- Fidelity, the quality of container images has not changed much, after the addition of confidential data, the results of steganography images still look well. Observers do not know that in the image there is confidential data.
- Robustness, the hidden data must be resistant to manipulation carried out on container images "such as" changing contrast, sharpening, placement, adding noise, enlarging images, cutting "cropping", encryption and so on "if the image processing operations are carried out the data hidden not broken.
- Recovery, hidden data must be able to disclose "recovery" because the purpose of steganography is hiding data so that at any time confidential data in the image of the container must be retrieved for further use.
- Capacity "capacity" refers to the amount of information that can be hidden in a cover medium. Security is the observer's inability to detect hidden messages and resilience is the amount of modification of the stego medium that can survive before the enemy destroys the hidden secret message.
- Security "security", security of the classic steganography system embodies the confidentiality of its encoding system. Information theory allows us to be more specific to what is meant by a system that is truly safe.
- "Robustness", resistance refers to cross-sectional image data "such as changing contrast, sharpening, rotation, magnification of images, cuts and so on". If the image is carried out by image processing operations, then the hidden data is not damaged.
Types of Steganography Techniques
- Injection, is a technique to embed secret messages directly into a media. One problem with this technique is that the size of the injected media becomes larger than its normal size so that it is easily detected. This technique is often also called embedding.
- Substitution, normal data is replaced with confidential data. Usually the results of this technique do not change the size of the original data too much, but depends on the media files and data that will be hidden. Substitution techniques can reduce the median quality that is boarded.
- Tramsformation Domain, this technique is very effective. Basically, domain transforms hide data on transformspace.
- SpreadSpectrum, is a transmission technique using pseudo-noise code, which is independent of information data as a waveform modulator to spread signal energy in a "bandwidth" communication path that is greater than the information communication path signal. By the receiver, the signal is collected again using synchronized pseudo-noise code replicas.
- Statistical Method, this technique is also called the 1-bit steganographic scheme, the scheme implements one bit of information in the media ride and changes the statistics even if only 1 bity. Statistical changes are indicated by indication 1 and if there are no regulations it looks indication 0. This system works based on the ability of the recipient to distinguish between information that has been modified and what has not.
- Distortion, this method creates changes to objects that are carried by secret data.
- Cover Generation, this method is more unique than other methods because the cover object is chosen to hide the message.
Source : https://www.dosenpendidikan.com/steganografi-pengertian-prinsip-kriteria-aspek-jenis/