Techniques used to alter information within a patient's EHR include data encryption, obfuscation, hashing, exclusion and perturbation.
When patients apply for masking of their EHR, health services must meet their needs and alter the system accordingly so that unauthorised individuals can't gain access.
[6] In patient care, authorised users have the ability to override masking and access restrictions under emergency circumstances.
[10] Masking refers to sets of alterations and changes made to protect information within the confines of Electronic health records.
In general, direct identifiers are removed from the dataset, replaced with random values, changed using the hashing function, or restored with a unique key.