Symmetric Cryptographic Intel FPGA Hard IP User Guide

ID 714305
Date 10/02/2023
Public
Document Table of Contents

5.5.1. GCM Padding

This block implements the idle bytes padding to the AAD and Bypass fields which are not 16 byte-aligned when "Enable Gen. GCM AAD-Bypass ingress padding" is selected in the IP GUI. You are required to send in the real AAD and Bypass fields length.

When "Enable Gen. GCM AAD-Bypass ingress padding" is not selected in the IP GUI, the padding logic within the IP is optimized away in order to save device resources.
Figure 15. GCM Padding