Devices and methods for masking and unmasking sensitive data, based on a standard cryptographic algorithm defining a ciphering algorithm, and a deciphering algorithm using more resources than the ciphering algorithm are described. The masking of sensitive data is done by applying the deciphering algorithm to the sensitive data to obtain masked sensitive data. The unmasking of the masked sensitive data is done by applying the ciphering algorithm to the masked sensitive data to obtain sensitive data in plain form.