > > > > > Huawei Technologies > > > > > > > > [email protected] > > _______________________________________________ > > TICTOC mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/tictoc _______________________________________________ TICTOC mailing list [email protected] https://www.ietf.org/mailman/listinfo/tictoc
