What Is Digital steganography

Modern steganography entered the world in 1985 with the advent of the personal computer being applied to classical steganography problems. Development following that was slow, but has since taken off, going by the number of "stego" programs available: Over 800 digital steganography applications have been
identified by the Steganography Analysis and Research Center. Digital steganography techniques include:

• Concealing messages within the lowest bits of noisy images or sound files.
• Concealing data within encrypted data or within random data. The data to be concealed is first encrypted before being used to overwrite part of a much larger block of encrypted data or a block of random data (an unbreakable cipher like the one-time pad generates ciphertexts that look perfectly random if you don't have the private key).
• Chaffing and winnowing.
• Mimic functions convert one file to have the statistical profile of another. This can thwart statistical methods that help brute-force attacks identify the right solution in a ciphertext-only attack.
• Concealed messages in tampered executable files, exploiting redundancy in the targeted instruction set.
• Pictures embedded in video material (optionally played at slower or faster speed).
• Injecting imperceptible delays to packets sent over the network from the keyboard. Delays in keypresses in some applications (telnet or remote desktop software) can mean a delay in packets, and the delays in the packets can be used to encode data.
• Changing the order of elements in a set.
• Content-Aware Steganography hides information in the semantics a human user assigns to a datagram. These systems offer security against a non-human adversary/warden.
• Blog-Steganography. Messages are fractionalized and the (encrypted) pieces are added as comments of orphaned web-logs (or pin boards on social network platforms). In this case the selection of blogs is the symmetric key that sender and recipient are using; the carrier of the hidden message is the whole blogosphere.
• Modifying the echo of a sound file (Echo Steganography)