Computer-readable medium provided with a memory area (2; 26, 28) for storing data and a distinct microprocessor (3) having a communication interface (4), a memory unit (7) and a processor unit (5) connected to both the communication interface (4) and the memory unit (7). The data may include a first data portion which is arranged to be read and decrypted by a computer arrangement (11) provided at least one condition is met, and the microprocessor (3) being arranged to generate at least one cryptographic key once the condition is met that is necessary to decrypt the data. The invention is also directed to a computer arrangement arranged to communicate with such a medium.