2. Then take an encrypted PGP file and dispurse it bit-by-bit into the LSB (least-significant-bit) of each sample. This wouldn't distort the sound sample to any extent noticable by the human ear. Thus each byte of PGP file would be dispursed into 8 bytes of sound file. Thus if you wanted to send a 20k PGP file, you would have to put it into a 160k music file. If you're ever forced to explain what that file contains (unlikely, since you can always take the Fifth Ammendment) you can just play it on your computer and have the NSA/SS/FBI/Whatever listen to James Brown go "Hyeeeah... I feel good!"
a) This method has essentially the same complexity, as one-time pad, but without it's strength.
Insert pgp-encrypted (not plaintext) into the sound file... It's then no weaker that pgp.
b) If it's played and recognized - one can trace your source (a CD, a tape of radio broadcast, whatever) and do a comparison. Then the file containing of all the LSBs is cryptanalyzed...
Use a "windows sound system" board and record yourself talking -- No "reference source"... The codec on that board has better than two bits of noise per 16 bit word through the ADC channel... Nice idea, thug! =================================================================== Eric Fogleman eric.fogleman@analog.com Analog Devices Semiconductor Voice: (617) 937-2275 804 Woburn Street Fax: (617) 937-2024 Wilmington, MA 01887-3462 ===================================================================
Eric Fogleman writes:
a) This method has essentially the same complexity, as one-time pad, but without it's strength. Insert pgp-encrypted (not plaintext) into the sound file... It's then no weaker that pgp.
Please... I said: "It's as cumbersome, as one-time pad, but without one-time pad security." Yes, it can be made as secure as PGP, but it's still less safe, than one-time pad.
Use a "windows sound system" board and record yourself talking -- No "reference source"... The codec on that board has better than two bits of noise per 16 bit word through the ADC channel...
Then you're creating a sort-of one-time pad, which you now must convey securely to your correspondent. And this system is still much less safe, than one-time pad, because of some possible regularities in the lower bits (now I admit I know very little of what such a recording would look like, so in fact it MIGHT be as safe as "real" one-time pad). Regards, Uri. ------------ <Disclaimer>
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Eric Fogleman -
uri＠watson.ibm.com