In one embodiment, a first apparatus includes a processor and an interface, wherein the interface is operative to receive a request from a second apparatus to commence a keyed-hash message authentication code (HMAC) computation, the processor is operative to perform a first computation computing a first part of the HMAC computation using a secret key K as input yielding a first value, the interface is operative to send the first value to the second apparatus, the interface is operative to receive a second value from the second apparatus, the second value resulting from the second apparatus processing the first value with at least part of a message M, the processor is operative to perform a second computation based on the second value and the secret key K yielding an HMAC value, and the interface is operative to send the HMAC value to the second apparatus.