1. A method comprising: obtaining program information to an execution environment comprised in an electronic device, said program information comprising at least a program code; computing a confidentiality key of at least part of said program information and a secret value specific to said electronic device; and applying a cryptographic operation, with said confidentiality key as the key, to a first data element comprising a first input data element to said program code or a first output data element from said program code, said cryptographic operation comprising at least one of decryption and encryption.