Barbara Espinoza

Florida International University School of Computing & Information Sciences

Lecture Information:
  • November 29, 2012
  • 2:00 PM
  • ECS: 349

Speaker Bio

Barbara Espinoza is a PhD candidate in the School of Computing &
Information Sciences at Florida International University. She is
currently working with Prof. Geoffrey Smith in the broad area of
quantitative information flow. Barbara received a bachelor’s degree in
Computer Science from Universidad Simon Bolivar in Caracas, Venezuela
in 2006, and joined FIU during Fall 2008. Her research focus is on the
theory and applications of min-entropy leakage.

Description

Theories of quantitative information flow offer an attractive
framework for analyzing confidentiality in practical systems, which
often cannot avoid “small” leaks of confidential information. Recently
there has been growing interest in the theory of min-entropy leakage,
which measures uncertainty based on a random variable’s vulnerability
to being guessed in one try by an adversary. In our work, we
contribute to this theory by studying the min-entropy leakage of
systems formed by cascading two channels together, using the output of
the first channel as the input to the second channel. After
considering the semantics of cascading carefully and exposing some
technical subtleties, we prove that the min-entropy leakage of a
cascade of two channels cannot exceed the leakage of the first
channel; this result is a min-entropy analogue of the classic
data-processing inequality. We show however that a comparable bound
does not hold for the second channel. We then consider the
min-capacity, or maximum leakage over all a priori distributions,
showing that the min-capacity of a cascade of two channels cannot
exceed the min-capacity of either channel.