IPG Algorith Broken!
paul at fatmans.demon.co.uk
paul at fatmans.demon.co.uk
Tue Nov 26 09:48:41 PST 1996
Known-plaintext: Unbreakable, since the pad is never reused
Chosen-plaintext: Unbreakable, ditto
Adaptive-chosen-plaintext: Unbreakable, ditto
Correct but for a different reason. Re-using the pad does render the
security useless but the other reason is if we know part of the pad
AND the ciphertext (and hence the plaintext) or part of the plaintext
and the ciphertext and therefore the pad, We cannot solve the rest of
the ciphertext as the pad is true random and the next bits are
independent of all the previous ones so we cannot predict from what
we have.
A better definition of unbreakable, IMHO, is that there is no way to
determine the plaintext given unlimited ciphertext and computational
resources. Sure, this isn`t a complete definition but at least it
definites perfect security in an analytic sense.
Datacomms Technologies web authoring and data security
Paul Bradley, Paul at fatmans.demon.co.uk
Paul at crypto.uk.eu.org, Paul at cryptography.uk.eu.org
Http://www.cryptography.home.ml.org/
Email for PGP public key, ID: 5BBFAEB1
"Don`t forget to mount a scratch monkey"
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