[guardian-dev] The sound of an encrypted audio stream

[Hans-Christoph Steiner]

I could also see adaptive audio filters that fill in the vowel sounds based on
the same kind of algorithm as auto-complete typing.  It could use the timing
and spectrum of the audio events as one source of information for filling in
the rest.  A decent DSP math person spending a few months on that problem
could make some noticeable improvements.  That bar is not very high.

Lee, where is that sound file from?  Its pretty awesome.

.hc

On 07/23/2013 04:57 PM, Josh Steiner wrote:
> Whoa, that is way too recognizably human for comfort.  i could totally see
> with some training being able to understand that.
> 
> -j
> 
> 
> On Tue, Jul 23, 2013 at 1:47 PM, Lee Azzarello <lee at guardianproject.info>wrote:
> 
>> Hello all,
>>
>> There have been some conversations recently on IRC and on the web
>> about VBR audio codecs and plaintext recovery.
>>
>> It's an interesting conversation and one which will change a lot in
>> our times. While I was testing some video call clients, I saw a bug
>> between a custom build of Linphone on Android and a nightly of Jitsi
>> on OS X where Linphone tried to play back the encrypted audio through
>> the speaker without first decrypting it.
>>
>> This is what a SRTP audio stream sounds like to a wiretap. The codec
>> is speex at 16 kHZ, I believe it is VBR but I'm not certain.
>>
>> http://ge.tt/9FG7Tem/v/0?c
>>
>> -lee
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