Testability is a major issue, particularly for secure chips. Design-for-Testability techniques based on scan chains proved to be a highway for potential attacks. BIST approaches appear as good alternatives since they do not rely on visible scan chains. In this paper we propose a generic BIST solution for block-cipher devices. Taking advantage of the iterative process involved in such encryption algorithms which results in structural implementation consisting of (quasi) identical round transformations executed by the same piece of hardware, self-test procedures are easily setup. Compared to classical BIST solutions based on pseudo-random test pattern generation and output responses compactors, its main advantages are a negligible area overhead and a very short test time, while guaranteeing 100% of fault coverage.