Some Recent Results on Fourier Transforms of Boolean Functions Gary McGuire University College, Dublin Abstract: Various types of Boolean functions are used in coding and cryptography. In certain cryptosystems, Almost Perfect Nonlinear functions provide the best resistance to certain types of attack. We present some new APN functions. We will discuss recent calculations of the Fourier spectrum of APN functions. Then we will talk about a recent analysis of the Fourier spectrum of some monomial bent functions using Stickelberger's theorem. Finally, if time permits we discuss connections between bent functions and almost bent functions via restriction.