Security of multimedia files attracts more and more attention and many encryption methods have been proposed in literature. However most cryptographic systems deal with multimedia files as binary large objects, without taking into consideration regions of semantic information. These regions may need better protection or can be the only regions that need protection, depending on the specific application. Towards this direction, in this paper we propose a human video object encryption system based on the chaotic logistic map. Initially face regions are efficiently detected and afterwards body regions are extracted, using geometric information of the location of face regions. Next the pixels of extracted human video objects are encrypted using an iterative cipher module, which is based on a feedback mechanism responsible for mixing the current encryption parameters with encrypted information of the previous step. The system presents robustness against known cryptanalytic attacks, and can save us a great amount of computational resources and time devoted for encrypting the whole contents of a multimedia file.