Which level of AES encryption does Cisco Unified Presence and Cisco Unified Communications IM and Presence use?

Cisco Unified Communications IM and Presence employs 256-bit AES for encrypting XMPP federation traffic and stored data, providing the highest standard AES key length for maximum security. This aligns with Cisco's security hardening guidance for the IM and Presence service and satisfies modern compliance requirements.

128-bit AES is a valid AES key size but is not the level specified for Cisco Unified Presence and IM and Presence encryption.

2048-bit is a key size associated with RSA asymmetric encryption, not AES symmetric encryption.

8-bit is not a valid AES key size; AES is standardized at 128, 192, or 256 bits.

512-bit is not a defined AES key size; no NIST-standard AES variant uses 512-bit keys.