IMPLEMENTASI ALGORITMA KRIPTOGRAFI ADVANCED ENCRYPTION STANDARD (AES-256) DAN HASH SHA-256 UNTUK PENGAMANAN BERKAS DOKUMEN DIGITAL AKADEMIK

Abstract

Academic digital transformation across modern universities promotes digital degree certificates and transcript distribution in Portable Document Format (PDF). While facilitating archiving and verification logistics, digital documents face acute tampering hazards, unauthorized forgery, and integrity corruption. This research implements an enterprise security framework combining 256-bit Advanced Encryption Standard (AES-256) in Cipher Block Chaining (CBC) mode with Secure Hash Algorithm (SHA-256) to ensure end-to-end confidentiality and immutable document integrity. Built in Python leveraging PyCryptodome cryptographic primitives, performance was benchmarked on digital academic transcripts spanning 250 KB to 10 MB. Experimental benchmarks demonstrated encryption latency ranging from 0.028 to 0.485 seconds and decryption times from 0.022 to 0.392 seconds. The Avalanche Effect evaluation recorded an average bit divergence of 50.42% upon single-bit plaintext perturbations (surpassing the ideal 50% threshold), while SHA-256 hash checks achieved 100% sensitivity in intercepting minute 1-byte tampering attempts.