This paper takes a fresh look at security notions for steganography --
the art of encoding secret messages into unsuspicious covertexts
such that an adversary cannot distinguish the resulting stegotexts from original covertexts.
Stegosystems that fulfill the security notion used so far, however, are quite inefficient.
This ... more >>>

In the first part of this work, we introduce a new type of pseudo-random function for which ``aggregate queries'' over exponential-sized sets can be efficiently answered. An example of an aggregate query may be the product of all function values belonging to an exponential-sized interval, or the sum of all ... more >>>

The study of monotonicity and negation complexity for Boolean functions has been prevalent in complexity theory as well as in computational learning theory, but little attention has been given to it in the cryptographic context. Recently, Goldreich and Izsak (2012) have initiated a study of whether cryptographic primitives can be ... more >>>