Security
The security of the keystream generation of QUAD is provably reducible to the conjectured intractability of the MQ problem, namely solving a multivariate system of quadratic equations. The first proof was done over field GF(2) for an old-fashioned stream cipher (where the key is the initial state). It was later extended by Berbain and Gilbert in order to take into account the set-up procedure of a modern cipher (with a setup stage deriving the initial state from the key). The security of the whole cipher as a Pseudo Random Function can be related to the conjectured intractability of the MQ problem. The authors also studied the resistance of the cipher against classical attacks.
Read more about this topic: QUAD (cipher)
Famous quotes containing the word security:
“The reins of government have been so long slackened, that I fear the people will not quietly submit to those restraints which are necessary for the peace and security of the community.”
—Abigail Adams (1744–1818)
“I think the girl who is able to earn her own living and pay her own way should be as happy as anybody on earth. The sense of independence and security is very sweet.”
—Susan B. Anthony (1820–1906)
“There is one safeguard known generally to the wise, which is an advantage and security to all, but especially to democracies as against despots. What is it? Distrust.”
—Demosthenes (c. 384–322 B.C.)