Advances in NIST Symmetric-Key Standards: Ascon, Accordion, and Wide-AES

Abstract: This talk provides an update on several NIST efforts in symmetric-key cryptography, including Lightweight Cryptography (LWC), the Accordion project, and work on wide-block ciphers. It reviews the status of the LWC standardization effort, highlighting the selection of Ascon and ongoing activities to support secure and efficient deployment in constrained environments. The talk also introduces Accordion, a new initiative focused on flexible authenticated-encryption modes that address a range of security and performance requirements, and discusses its design goals, security properties, and relationship to existing NIST-approved modes. Finally, the talk describes NIST’s decision to proceed with standardization work on Rijndael with 256-bit blocks (Rijndael-256), motivated by feedback on existing block-cipher modes and increasing demands for large-data processing.

Presented by Meltem Sönmez Turan

[Slides] Suggested readings:

• NIST IR 8552: Requirements for Cryptographic Accordions
• SP 800 232: Ascon-Based Lightweight Cryptography Standards for Constrained Devices: Authenticated Encryption, Hash, and Extendable Output Functions