Improvement of PSNR by Using Shannon-Fano Compression Technique in AES-LSB StegoCrypto

One way to write information data is by using cryptography and steganography. Cryptography converts information messages into a form that can no longer be understood. In comparison, steganography is used to insert a secret message into the container media such as images or sounds so that someone will not be aware of the existence of the secret message. The combination of cryptography and steganography methods aims to provide a high level of security for information data. In this paper, we propose the use of the Shannon-Fano compression technique to increase the PSNR (Peak Signal-to-Noise Ratio) value of the steganography image. The StegoCrypto algorithm used is the AES (Advanced Encryption Standard) cryptographic algorithm which is the current standard for symmetric key encryption and the LSB (Least Significant Bit) steganography method. The use of the compression technique with the Shannon-Fano method aims to reduce the amount of embedded data so that it increases the value of the PSNR steganography image. From the test results, the resulting performance for the PSNR value from the combination of methods produces a value above 40, which means it is still above the criteria for a good steganography image and up to 2.785 dB or 89% better than a system that does not use a compression process.