Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-03 Thread Ryan Lane
On Fri, Aug 2, 2013 at 7:23 PM, Anthony wikim...@inbox.org wrote: On Fri, Aug 2, 2013 at 10:07 PM, Anthony wikim...@inbox.org wrote: Anthony wrote: How much padding is already inherent in HTTPS? None, which is why Ryan's Google Maps fingerprinting example works. Citation

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-03 Thread Anthony
On Sat, Aug 3, 2013 at 4:19 AM, Ryan Lane rl...@wikimedia.org wrote: On Fri, Aug 2, 2013 at 7:23 PM, Anthony wikim...@inbox.org wrote: It seems that the ciphers which run in CBC mode, at least, are padded. Wikipedia currently seems to be set to use RC4 128. I'm not sure what, if any,

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-03 Thread Tyler Romeo
On Sat, Aug 3, 2013 at 4:19 AM, Ryan Lane rl...@wikimedia.org wrote: We're currently have RC4 and AES ciphers in our list, but have RC4 listed first and have a server preference list to combat BEAST. TLS 1.1/1.2 are enabled and I'll be adding the GCM ciphers to the beginning of the list

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread George Herbert
On Aug 1, 2013, at 10:07 PM, Ryan Lane rl...@wikimedia.org wrote: Also, our resources are delivered from a number of urls (upload, bits, text) making it easier to identify resources. Even with padding you can take the relative size of resources being delivered, and the order of those sizes

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
George William Herbert wrote: ... It would also not be much more effort or customer impact to pad to the next larger 1k size for a random large fraction of transmissions. Padding each transmission with a random number of bytes, up to say 50 or 100, might provide a greater defense against

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
On Fri, Aug 2, 2013 at 1:32 PM, James Salsman jsals...@gmail.com wrote: George William Herbert wrote: ... It would also not be much more effort or customer impact to pad to the next larger 1k size for a random large fraction of transmissions. Padding each transmission with a random

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Marc A. Pelletier
On 08/02/2013 01:32 PM, James Salsman wrote: Padding each transmission with a random number of bytes, up to say 50 or 100, might provide a greater defense against fingerprinting while saving massive amounts of bandwidth. It would slightly change the algorithm used to make the fingerprint, not

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
How much padding is already inherent in HTTPS? Does the protocol pad to the size of the blocks in the block cipher? Seems to me that any amount of padding is going to give little bang for the buck, at least without using some sort of pipelining. You could probably do quite a bit if you

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
Marc A. Pelletier wrote: ... A minor random increase of size in document wouldn't even slow down [fingerprinting.] That's absolutely false. The last time I measured the sizes of all 9,625 vital articles, there was only one at the median length of 30,356 bytes but four articles up to 50 bytes

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Matthew Flaschen
On 08/02/2013 05:06 PM, James Salsman wrote: Marc, I note that you have recommending not keeping the Perl CPAN modules up to date on Wikimedia Labs: http://www.mediawiki.org/w/index.php?title=Wikimedia_Labs/Tool_Labs/Needed_Toolserver_featuresdiff=678902oldid=678746 saying that out of date

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Marc A. Pelletier
On 08/02/2013 05:50 PM, Matthew Flaschen wrote: It seems from the context better tested meant something like people are using this in practice in real environments, not only automated testing. And, indeed, given the constraints and objectives of the Tool Labs (i.e.: no secrecy, all open source

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
... random padding without (at least) pipelining and placards *is* worthless to protect against traffic analysis No, that is not true, and http://www.ieee-security.org/TC/SP2012/papers/4681a332.pdf explains why. Padding makes it difficult but not impossible to distinguish between two HTTPS

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Marc A. Pelletier
On 08/02/2013 08:15 PM, James Salsman wrote: No, that is not true, and http://www.ieee-security.org/TC/SP2012/papers/4681a332.pdf explains why. Padding makes it difficult but not impossible to distinguish between two HTTPS destinations. 4,300,000 destinations is right out. ... have you

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
Marc A. Pelletier wrote: ... http://www.ieee-security.org/TC/SP2012/papers/4681a332.pdf ... have you actually /read/ that paper? Of course I have. Have you read the conclusions at the bottom right of page 344? What kind of an adversary trying to infer our readers' article selections is going to

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
Anthony wrote: How much padding is already inherent in HTTPS? None, which is why Ryan's Google Maps fingerprinting example works. Citation needed. ... Seems to me that any amount of padding is going to give little bang for the buck Again, can we please procure expert opinions

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
On Fri, Aug 2, 2013 at 10:07 PM, Anthony wikim...@inbox.org wrote: Anthony wrote: How much padding is already inherent in HTTPS? None, which is why Ryan's Google Maps fingerprinting example works. Citation needed. Also please address

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
please address https://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Padding Sure. As soon as someone creates http://en.wikipedia.org/wiki/Sunset_Shimmerso I can use an appropriate example. ___ Wikimedia-l mailing list

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread James Salsman
Anthony, padding in this context means adding null or random bytes to the end of encrypted TCP streams in order to obscure their true length. The process of adding padding is entirely independent of the choice of underlying cipher. In this case, however, we have been discussing perfect forward

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
On Fri, Aug 2, 2013 at 11:09 PM, James Salsman jsals...@gmail.com wrote: Anthony, padding in this context means adding null or random bytes to the end of encrypted TCP streams in order to obscure their true length. The process of adding padding is entirely independent of the choice of

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-02 Thread Anthony
On Fri, Aug 2, 2013 at 11:33 PM, Anthony wikim...@inbox.org wrote: AES and CBC, which would be a block cipher which pads to 128 or 256 bytes. I mean bits, of course. ___ Wikimedia-l mailing list Wikimedia-l@lists.wikimedia.org Unsubscribe:

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-01 Thread Ryan Lane
On Thu, Aug 1, 2013 at 1:33 PM, James Salsman jsals...@gmail.com wrote: With the NSA revelations over the past months, there has been some very questionable information starting to circulate suggesting that trying to implement perfect forward secrecy for https web traffic isn't worth the

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-01 Thread James Salsman
Ryan Lane wrote: ... Assuming traffic analysis can be used to determine your browsing habits as they are occurring (which is likely not terribly hard for Wikipedia) The Google Maps example you linked to works by building a huge database of the exact byte sizes of satellite image tiles. Are you

Re: [Wikimedia-l] Disinformation regarding perfect forward secrecy for HTTPS

2013-08-01 Thread Ryan Lane
On Thursday, August 1, 2013, James Salsman wrote: Ryan Lane wrote: ... Assuming traffic analysis can be used to determine your browsing habits as they are occurring (which is likely not terribly hard for Wikipedia) The Google Maps example you linked to works by building a huge database