Implementasi Kombinasi Kriptografi Hill Cipher dan Steganografi Discrete Wavelet Transform pada Citra Digital

Muhammad, Ilyas (2026) Implementasi Kombinasi Kriptografi Hill Cipher dan Steganografi Discrete Wavelet Transform pada Citra Digital. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Perkembangan pertukaran data digital melalui jaringan publik meningkatkan risiko penyadapan, modifikasi, dan penyalahgunaan informasi. Oleh karena itu, diperlukan metode pengamanan yang tidak hanya menjaga kerahasiaan isi pesan, tetapi juga menyembunyikan keberadaan pesan agar tidak mudah dicurigai. Penelitian ini mengimplementasikan kombinasi kriptografi Hill Cipher dan steganografi Discrete Wavelet Transform (DWT) pada citra digital. Pesan rahasia berupa teks ASCII dienkripsi menggunakan Hill Cipher dengan matriks kunci berukuran 2 × 2 dan 3 × 3, kemudian ciphertext dikonversi menjadi bitstream. Selanjutnya, citra cover RGB diproses pada channel biru menggunakan DWT 1-level dengan basis Daubechies 4 (db4), dan bitstream ciphertext disisipkan pada subband LH dan HL menggunakan metode Quantization Index Modulation (QIM). Evaluasi dilakukan berdasarkan kapasitas payload, waktu komputasi, kualitas citra stego menggunakan Mean Squared Error (MSE), Peak Signal to Noise Ratio (PSNR), dan Structural Similarity Index Measure (SSIM), pemulihan pesan menggunakan Bit Error Rate (BER), ketahanan terhadap salt and pepper noise, serta evaluasi visual melalui kuesioner. Hasil pengujian menunjukkan bahwa sistem mampu menyisipkan dan mengekstraksi pesan dengan nilai BER 0% pada kondisi tanpa gangguan. Kualitas citra stego tetap baik, ditunjukkan oleh nilai PSNR yang masih tinggi dan SSIM yang mendekati 1. Namun, pengujian noise menunjukkan bahwa sistem masih sensitif terhadap perubahan piksel acak. Secara keseluruhan, kombinasi Hill Cipher dan DWT mampu menjaga kerahasiaan pesan, mempertahankan kualitas visual citra stego, serta memulihkan pesan secara utuh pada kondisi tanpa gangguan.
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The development of digital data exchange through public networks has increased the risk of eavesdropping, data modification, and information misuse. Therefore, a security method is required that not only protects the confidentiality of message content but also conceals the existence of the message to prevent suspicion. This research implements a combination of Hill Cipher cryptography and Discrete Wavelet Transform (DWT) steganography in digital images. The secret message, in the form of ASCII text, is encrypted using the Hill Cipher with 2×2 and 3×3 key matrices, after which the resulting ciphertext is converted into a bitstream. The RGB cover image is then processed on the blue channel using a one-level DWT with the Daubechies 4 (db4) wavelet basis, and the ciphertext bitstream is embedded into the LH and HL subbands using the Quantization Index Modulation (QIM) method. System performance is evaluated based on payload capacity, computation time, stego-image quality using Mean Squared Error (MSE), Peak Signal-to-Noise Ratio (PSNR), and Structural Similarity Index Measure (SSIM), message recovery using Bit Error Rate (BER), robustness against salt-and-pepper noise, and visual assessment through a user questionnaire. The experimental results show that the proposed system successfully embeds and extracts messages with a BER of 0% under normal conditions without noise. The stego images maintain high visual quality, as indicated by high PSNR values and SSIM values close to 1. However, robustness testing reveals that the system remains sensitive to random pixel modifications caused by salt-and-pepper noise. Overall, the combination of Hill Cipher cryptography and DWT-based steganography effectively preserves message confidentiality, maintains the visual quality of the stego image, and enables complete message recovery under normal operating conditions.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Hill Cipher, Steganografi, Discrete Wavelet Transform, Quantization Index Modulation, Citra Digital, Hill Cipher, Steganography, Discrete Wavelet Transform, Quantization Index Modulation, Digital Image
Subjects:	Q Science > QA Mathematics > QA76.9.A25 Computer security. Digital forensic. Data encryption (Computer science) T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK5102.94 Cryptographic techniques
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Mathematics > 44201-(S1) Undergraduate Thesis
Depositing User:	Ilyas Muhammad
Date Deposited:	31 Jul 2026 03:33
Last Modified:	31 Jul 2026 03:33
URI:	http://repository.its.ac.id/id/eprint/139174

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