Question: What is the format of Client Credentials Assertions (CCAs) in a 5G System security architecture?
Option 1: XML-based tokens with RSA encryption
Option 2: JSON Web Tokens secured with digital signatures based on JSON Web Signature (JWS)
Option 3: Base64-encoded strings with HMAC-SHA256 signature
Option 4: DER-encoded X.509 certificates with ECDSA signature
Explanation: According to the security architecture and procedures for 5G System, CCAs are required to be JSON Web Tokens as described in RFC 7519 and secured with digital signatures based on JSON Web Signature (JWS) as described in RFC 7515. This ensures secure authentication and verification of client credentials in a 5G network.