18 research outputs found
Factoring multivariate polynomials over finite fields
AbstractThis paper describes an algorithm for the factorization of multivariate polynomials with coefficients in a finite field that is polynomial-time in the degrees of the polynomial to be factored. The algorithm makes use of a new basis reduction algorithm for lattices over Fq[Y]
Chosen-Prefix Collisions for MD5 and Applications
We present a novel, automated way to find differential paths for MD5.
Its main application is in the construction of \emph{chosen-prefix collisions}.
We have shown how, at an approximate expected cost of
calls to the MD5 compression function, for any two chosen message
prefixes and , suffixes and can be constructed such that
the concatenated values and collide under MD5.
The practical attack potential of this construction
of chosen-prefix collisions is of greater concern
than the MD5-collisions that were published before. This is illustrated by
a pair of MD5-based X.509 certificates one of which was signed by a
commercial Certification Authority (CA) as a legitimate website certificate,
while the other one is a certificate for a rogue CA that is entirely
under our control (cf.\ \url{http://www.win.tue.nl/hashclash/rogue-ca/}).
Other examples, such as MD5-colliding executables, are presented as well.
More details can be found on
\url{http://www.win.tue.nl/hashclash/ChosenPrefixCollisions/}