The current implementation of SecurityPolicy [ECC-B] – ECC-nistP256 relies on AES128-CBC for encryption, as outlined in the specification. However, AES128-CBC should be considered for "legacy" systems only according to (H2020-ICT-2014 – Project 645421, D5.4, ECRYPT-CSA, 02/2018; available at https://www.ecrypt.eu.org/csa/documents/D5.4-FinalAlgKeySizeProt.pdf) , signaling the need for an update to more modern encryption variants.

The report highlights the necessity of transitioning to more robust encryption algorithms, such as AES-128-GCM, for enhanced security and resilience against evolving threats.

To address this concern and ensure the security of OPC UA implementations, it is proposed to update SecurityPolicy [ECC-B] – ECC-nistP256 to utilize AES-128-GCM instead of AES-128-CBC. This transition will align OPC UA with contemporary security practices and provide a stronger defense against potential vulnerabilities.