A memory unit such as a memory card is removably attachable to a data processing unit such as a digital video recorder or an audio recording/reproducing unit. The memory unit includes a non-volatile memory, a security unit for protecting the security of data stored in the non-volatile memory, and an...http://www.google.de/patents/US6618789?utm_source=gb-gplus-sharePatent US6618789 - Security memory card compatible with secure and non-secure data processing systems
