I’ll agree that perhaps the “absolutely not” is not quite right. There are certainly some uses for a simpler solution, but I would still say it cannot only be encryption at the broker. This would leave many use cases for at-rest encryption out of the loop (most auditing cases for SOX, PCI, HIPAA, and other PII standards). Yes, it does add external overhead that must be managed, but it’s just the nature of the beast. We can’t solve all of the external infrastructure needed for this, but we can make it easier to use for consumers and producers by adding metadata.
There’s no need for unchanging encryption, and that’s specifically why I want to see a message envelope that will help consumers determine the encryption uses for a particular message. You can definitely still expire keys, you just have to keep the expired keys around as long as the encrypted data stays around, and your endpoints need to know when they are decrypting data with an expired key (you might want to throw up a warning, or do something else to let the users know that it’s happening). And as someone else mentioned, there are solutions for encrypting data for multiple consumers. You can encrypt the data with an OTP, and then multiply encrypt the OTP once for each consumer and store those encrypted strings in the envelope. -Todd On 6/7/14, 12:25 PM, "Rob Withers" <robert.w.with...@gmail.com> wrote: >At one level this makes sense to me to externalize the security issue >to producers and consumers. On consideration I realized that this >adds a lot of coordination requirements to the app layer across teams >or even companies. Another issue I feel is that you want a specific >unchanging encryption for the data and the clients (producers/ >consumers) will need to be able to decode frozen data. If certs are >used they cannot expire. Also, different clients would need to use >the same cert. > >So, you statement that it should ABSOLUTELY not include internal >encryption rings seems misplaced. There are some customers of kafka >that would opt to encrypt the on-disk data and key management is a >significant issue. This is best handled internally, with key >management stored in either ZK or in a topic. Truly, perhaps >annealing Hadoop/HBASE as a metadata store seems applicable. > >Thanks, another 2 cents, >Rob > >On Jun 6, 2014, at 12:15 PM, Todd Palino wrote: > >> Yes, I realized last night that I needed to be clearer in what I was >> saying. Encryption should ABSOLUTELY not be handled server-side. I >> think >> it¹s a good idea to enable use of it in the consumer/producer, but >> doing >> it server side will not solve many use cases for needing encryption >> because the server then has access to all the keys. You could say that >> this eliminates the need for TLS, but TLS is pretty low-hanging >> fruit, and >> there¹s definitely a need for encryption of the traffic across the >> network >> even if you don¹t need at-rest encryption as well. >> >> And as you mentioned, something needs to be done about key management. >> Storing information with the message about which key(s) was used is >> a good >> idea, because it allows you to know when a producer has switched keys. >> There are definitely some alternative solutions to that as well. But >> storing the keys in the broker, Zookeeper, or other systems like >> that are >> not. There needs to be a system used where the keys are only >> available to >> the producers and consumers that need them, and they only get access >> to >> the appropriate part of the key pair. Even as the guy running Kafka >> and >> Zookeeper, I should not have access to the keys being used, and if >> data is >> encrypted I should not be able to see the cleartext. >> >> And even if we decide not to put anything about at-rest encryption >> in the >> consumer/producer clients directly, and leave it for an exercise above >> that level (you have to pass the ciphertext as the message to the >> client), >> I still think there is a good case for implementing a message envelope >> that can store the information about which key was used, and other >> pertinent metadata, and have the ability for special applications like >> mirror maker to be able to preserve it across clusters. This still >> helps >> to enable the use of encryption and other features (like auditing) >> even if >> we decide it¹s too large a scope to fully implement. >> >> -Todd >> >> On 6/6/14, 10:51 AM, "Pradeep Gollakota" <pradeep...@gmail.com> wrote: >> >>> I'm actually not convinced that encryption needs to be handled >>> server side >>> in Kafka. I think the best solution for encryption is to handle it >>> producer/consumer side just like compression. This will offload key >>> management to the users and we'll still be able to leverage the >>> sendfile >>> optimization for better performance. >>> >>> >>> On Fri, Jun 6, 2014 at 10:48 AM, Rob Withers >>><robert.w.with...@gmail.com >>> > >>> wrote: >>> >>>> On consideration, if we have 3 different access groups (1 for >>>> production >>>> WRITE and 2 consumers) they all need to decode the same encryption >>>> and >>>> so >>>> all need the same public/private key....certs won't work, unless you >>>> write >>>> a CertAuthority to build multiple certs with the same keys. Better >>>> seems >>>> to not use certs and wrap the encryption specification with an ACL >>>> capabilities for each group of access. >>>> >>>> >>>> On Jun 6, 2014, at 11:43 AM, Rob Withers wrote: >>>> >>>> This is quite interesting to me and it is an excelent opportunity to >>>>> promote a slightly different security scheme. Object- >>>>> capabilities are >>>>> perfect for online security and would use ACL style >>>>> authentication to >>>>> gain >>>>> capabilities filtered to those allowed resources for allow actions >>>>> (READ/WRITE/DELETE/LIST/SCAN). Erights.org has the >>>>> quitenscential (??) >>>>> object capabilities model and capnproto is impleemting this for C+ >>>>> +. I >>>>> have a java implementation at http://github.com/pauwau/pauwau but >>>>> the >>>>> master is broken. 0.2 works, basically. B asically a TLS >>>>> connection >>>>> with >>>>> no certificate server, it is peer to peer. It has some advanced >>>>> features, >>>>> but the lining of capabilities with authorization so that you can >>>>> only >>>>> invoke correct services is extended to the secure user. >>>>> >>>>> Regarding non-repudiation, on disk, why not prepend a CRC? >>>>> >>>>> Regarding on-disk encryption, multiple users/groups may need to >>>>> access, >>>>> with different capabilities. Sounds like zookeeper needs to >>>>> store a >>>>> cert >>>>> for each class of access so that a group member can access the >>>>> decrypted >>>>> data from disk. Use cert-based async decryption. The only isue is >>>>> storing >>>>> the private key in zookeeper. Perhaps some hash magic could be >>>>> used. >>>>> >>>>> Thanks for kafka, >>>>> Rob >>>>> >>>>> On Jun 5, 2014, at 3:01 PM, Jay Kreps wrote: >>>>> >>>>> Hey Joe, >>>>>> >>>>>> I don't really understand the sections you added to the wiki. >>>>>> Can you >>>>>> clarify them? >>>>>> >>>>>> Is non-repudiation what SASL would call integrity checks? If so >>>>>> don't >>>>>> SSL >>>>>> and and many of the SASL schemes already support this as well as >>>>>> on-the-wire encryption? >>>>>> >>>>>> Or are you proposing an on-disk encryption scheme? Is this >>>>>> actually >>>>>> needed? >>>>>> Isn't a on-the-wire encryption when combined with mutual >>>>>> authentication >>>>>> and >>>>>> permissions sufficient for most uses? >>>>>> >>>>>> On-disk encryption seems unnecessary because if an attacker can >>>>>> get >>>>>> root >>>>>> on >>>>>> the kafka boxes it can potentially modify Kafka to do anything >>>>>> he or >>>>>> she >>>>>> wants with data. So this seems to break any security model. >>>>>> >>>>>> I understand the problem of a large organization not really >>>>>> having a >>>>>> trusted network and wanting to secure data transfer and limit and >>>>>> audit >>>>>> data access. The uses for these other things I don't totally >>>>>> understand. >>>>>> >>>>>> Also it would be worth understanding the state of other >>>>>> messaging and >>>>>> storage systems (Hadoop, dbs, etc). What features do they >>>>>> support. I >>>>>> think >>>>>> there is a sense in which you don't have to run faster than the >>>>>> bear, >>>>>> but >>>>>> only faster then your friends. :-) >>>>>> >>>>>> -Jay >>>>>> >>>>>> >>>>>> On Wed, Jun 4, 2014 at 5:57 PM, Joe Stein <joe.st...@stealth.ly> >>>>>> wrote: >>>>>> >>>>>> I like the idea of working on the spec and prioritizing. I will >>>>>> update >>>>>>> the >>>>>>> wiki. >>>>>>> >>>>>>> - Joestein >>>>>>> >>>>>>> >>>>>>> On Wed, Jun 4, 2014 at 1:11 PM, Jay Kreps <jay.kr...@gmail.com> >>>>>>> wrote: >>>>>>> >>>>>>> Hey Joe, >>>>>>>> >>>>>>>> Thanks for kicking this discussion off! I totally agree that for >>>>>>>> >>>>>>> something >>>>>>> >>>>>>>> that acts as a central message broker security is critical >>>>>>>> feature. >>>>>>>> I >>>>>>>> >>>>>>> think >>>>>>> >>>>>>>> a number of people have been interested in this topic and >>>>>>>> several >>>>>>>> people >>>>>>>> have put effort into special purpose security efforts. >>>>>>>> >>>>>>>> Since most the LinkedIn folks are working on the consumer >>>>>>>> right now >>>>>>>> I >>>>>>>> >>>>>>> think >>>>>>> >>>>>>>> this would be a great project for any other interested people to >>>>>>>> take >>>>>>>> on. >>>>>>>> There are some challenges in doing these things distributed >>>>>>>> but it >>>>>>>> can >>>>>>>> >>>>>>> also >>>>>>> >>>>>>>> be a lot of fun. >>>>>>>> >>>>>>>> I think a good first step would be to get a written plan we >>>>>>>> can all >>>>>>>> agree >>>>>>>> on for how things should work. Then we can break things down >>>>>>>> into >>>>>>>> chunks >>>>>>>> that can be done independently while still aiming at a good end >>>>>>>> state. >>>>>>>> >>>>>>>> I had tried to write up some notes that summarized at least the >>>>>>>> thoughts >>>>>>>> >>>>>>> I >>>>>>> >>>>>>>> had had on security: >>>>>>>> https://cwiki.apache.org/confluence/display/KAFKA/Security >>>>>>>> >>>>>>>> What do you think of that? >>>>>>>> >>>>>>>> One assumption I had (which may be incorrect) is that although >>>>>>>> we >>>>>>>> want >>>>>>>> >>>>>>> all >>>>>>> >>>>>>>> the things in your list, the two most pressing would be >>>>>>>> authentication >>>>>>>> >>>>>>> and >>>>>>> >>>>>>>> authorization, and that was all that write up covered. You >>>>>>>> have more >>>>>>>> experience in this domain, so I wonder how you would prioritize? >>>>>>>> >>>>>>>> Those notes are really sketchy, so I think the first goal I >>>>>>>> would >>>>>>>> have >>>>>>>> would be to get to a real spec we can all agree on and >>>>>>>> discuss. A >>>>>>>> lot >>>>>>>> of >>>>>>>> the security stuff has a high human interaction element and >>>>>>>> needs to >>>>>>>> work >>>>>>>> in pretty different domains and different companies so getting >>>>>>>> this >>>>>>>> kind >>>>>>>> >>>>>>> of >>>>>>> >>>>>>>> review is important. >>>>>>>> >>>>>>>> -Jay >>>>>>>> >>>>>>>> >>>>>>>> On Tue, Jun 3, 2014 at 12:57 PM, Joe Stein >>>>>>>> <joe.st...@stealth.ly> >>>>>>>> wrote: >>>>>>>> >>>>>>>> Hi,I wanted to re-ignite the discussion around Apache Kafka >>>>>>>> Security. >>>>>>>>> >>>>>>>> This >>>>>>>> >>>>>>>>> is a huge bottleneck (non-starter in some cases) for a lot of >>>>>>>>> >>>>>>>> organizations >>>>>>>> >>>>>>>>> (due to regulatory, compliance and other requirements). Below >>>>>>>>> are >>>>>>>>> my >>>>>>>>> suggestions for specific changes in Kafka to accommodate >>>>>>>>> security >>>>>>>>> requirements. This comes from what folks are doing "in the >>>>>>>>> wild" >>>>>>>>> to >>>>>>>>> workaround and implement security with Kafka as it is today and >>>>>>>>> also >>>>>>>>> >>>>>>>> what I >>>>>>>> >>>>>>>>> have discovered from organizations about their blockers. It >>>>>>>>> also >>>>>>>>> picks >>>>>>>>> >>>>>>>> up >>>>>>> >>>>>>>> from the wiki (which I should have time to update later in the >>>>>>>> week >>>>>>>>> >>>>>>>> based >>>>>>> >>>>>>>> on the below and feedback from the thread). >>>>>>>>> >>>>>>>>> 1) Transport Layer Security (i.e. SSL) >>>>>>>>> >>>>>>>>> This also includes client authentication in addition to in- >>>>>>>>> transit >>>>>>>>> >>>>>>>> security >>>>>>>> >>>>>>>>> layer. This work has been picked up here >>>>>>>>> https://issues.apache.org/jira/browse/KAFKA-1477 and do >>>>>>>>> appreciate >>>>>>>>> any >>>>>>>>> thoughts, comments, feedback, tomatoes, whatever for this >>>>>>>>> patch. >>>>>>>>> It >>>>>>>>> >>>>>>>> is a >>>>>>> >>>>>>>> pickup from the fork of the work first done here >>>>>>>>> https://github.com/relango/kafka/tree/kafka_security. >>>>>>>>> >>>>>>>>> 2) Data encryption at rest. >>>>>>>>> >>>>>>>>> This is very important and something that can be facilitated >>>>>>>>> within >>>>>>>>> the >>>>>>>>> wire protocol. It requires an additional map data structure >>>>>>>>> for the >>>>>>>>> "encrypted [data encryption key]". With this map (either in >>>>>>>>> your >>>>>>>>> object >>>>>>>>> >>>>>>>> or >>>>>>>> >>>>>>>>> in the wire protocol) you can store the dynamically generated >>>>>>>>> symmetric >>>>>>>>> >>>>>>>> key >>>>>>>> >>>>>>>>> (for each message) and then encrypt the data using that >>>>>>>>> dynamically >>>>>>>>> generated key. You then encrypt the encryption key using each >>>>>>>>> public >>>>>>>>> >>>>>>>> key >>>>>>> >>>>>>>> for whom is expected to be able to decrypt the encryption key to >>>>>>>> then >>>>>>>>> decrypt the message. For each public key encrypted symmetric >>>>>>>>> key >>>>>>>>> >>>>>>>> (which >>>>>>> >>>>>>>> is >>>>>>>> >>>>>>>>> now the "encrypted [data encryption key]" along with which >>>>>>>>> public >>>>>>>>> key >>>>>>>>> >>>>>>>> it >>>>>>> >>>>>>>> was encrypted with for (so a map of [publicKey] = >>>>>>>>> encryptedDataEncryptionKey) as a chain. Other patterns can be >>>>>>>>> >>>>>>>> implemented >>>>>>>> >>>>>>>>> but this is a pretty standard digital enveloping [0] pattern >>>>>>>>> with >>>>>>>>> only >>>>>>>>> >>>>>>>> 1 >>>>>>> >>>>>>>> field added. Other patterns should be able to use that field >>>>>>>> to-do >>>>>>>>> >>>>>>>> their >>>>>>> >>>>>>>> implementation too. >>>>>>>>> >>>>>>>>> 3) Non-repudiation and long term non-repudiation. >>>>>>>>> >>>>>>>>> Non-repudiation is proving data hasn't changed. This is >>>>>>>>> often (if >>>>>>>>> not >>>>>>>>> always) done with x509 public certificates (chained to a >>>>>>>>> certificate >>>>>>>>> authority). >>>>>>>>> >>>>>>>>> Long term non-repudiation is what happens when the >>>>>>>>> certificates of >>>>>>>>> the >>>>>>>>> certificate authority are expired (or revoked) and everything >>>>>>>>> ever >>>>>>>>> >>>>>>>> signed >>>>>>> >>>>>>>> (ever) with that certificate's public key then becomes "no >>>>>>>> longer >>>>>>>>> >>>>>>>> provable >>>>>>>> >>>>>>>>> as ever being authentic". That is where RFC3126 [1] and >>>>>>>>> RFC3161 >>>>>>>>> [2] >>>>>>>>> >>>>>>>> come >>>>>>> >>>>>>>> in (or worm drives [hardware], etc). >>>>>>>>> >>>>>>>>> For either (or both) of these it is an operation of the >>>>>>>>> encryptor >>>>>>>>> to >>>>>>>>> sign/hash the data (with or without third party trusted >>>>>>>>> timestap of >>>>>>>>> the >>>>>>>>> signing event) and encrypt that with their own private key and >>>>>>>>> >>>>>>>> distribute >>>>>>> >>>>>>>> the results (before and after encrypting if required) along with >>>>>>>> their >>>>>>>>> public key. This structure is a bit more complex but >>>>>>>>> feasible, it >>>>>>>>> is a >>>>>>>>> >>>>>>>> map >>>>>>>> >>>>>>>>> of digital signature formats and the chain of dig sig >>>>>>>>> attestations. >>>>>>>>> >>>>>>>> The >>>>>>> >>>>>>>> map's key being the method (i.e. CRC32, PKCS7 [3], XmlDigSig >>>>>>>> [4]) >>>>>>>> and >>>>>>>>> >>>>>>>> then >>>>>>>> >>>>>>>>> a list of map where that key is "purpose" of signature (what >>>>>>>>> your >>>>>>>>> >>>>>>>> attesting >>>>>>>> >>>>>>>>> too). As a sibling field to the list another field for "the >>>>>>>>> attester" >>>>>>>>> >>>>>>>> as >>>>>>> >>>>>>>> bytes (e.g. their PKCS12 [5] for the map of PKCS7 signatures). >>>>>>>>> >>>>>>>>> 4) Authorization >>>>>>>>> >>>>>>>>> We should have a policy of "404" for data, topics, partitions >>>>>>>>> (etc) if >>>>>>>>> authenticated connections do not have access. In "secure >>>>>>>>> mode" any >>>>>>>>> non >>>>>>>>> authenticated connections should get a "404" type message on >>>>>>>>> >>>>>>>> everything. >>>>>>> >>>>>>>> Knowing "something is there" is a security risk in many uses >>>>>>>> cases. >>>>>>>> So >>>>>>>>> >>>>>>>> if >>>>>>>> >>>>>>>>> you don't have access you don't even see it. Baking "that" >>>>>>>>> into >>>>>>>>> Kafka >>>>>>>>> along with some interface for entitlement (access management) >>>>>>>>> systems >>>>>>>>> (pretty standard) is all that I think needs to be done to the >>>>>>>>> core >>>>>>>>> >>>>>>>> project. >>>>>>>> >>>>>>>>> I want to tackle item later in the year after summer after the >>>>>>>>> other >>>>>>>>> >>>>>>>> three >>>>>>>> >>>>>>>>> are complete. >>>>>>>>> >>>>>>>>> I look forward to thoughts on this and anyone else interested >>>>>>>>> in >>>>>>>>> >>>>>>>> working >>>>>>> >>>>>>>> with us on these items. >>>>>>>>> >>>>>>>>> [0] >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> http://www.emc.com/emc-plus/rsa-labs/standards- >>>>>>> initiatives/what-is-a-digital-envelope.htm >>>>>>> >>>>>>>> [1] http://tools.ietf.org/html/rfc3126 >>>>>>>>> [2] http://tools.ietf.org/html/rfc3161 >>>>>>>>> [3] >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> http://www.emc.com/emc-plus/rsa-labs/standards-initiatives/pkcs-7- >>>>>>> cryptographic-message-syntax-standar.htm >>>>>>> >>>>>>>> [4] http://en.wikipedia.org/wiki/XML_Signature >>>>>>>>> [5] http://en.wikipedia.org/wiki/PKCS_12 >>>>>>>>> >>>>>>>>> /******************************************* >>>>>>>>> Joe Stein >>>>>>>>> Founder, Principal Consultant >>>>>>>>> Big Data Open Source Security LLC >>>>>>>>> http://www.stealth.ly >>>>>>>>> Twitter: @allthingshadoop >>>>>>>>><http://www.twitter.com/allthingshadoop >>>>>>>>> > >>>>>>>>> ********************************************/ >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>> >>>> >> >
