IACR News item: 24 April 2015
Daniel R. L. Brown
ePrint Reportpublic but unpredictable random function to the source key. A
remixed key models a key derived from a shared secret and a public
unpredictable salt, using a common, deterministic, pseudorandom
function---which is somewhat like TLS record-layer keys.
This report tries to validate the intuition that remixed keys are not
easy to surmise, in other words, that remixing does not introduce an
exploitable spike in the probability distribution of the remixed
key. The report provides pencil-and-paper proofs of numerical
bounds on the probability that an adversary can surmise a remixed
key, assuming a uniformly random source key and remix function. The
proofs are derived from a proof of an asymptotic result on
probability theory in a textbook by Shoup.
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