In the field of computer software (code) security, it is known to include verification data such as hash values in or associated with the code to allow subsequent detection of tampering by a attacker with the code. This verification technique is used here in a “White Box” cryptographic process by tying the verification data to the content of functional table lookups present in the object (compiled) code, where values in the table lookups are selectively masked (prior to the source code being compiled into the subject code) by being subject to permutation operations.