[messaging] WaveCrypt

Joseph Gentle me at josephg.com
Wed Apr 13 20:34:11 PDT 2016

Yeah this goes back to the old 'three types of crypto tokens':

- What you know (a password)
- What you have (an rsa token, or a phone with google authenticator)
- What you are (fingerprint, retina scan)

Any new crypto system essentially boils down to some combination of
those things. If you're using a CD, you've invented a new kind of
crypto token (what you have). If you're remembering which youtube
video is your key, you're using a (pretty weak) password (what you
know). Still very cool though, if you can play it and have an embedded
device hear the recording. It'd also be very cool to have a little
crypto token that plays what sounds like static, and then have your
computer / phone / whatever unlock when it hears the 'right'
static-sounding audio clip.

The cool thing about audio (for me) would be doing voice
fingerprinting. "My name is my passport. Verify me"

On Thu, Apr 14, 2016 at 11:11 AM, Justin King-Lacroix
<justin.king-lacroix at cs.ox.ac.uk> wrote:
> On 10 April 2016 at 10:27, Mihai Ionut <c.ionutmihai1 at gmail.com> wrote:
>> Hi, I am a 21 years old software engineer from Bucharest, Romania
>> passionate about programming, robotics, cryptography and Artificial
>> intelligence.
>> For the past two months I've worked on a new encryption application based
>> on sounds. It allows users to encrypt their files (AES) using an audio
>> input.
> There's a lot of coolness in this idea. You might want to read up on the use
> of sound card inputs as sources of entropy for random number generators.
>> The users have three options : they can generate their own  WaveKey, they
>> can use an exiting audio file (your favorite song from 1990's stored on a
>> CD) or to use an online audio source - now I'm only focused on YouTube. You
>> simply visit an YouTube video, select the time sequence, generate you
>> WaveKey and encrypt your file. After that the key self-destructs.
> While the idea isn't a bad one in principle, it means you now need to treat
> the relevant YouTube link / song name with the same care as a cryptographic
> key.
> Also, YouTube knows your key.
>> Of course I've taken into account the obvious attacks - like the ones
>> regarding recording when the users create their WaveKeys (I've worked on a
>> custom printed circuit board with an integrated microphone and a small
>> storage USB drive) or, in the case of the YouTube source your search history
>> (We have Sandboxie and I'm pretty sure I can strike a deal with them).
> What you haven't considered is that everyone on the network who can observe
> your YouTube search history now potentially knows your key. Sandboxie only
> prevents your browser from keeping its history on your hard disk; any traces
> you leave on the network -- such as in YouTube's access logs (you weren't
> logged in as yourself when you viewed it, right?) -- are, by nature, not
> eraseable in this fashion.
> On the flip side, generating your own WaveKey also seems problematic: on the
> one hand, you want to filter as much noise as possible out of the audio
> coming into your application, so the key generation is repeatable ie you can
> sing the same song into the same mic again on a different day and decrypt
> your files. On the other, you're throwing away a lot of entropy that way,
> potentially making it easier to just brute-force the key.
> If you solve this problem using a USB drive (or similar) connected to a
> microphone to store the 'authoritative' copy of the recording, and reuse
> that, we're now back to the usual key-management problem, only your key is
> an unwieldy sound recording.
> This idea is cool. However, I believe these issues need to be fixed or
> mitigated before it can be put to practical use.
> </$0.02>
> J
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