Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-26 Thread Jeffrey Goldberg
On May 25, 2009, at 2:00 PM, Roland Smith wrote: You could use the -S option and specify a constant salt. It might make the encrypted materials easier to break, though. You can generate a random salt with openssl as well: Or you can use the -nosalt option. But as explained in

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-26 Thread Roland Smith
On Tue, May 26, 2009 at 09:31:25AM -0500, Jeffrey Goldberg wrote: On May 25, 2009, at 2:00 PM, Roland Smith wrote: You could use the -S option and specify a constant salt. It might make the encrypted materials easier to break, though. You can generate a random salt with openssl as well:

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-26 Thread RW
On Tue, 26 May 2009 19:02:10 +0200 Roland Smith rsm...@xs4all.nl wrote: Or if you have the case of a 'known-plaintext' attack. It happens more often than you would think: [http://en.wikipedia.org/wiki/Known-plaintext_attack] Note that using a random salt would be a good protection against

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-25 Thread RW
On Sun, 24 May 2009 22:57:35 -0700 Kelly Jones kelly.terry.jo...@gmail.com wrote: and was surprised that doing this to identical files yielded different results. I then realized openssl enc randomly(?) chooses a salt if you don't supply one. I want my backups encrypted, but I also want

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-25 Thread Roland Smith
On Sun, May 24, 2009 at 10:57:35PM -0700, Kelly Jones wrote: Are there any secure openssl symmetric encryption routines that *don't* use a salt? Is it secure to use a random-but-fixed salt (openssl enc -S salt)? man enc says This option [-salt] should ALWAYS be used [...] Reason I ask:

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-25 Thread RW
On Mon, 25 May 2009 21:00:39 +0200 Roland Smith rsm...@xs4all.nl wrote: Or you can use the -nosalt option. But as explained in [http://www.openssl.org/docs/apps/enc.html], using a random salt by default is a design decision because: Without the -salt option it is possible to perform

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-25 Thread Roland Smith
On Mon, May 25, 2009 at 10:06:01PM +0100, RW wrote: On Mon, 25 May 2009 21:00:39 +0200 Roland Smith rsm...@xs4all.nl wrote: Or you can use the -nosalt option. But as explained in [http://www.openssl.org/docs/apps/enc.html], using a random salt by default is a design decision because:

Re: Secure unsalted or fixed salt symmetric encryption?

2009-05-25 Thread RW
On Mon, 25 May 2009 23:52:05 +0200 Roland Smith rsm...@xs4all.nl wrote: On Mon, May 25, 2009 at 10:06:01PM +0100, RW wrote: On Mon, 25 May 2009 21:00:39 +0200 Roland Smith rsm...@xs4all.nl wrote: Or you can use the -nosalt option. But as explained in