Abstract. Current mobile digital communication systems must implement rigorous operations to guarantee high levels of confidentiality and integrity during transmission of critical information. To achieve higher performance, the security algorithms are usually implemented as dedicated hardware functional units attached to the main processing units of the embedded communication system. To save hardware resources, the designer usually performs a number of manipulations in the cipher algorithm lying at the core of the confidentiality and integrity operations to implement a simplified version of it that is suitable to be efficiently used in an embedded environment. This paper describes an extension to UML 2.0 to model the structure of contemporary block cipher algorithms, with the ultimate goal of synthesizing representations in a hardware description language from these models according to a modeldriven development principle. This automated process should alleviate design complexity and in...