{"construction": "CBC-MAC with zero IV and 16-byte blocks", "block_size": 16, "message_hex": "726f6c653d67756573743b6f703d3121", "message_tag": "000f0e58135808121716041544100002", "target_hex": "726f6c653d61646d696e3b6f703d3121", "target_tag": "000f0e58154900080d16041544100002", "accepted_message_length": 32, "investigation": "Track the chaining value at each block boundary."}