Question: In a concatenated SMS message with a Security Header, as per 3GPP specifications, where is the Security Header located?
Option 1: In every segment of the concatenated message to ensure security across all parts.
Option 2: Only in the last segment of the concatenated message for final verification.
Option 3: Exclusively in the first segment of the concatenated message, with subsequent segments relying on initial authentication.
Option 4: Its location varies based on the type of SMS compression algorithm utilized (if any).
Explanation: According to specifications for handling Security Headers in SMS messages, particularly in scenarios involving concatenated messages, the Security Header is only present in the first segment. This approach ensures that the initial part of the message, which sets up the security context, is properly secured without unnecessarily duplicating security information across all segments, thus optimizing resource usage while maintaining security integrity.