Asymptotic nonlinearity of vectorial Boolean functions

The nonlinearity of a Boolean function $F: \mathbb{F}_{2}^{m}\rightarrow \mathbb{F}_{2}$ is the minimum Hamming distance between f and all affine functions. The nonlinearity of a S-box $f: \mathbb{F}_{2}^{m}\rightarrow \mathbb{F}_{2}^{n}$ is the minimum nonlinearity of its component (Boolean) functions $v\cdot f,\, v\in \mathbb{F}_{2}^{n}\,\backslash \{0\}$ . This notion quantifies the level of resistance of the S-box to the linear attack. In this paper, the distribution of the nonlinearity of (m, n)-functions is investigated. When n?=?1, it is known that asymptotically, almost all m-variable Boolean functions have high nonlinearities. We extend this result to (m, n)-functions.