Patent ID: 8060757

Claim:
An apparatus for encrypting a datum to be stored during a write access to a memory at an access address into an encrypted datum, comprising: a cryptographic module configured for generating an address-dependent key from the access address and configured for encrypting the datum to be stored using the address-dependent key, wherein the cryptographic module includes a cryptographic calculating unit with a data input, a key input, and a data output, configured for performing a cryptographic algorithm on data at the data input and key input, to output a cryptographic result at the data output; and a controller configured for controlling the cryptographic module, such that in a first phase the access address passes through the cryptographic module in a first data path into which said data input and said data output of the cryptographic calculating unit are connected, and a master key is present at the key input of the cryptographic calculating unit in the first phase when the access address passes through the cryptographic calculating unit, in order to obtain the address-dependent key at an end of the first phase, and in the second phase the datum to be stored passes through a second data path into which said data input and said data output of the cryptographic calculating unit are connected, and the address-dependent key is present at the key input of the cryptographic calculating unit in the second phase when the datum to be stored passes through the cryptographic calculating unit, so that the encrypted datum is obtained at an end of the second phase, wherein at least one of the cryptographic module and the controller comprises a hardware implementation.