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:
“A well-regulated militia being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.”
—Second Amendment, U.S. Constitution (1791)
“We now in the United States have more security guards for the rich than we have police services for the poor districts. If you’re looking for personal security, far better to move to the suburbs than to pay taxes in New York.”
—John Kenneth Galbraith (b. 1908)
“Those words freedom and opportunity do not mean a license to climb upwards by pushing other people down. Any paternalistic system that tries to provide for security for everyone from above only calls for an impossible task and a regimentation utterly uncongenial to the spirit of our people.”
—Franklin D. Roosevelt (1882–1945)