| Function | Detailed function | Related steps |
| F1 (disk management) | (i) File generation (ii) File opening (iii) File closing (iv) File deletion | (i) Registration process: Steps 5, 6, 7, and 8 (ii) Authentication process: Steps 1 and 8 |
| F2 (user authentication) | (i) ID/PW (ii) Possible application of additional device authentication to improve security | (i) Registration process: Steps 1, 2, 3, 4, 14, 15, 16, 17, 18, and 19 (ii) Authentication process: Steps 2, 3, 4, 5, 6, and 7 |
| F3 (data protection) | (i) Data encryption/decryption | (i) Registration process: Steps 9, 10, 11, 12, 13, and 19 (ii) Authentication process: Step 7 | (ii) Saving of additional random number and use of hash chain to improve security |
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