▎ 摘　　要

NOVELTY - A graphene quantum dot solution is prepared by adding phenol organic substance into anhydrous ethanol, completely dissolving, transferring into hydrothermal reaction kettle and reacting at 160-220 degrees C for 10-18 hours. USE - Method for preparing graphene quantum dot solution used for graphene quantum dot security ink (claimed). ADVANTAGE - The graphene quantum dot solution has easy preparation, low toxicity and low cost, and is environment-friendly. The security ink is convenient to carry, and has fast encryption and decryption time. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for information security method comprising spraying, printing or writing graphene quantum dot security ink on acid-treated wood fiber paper with encrypted information.