Question: What is the requirement for implementing ESP encryption transforms in a 3GPP Network Domain Security (NDS) context, specifically regarding support for algorithms as per external standards?
Option 1: Implementations MAY choose to support any ESP encryption algorithm, with no specific requirements from external standards.
Option 2: Implementations MUST support ESP encryption algorithms marked as "MUST" in the referenced external standard, exclusively using those mentioned therein.
Option 3: The use of ESP encryption transforms is optional, and there are no specified requirements for algorithm support from external standards.
Option 4: Implementations SHOULD support all ESP encryption algorithms listed in the external standard, but are not required to do so.
Explanation: In the context of 3GPP Network Domain Security (NDS), adherence to external standards is crucial. The correct answer reflects the necessity of supporting specific ESP encryption algorithms as mandated by these standards, ensuring interoperability and security across networks.