Abstract
Student grade data is personal data that must be protected under Indonesian Law Number 27 of 2022 on Personal Data Protection, yet the rising number of data breaches in the education sector shows that such protection has not been optimally implemented. This study implements the 128-bit Advanced Encryption Standard (AES) algorithm combined with Huffman compression to protect the confidentiality and integrity of student grade files in Excel (.xlsx) format, and evaluates its effectiveness through functional, performance, and security testing. The system was developed as a Python desktop application with a CustomTkinter interface, in which the encryption process runs Huffman compression before AES-128, while integrity verification uses SHA-256 hashing. Testing was conducted on seven student grade files from MA Ma'ahid Kudus. The results show that all files were successfully encrypted and decrypted without failure or data alteration, with encryption times of 0.0142-0.0828 seconds and decryption times of 0.0046-0.1417 seconds. The SHA-256 hash values of the original and decrypted files were identical for all samples, yielding 100% recovery accuracy, while the file size increase from padding and header insertion ranged only from 1,092 to 1,101 bytes. The study concludes that the combination of AES-128 and Huffman compression is an effective and efficient solution for protecting student grade data in educational institutions.
