Patent ID: 11943332
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 5:
6. The SBox circuit according to claim 1, wherein:
the first circuit part and the second circuit part are configured to generate the 4-bit first output signal (Y) and the 32-bit second output signal (L) in accordance with a forward SBox operation; and
the SBox circuit further comprises:
a fourth circuit part comprising digital circuitry that generates an alternative 4-bit output signal (Yalt) from the 8-bit input signal (U) for use in an inverse SBox operation;
a fifth circuit part, configured to operate in parallel with the fourth circuit part and to generate an alternative 32-bit second output signal (Lalt) from the 8-bit input signal (U) for use in the inverse SBox operation, wherein the alternative 32-bit second output signal (Lalt) consists of four 8-bit sub-results; and
a selection circuit that is controllable to engage the first and second circuit parts when a forward SBox operation is selected, and to engage the fourth and fifth circuit parts when an inverse SBox operation is selected.