Improper Protection against Electromagnetic Fault Injection (EM-FI)

Phase: Architecture and Design; Implementation

• 1. Redundancy - By replicating critical operations and comparing the two outputs can help indicate whether a fault has been injected.
• 2. Error detection and correction codes - Gay, Mael, et al. proposed a new scheme that not only detects faults injected by a malicious adversary but also automatically corrects single nibble/byte errors introduced by low-multiplicity faults.
• 3. Fail by default coding - When checking conditions (switch or if) check all possible cases and fail by default because the default case in a switch (or the else part of a cascaded if-else-if construct) is used for dealing with the last possible (and valid) value without checking. This is prone to fault injection because this alternative is easily selected as a result of potential data manipulation.
• 4. Random Behavior - adding random delays before critical operations, so that timing is not predictable.
• 5. Program Flow Integrity Protection - The program flow can be secured by integrating run-time checking aiming at detecting control flow inconsistencies. One such example is tagging the source code to indicate the points not to be bypassed.
• 6. Sensors - Usage of sensors can detect variations in voltage and current.
• 7. Shields - physical barriers to protect the chips from malicious manipulation.