Provides a data processing system comprising a processor and encrypted information in a first persistent memory whose level of information leakage is higher than that of a second persistent memory. The second persistent memory stores a cryptographic key for decrypting the encrypted information, generating therefrom unencrypted information that is usable by the processor for executing an operation. The cryptographic key may be used for encrypting the unencrypted information, generating the encrypted information. Also provided is a method of processing such a data-processing system with an operating system, comprising writing unencrypted information into the first persistent memory, encrypting the unencrypted information under use of the first cryptographic key, creating therefrom encrypted information in the first persistent memory, and setting the data-processing system to a state in which writing into the first persistent memory is controlled by the operating system.