I'd like to thank the many people who responded to my previous posting regarding SRP; there were too many messages for me to reply personally to everyone. I've compiled a brief digest of the messages I received, and I'll make it available to anyone who asks. If someone doesn't want their message included the digest, please let me know. Here's an anonymous synopsis of the replies I received: - There is an SRP mailing list, and someone who uses SRP said the Stanford people have been very responsive and helpful. Also, there's lots of info here: http://jafar.stanford.edu/srp/doc.html - Although Stanford's implementation only speaks about being free for "non-commercial use", their web page says the SRP technology "is based entirely on arithmetic and hashing, both of which can be done with freely-available code and algorithms. Thus, entirely free implementations of SRP can and have been written." - Someone said he was unable to find a BSD version. Someone else said he got it working on BSD, but with a minor "protocol problem". - Someone said work is being done on SRP-secured IMAP/POP implmentations. - Several people said that although the password exchange is secure, the actual sessions are unencrypted. If this is true, it's a serious deficiency of the protocols. However, the Stanford web page says: "SRP exchanges a session key in the process of authentication. This key can be used to encrypt the user's login session and protect it from both snooping and malicious active attack." - And, lastly, although the responses were generally enthusiastic, one person made this troublesome statement: "The Stanford campus as a whole does not use SRP. It has been considered and rejected as being largely untried (particularly within the crypto community) and having no obvious advantages over modern Kerberos in our environment. The security claims made by the grad students who invented the protocol have come under considerable fire by the sci.crypt community, and the methods by which they have attempted to prove the superiority of their solution have left something to be desired." And now for my personal opinions... :-) I've heard many people make statements which basically say "the general internet community is stupid and lazy for not adopting secure protocols, since many options exist and crypto technology is a tried&true theory." I'll state up front that I'm a novice when it comes to security, but it seems that none of the existing secure protocols is suitable as a "standard" for general acceptance. Each fails to meet one of the following apparently obvious basic requirements: - The technology should be freely available, both for commercial use and for GPL products. Preferably, not subject to US export regulations (e.g. it's developed outside of the US). - The protocols should provide secure client authentication, and optional server authentication, but without cumbersome keys or ticket servers to coordinate: A user should be able to walk into an an aribtrary computer lab and login with a username and password. Smartcards or floppy disks with key files should be strictly optional. :-) - The system should support all the basic modern advances in cryptography; it should be safe against packet sniffing, man-in-the-middle attacks, replay attacks, dictionary attacks, etc. The server should never get enough information from the user to reconstruct the user's password. - It should be easy to retrofit existing protocols. At the very least, there should be a standard implementation in portable library form. Converting a TCP service should be possible with a simple wrapper (like what sslwrap does). It seems like all the technology is there, but it's just a matter of someone putting the pieces together, drafting some RFC's, and releasing a library. SRP seems to come really close, and might actually be the sought solution if the claims on their web pages are true. Unfortunately, that last person's statement casts some doubt on this. Perhaps there already exists some ideal solution, and I've just overlooked it? If so, I would happily adopt it on my network and volunteer to help with retrofitting support for mail/www/telnet/ftp applications. :-) Pete Gonzalez Jefferson Systems gonzat_private
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 14:26:58 PDT