On Thu, 1 Mar 2012, Jeffrey Walton wrote:

On Thu, Mar 1, 2012 at 10:27 PM, Steven Bellovin <[email protected]> wrote:
http://www.scmagazine.com.au/News/292189,nsa-builds-android-phone-for-top-secret-calls.aspx
makes for interesting reading.  I was particularly intrigued by this:

       Voice calls are encrypted twice in accordance with NSA policy,
       using IPSEC and SRTP, meaning a failure requires “two independent
       bad things to happen,” Salter said.

Margaret Salter is the head of the Information Assurance Directorate
of the NSA.
Interesting. I seem to recall that cascading ciphers is frowned upon
on sci.crypt. I wonder if this is mis-information....


Yes, I've had that beaten into my head from books/talks/posts forever now, but I never quite understood it.

If the end result of your ciphertext has headers or metadata that can be used for known-plaintext attack, then it makes sense, but if you are just feeding raw ciphertext into the next algorithm, it shouldn't be a danger... right ?
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