Comparação de técnicas de esteganografia aplicadas a marca d'água digital

Abstract

Steganography comes from the Greek, meaning, "hidden writing", for centuries, people have pursued ways to communicate securely. The digital watermark makes use of steganography techniques to ensure the authenticity and authorship of a picture or other digital media, through its incorporation. However, the use of watermarks in images suffers with attacks and characteristics by itself, such as compression. This study aims to use different steganographics algorithms applied and adapted to work with digital watermark in color images. The objective is to find the most efficient way to ensure the authenticity of a digital image, focusing on robustness. This work have submitting various algorithms to several attacks and situations, getting as a result the watermark previously incorporated and metrics to evaluate objectively and subjectively the performance of each process. The algorithms were subjected to a variety of different images and watermarks allowing an overview of the each one’s behavior in several environments. None of the attacks was capable to destroy the watermark without affecting image quality. The Fusion and DCT AC algorithms presented the best overall performance, while the JPEG format is a challenge for steganography.