A method and apparatus are provided for personalizing content on a mobile phone, device or terminal, as any other type of user equipment, instead of the personalization being performed by a network infrastructure device such as a voucher server. The mobile phone, device or terminal has a voucher-driven on-device content personalization module for personalizing the content based on information contained in a rights expression voucher that accompanies the content. The mobile phone, device or terminal personalizes the content without server-side support from the wireless network infrastructure. The rights expression voucher contains information that controls the content personalization in the device. When the device or terminal receives content with this kind of rights expression voucher, it starts personalization operation according to personalization information. This personalization operation can personalize content to the same "individuals" as the server-based personalization. In addition, the device-based personalization operation can use personalization information not known by the voucher server (for example, device specific hardware operations). The personalization can be made by the local encryption of the content encryption key.