Penggabungan Teknik Kompresi Data dan Enkripsi Sandi Alir Untuk Keamanan Citra Digital

Abstract

One of the most common information form is image. Some certain images are strictly confidential, therefore, it has to be kept confidential. The process of maintaining its confidentiality is related to cryptography. Cryptography has two main components, encryption and decryption. In many cases, confidentiality is not the only issue, but also how the data is stored and transferred. To solve these issues, data compression is required. The purpose of this research is to apply data compression techniques and stream ciphers encryption for digital image, and to analyze the result. This research uses DCT method and quantization with compression level 50 (in 1-100 scale). LFSR method is used to generate a key. Then, PSNR value of the decrypted image is calculated. As a result, this research shows that the compression process affects encryption time, the time required to encrypt and decrypt an image is getting longer as the size of the image grows.