CD-reading for random keys
Doe anyone know where sample code exists to enable one to read the digital stream from an audio CD? If so, I'd appreciate some pointers to it via email. It seems to me like an Audio Cd would make the perfect one-time crypto system. You merely start reading at a specific spot, tossing away bytes using a reproducable random number generator, then permuting those to form a XOR one time key of any length you want. All that would be required to decrypt it would be a CD, the starting point, and the encryption/decryption software. The first step is to be able to read an arbitray sequence of digital samples from an arbitrary spot on a CD. I'm currently looking for software (perferably source) to enable me to do that. Cheers Woody -- Woody Baker Postscript consultant/ hired software gun /flintknapper knapper@bga.com woody@knapper.cactus.org "If you ain't bleedin' you ain't knappin'" -->go ahead, ask me!
In article <4i91h4$lp5@nero.omega.co.nz>, bruce@omega.co.nz wrote:
Doe anyone know where sample code exists to enable one to read the digital stream from an audio CD? <edit> crypto system. You merely start reading at a specific spot, tossing away bytes using a reproducable random number generator, then permuting those to form a XOR one time key of any length you want.
The "entropy" or randomness of audio data is LOW. That's why audio compresses so well. However, the idea of keeping a one-time key on CD-ROM is good.
CD-ROM--good. CD-Audio--weeeelll...could be trouble. Keep in mind Red Book audio does not require 100% error correction, so it would be pretty likely the keys would not match given the tiniest data hiccup. A data mode should work (i'd think). <edit>Then you can send up to 600M of totally secure data before you
dispose of the disks (Microwave oven is fun :) and write a new pair.
3-4 sec. on High; no more, no less. Remove the oven bulb beforehand for best viewing:) ))Sonic(( over 1192 CD players served, but who's counting? -- All spelling & grammar errors ©1996 Sonic Purity. § Now available in two tasty flavors: new (sonicpty@sirius.com) and original (sonicpure@aol.com) § @@ Demopublicans are dead, @ @ Support free speech online ribbons are blue: @ @ (and everywhere else too) @@ @ @ @ @ @ @
Doe anyone know where sample code exists to enable one to read the digital stream from an audio CD? If so, I'd appreciate some pointers to it via email. It seems to me like an Audio Cd would make the perfect one-time
cdgrab (registered) will let you read "frames" (1/75sec of audio) directly into a wav file. From there it's easy.. But:
crypto system. You merely start reading at a specific spot, tossing away bytes using a reproducable random number generator, then permuting those to form a XOR one time key of any length you want.
The "entropy" or randomness of audio data is LOW. That's why audio compresses so well. However, the idea of keeping a one-time key on CD-ROM is good. I would suggest recording thermal noise (Eg the hiss from an untuned FM radio), perhaps XORing with a pseudo-random sequence to remove residual bias. Record 600M of this onto a pair of writable CDs, and have your friend come and collect one of them personally. Then you can send up to 600M of totally secure data before you dispose of the disks (Microwave oven is fun :) and write a new pair. -- bruce@omega.co.nz .-'~~~-. Fax: +64 7 847-5513 .'o oOOOo`. Voice: NISTIM0L0C :~~~-.oOo o`. Fight Elected Dictatorship PGP key available at: `. \ ~-. oOOo. pgp-public-keys@keys.pgp.net `.; / ~. OO: 2001/009734B1 or .' ;-- `.o.' SPLIT YOUR VOTE! 1024/842510D9 ,' ; ~~--'~ \|/ ; ; ____\|//_______\|/________\\;_\\//___\|/___
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bruce＠omega.co.nz -
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sonicpty＠sirius.com