F5 is a JPEG-domain steganography technique that modifies quantized DCT coefficients while avoiding some of the most obvious artifacts produced by earlier JPEG embedding approaches.
Use in tools
F5 is treated here as its own technique family. When a tool implements F5 or a close variant, it should be compared at the method level rather than grouped only under generic older JPEG-domain tools.
Detectability results
In the current StegoWatch comparison, F5 should be interpreted as part of the class of older JPEG-domain methods. Its detectability is expected to be higher than more adaptive JPEG methods such as J-UNIWARD under comparable conditions.