The chapter introduces the F5 steganographic algorithm, which is designed to resist both visual and statistical attacks while maintaining a high capacity for embedding messages. The algorithm uses matrix encoding to enhance embedding efficiency by reducing the number of necessary changes and employs permutative straddling to distribute these changes uniformly across the steganogram. The introduction highlights the limitations of existing steganographic systems, such as Jsteg, which offers high capacity but is vulnerable to statistical attacks, and MP3Stego and IVS-Stego, which are effective against visual and auditory attacks but have very low embedding rates. The chapter also provides an overview of the JPEG File Interchange Format (JFIF), explaining its lossy compression process and the characteristics of the frequency coefficients used in the embedding process.The chapter introduces the F5 steganographic algorithm, which is designed to resist both visual and statistical attacks while maintaining a high capacity for embedding messages. The algorithm uses matrix encoding to enhance embedding efficiency by reducing the number of necessary changes and employs permutative straddling to distribute these changes uniformly across the steganogram. The introduction highlights the limitations of existing steganographic systems, such as Jsteg, which offers high capacity but is vulnerable to statistical attacks, and MP3Stego and IVS-Stego, which are effective against visual and auditory attacks but have very low embedding rates. The chapter also provides an overview of the JPEG File Interchange Format (JFIF), explaining its lossy compression process and the characteristics of the frequency coefficients used in the embedding process.