33   Clarification of AEAD handling for Secure Data Messages

Created: 01 Sep 2023

Status: Triage

Part: Part 5 (2023, Edition 1, IS)

Links:

Page: 99

Clause: 8.5.2.2.6.3

Paragraph: 1

Issue

Based on discussion of AEAD realization in the course of updating IEC 60870-5-7 there were different interpretations of the message processing specification in section "8.5.2.2.6.3 Secure Data Payload using AEAD algorithm" in IEC 62351-5:2023. Note that there was a discussion about the encryption of the ADL value and there was a deliberate decision to stay with the description to stay with the encryption of the ADL value.

Proposal

It is proposed to include the following text and the attached figure at the end of clause "8.5.2.2.6.3 Secure Data Payload using AEAD algorithm":

"The following figure depicts the secure data message and specifically, how the different components of the message are treated in the context of the AEAD algorithm. The figure is provided in addition to table 29 and the description in this section to avoid potential ambiguities and to provide clarity for the implementation."