Administrative workflows refer to variable business processes in which all cases are known; tasks are predictable and their sequencing rules are simple and clearly defined. When such processes are collaboratively executed by several actors, it may be desirable, for security reasons (confidentiality), that each of them has at all times, only a partial perception (this is what we call "actor's view") of the current process state. This concern seems sufficiently important to be considered when specifying such workflows. However, traditional workflow specification languages (BPMN, BPEL, YAWL) only partially address it. This is why we present in this paper, a new language for specifying administrative workflows that allows us not only to simply model all of the processes tasks and their sequence, but also and especially to explicitly express the rights of the various actors with respect to each of them, in order to guarantee a certain degree of security. The proposed model is an executable grammatical specification that allows to express using decorated productions, the different types of basic flows (sequential, parallel, alternative and iterative) that are found in workflow specification languages; moreover, it also allows to specify the rights of each actor in each process and on its data in a formalism similar to that used in UNIX-like operating systems.