5.5.1. GCM Padding - 2026-02-24

Symmetric Cryptographic Accelerator Hard IP User Guide

Version
25.3
Product Type
Device Families > Agilex Families
Device Families > Agilex Families > Agilex 7 > F-Series
Device Families > Agilex Families > Agilex 7
Device Families > Agilex Families > Agilex 7 > I-Series
Resource Type
Documentation > User Guides
ft:sourceName
DITA

This block implements the idle bytes padding to the AAD and Bypass fields, which are not 16 byte-aligned if you turn on Enable Gen. GCM AAD-Bypass ingress padding in the IP parameter editor. You must send in the real AAD and Bypass fields length.

If you do not turn on Enable Gen. GCM AAD-Bypass ingress padding in the IP parameter editor, the padding logic within the IP is optimized away to save device resources.
Figure 15. GCM Padding