125kHz EM4100 RFID technology is vulnerable to cloning due to what security limitation?

• A. Excessively long key rotation
• B. Lack of strong encryption for authentication data
• C. Excessive use of dynamic sessions
• D. Overly strong access controls

Answer: (B)

125kHz EM4100 tags carry a fixed, unencrypted identification code and do not perform cryptographic authentication with the reader. Because there’s no encryption or challenge-response proving the tag’s authenticity, an attacker can read the tag’s ID and copy it onto a clone tag. The access system then treats the clone as if it were the original, enabling unauthorized access. This vulnerability comes from the lack of strong encryption for the tag’s authentication data. The other options don’t fit because EM4100 does not implement key rotation, dynamic sessions, or overly strong access controls as part of its fundamental operation.