Watermarking...
Hi all, I was wondering if any of you have some pointers on the security of watermarking. In particular I am interested in public-key or asymmetric watermarking algorithms. Also, do you know of any free-to-use (opensource/etc.) implementation that can be used for research-test purposes ? -- Best Regards, Massimiliano Pala --o Massimiliano Pala [OpenCA Project Manager] ope...@acm.org project.mana...@openca.org Dartmouth Computer Science Dept Home Phone: +1 (603) 369-9332 PKI/Trust Laboratory Work Phone: +1 (603) 646-8734 --o People who think they know everything are a great annoyance to those of us who do. -- Isaac Asimov - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: Watermarking...
[Moderator's note: Please no top posting. --Perry] Hello Sandy, all, basically what I need is a library that will allow me to check for a watermark into an image/video/etc. It could be different algorithms for different media type - my work is not related to the algorithms themselves. The important issues are: * the algorithm(s) should be based on public key (asymmetric) * my program should be able to verify that a watermark exists and has been generated with a private key corresponding to a specific public key * an attacker should not be able to add a watermark that my app would recognize as valid (ie., the verification would fail when using my app's public key if an attacker tries to substitute the watermark) * if the watermark is removed/altered/substituted I should be able to detect it * the watermark should be invisible Do you know if/where can I find some libraries that provides me with some implementation of one or more algorithms that satisfy my needs ? I know there are a lot of publications about these algorithms, but I need a usable (also if not perfect) implementation.. preferably written in C/C++ Cheers, Max On 04/20/2010 09:49 AM, Sandy Harris wrote: What are your threat model and goals for the watermarking? Some watermarks -- like the photographer's copyright notice across a web picture -- are designed to be extremely visible. The whole idea is that if anyone steals the photo, everyone will know. For other threats, you might want a watermark to be completely invisible, perhaps even undetectable without some sort of key. Does it need to be tamper-resistant or unremovable? -- Best Regards, Massimiliano Pala --o Massimiliano Pala [OpenCA Project Manager] ope...@acm.org project.mana...@openca.org Dartmouth Computer Science Dept Home Phone: +1 (603) 369-9332 PKI/Trust Laboratory Work Phone: +1 (603) 646-8734 --o People who think they know everything are a great annoyance to those of us who do. -- Isaac Asimov - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to majord...@metzdowd.com
Re: Quantum Cryptography
Victor Duchovni wrote: Quantum Cryptography or Quantum Computing (i.e. cryptanysis)? - Quantum Cryptography is fiction (strictly claims that it solves an applied problem are fiction, indisputably interesting Physics). I do not really agree on this statement. There are ongoing projects, that I know of, that are actually working on maximizing communication throughput (which is currently not very good) on encrypted channels and minimizing costs of involved equipment. AFAIK, one great advantage of quantum crypto is in the area of key-exchange when establishing a secure communication. I guess quantum crypto is definitely not fiction (Anyhow I do not know if it has already been used somewhere... ). Later, -- Best Regards, Massimiliano Pala --o Massimiliano Pala [OpenCA Project Manager][EMAIL PROTECTED] [EMAIL PROTECTED] Dartmouth Computer Science Dept Home Phone: +1 (603) 397-3883 PKI/Trust - Office 063Work Phone: +1 (603) 646-9179 --o smime.p7s Description: S/MIME Cryptographic Signature
Re: OT: SSL certificate chain problems
Hi, you should provide the whole chain starting from the CA that issued the server cert. Be careful, though, because you should *NOT* provide the root cert in the chain as well. Moreover you should use the: SSLCertificateChainFile not the SSLCACertificateFile (which is for client auth). Cheers, Max. Travis H. wrote: Hi, This is not really typical of the traffic on this list, hence the OT. I send it because I think this is one of the few places where I'll find some people with deep understanding of SSL certs. Recently I had an issue where Google checkout would not accept an SSL certificate because Apache didn't present the entire hierarchy, just the site certificate itself. The CA was Thawte. What Google said was that many browsers supply missing certs as needed, but apparently their software did not. The fix would seem to be easy; just put the right CA root cert in the SSLCACertFile directive. or point to the directory with SSLCACertPath. However, I've tried over and over with various root CA certs downloaded from Thawte, and with one intermediate CA cert, and various combinations thereof, but with no sucess. -- Best Regards, Massimiliano Pala --o Massimiliano Pala [OpenCA Project Manager][EMAIL PROTECTED] [EMAIL PROTECTED] Dartmouth Computer Science Dept Home Phone: +1 (603) 397-3883 PKI/Trust - Office 063Work Phone: +1 (603) 646-9179 --o smime.p7s Description: S/MIME Cryptographic Signature
Re: signing all outbound email
Jon Callas wrote: On 4 Sep 2006, at 4:13 AM, Travis H. wrote: Has anyone created hooks in MTAs so that they automagically [...] Go look at http://www.dkim.org/ for many more details. This approach is MTA-to-MTA... if you want something more MTA-to-MUA, then you can take a look at this: http://www.springerlink.com/content/qt219462521k1113/?p=0f0727071a8245b7b5774b729461322epi=0 Cheers, Max smime.p7s Description: S/MIME Cryptographic Signature
