DPA countermeasures are unavailable for ECDH key agreement and EdDSA signing operations on Curve25519 and Curve448 on all Series 2 modules and SoCs due to a lack of hardware and software support. A successful DPA attack may result in exposure of confidential information. The best practice is to use the impacted crypto curves and operations with ephemeral keys to reduce the number of DPA traces that can be collected.
A device’s real time power consumption may be monitored during security token evaluation and the information gleaned may be used to determine the value of the reference token.
The power consumed by a device may be instrumented and monitored in real time. If the algorithm for evaluating security tokens is not sufficiently robust, the power consumption may vary by token entry comparison against the reference value. Further, if retries are unlimited, the power difference between a “good” entry and a “bad” entry may be observed and used to determine whether each entry itself is correct thereby allowing unauthorized parties to calculate the reference value.