Question: When reducing the effective key length of the Cipher Key (CK) in a telecom network, how should the remaining bits be handled to maintain security integrity?
Option 1: The least significant bits should be set to a random value to enhance entropy.
Option 2: The most significant bits should be set to zero, and the effective key information should be carried in the least significant bits.
Option 3: The remaining, least significant bits shall be set to zero, while the most significant bits carry the effective key information.
Option 4: All bits should be rearranged according to a predefined permutation to maintain security.
Explanation: This approach ensures that the effective key information is preserved in the most significant bits of the CK, which typically hold more importance in cryptographic operations. Setting the remaining (least significant) bits to zero prevents any potential information leakage and maintains alignment with standardized security practices for key length adjustments.