stegano

Stegano, or steganography, is the practice of concealing messages or information within ordinary data so that the presence of the hidden content is not apparent. The term derives from Greek steganos “covered” and graphein “to write.” In some contexts, stegano or stego is used as a shorthand for the field of steganography, distinguishing the technique from cryptography, which aims to make content unreadable rather than invisible.

Historically, steganography includes methods such as hiding messages in innocuous objects or on shaved heads. In the digital era, it has expanded to embedding information within multimedia files, network protocols, or other digital carriers, making the hidden data difficult to detect without specialized analysis.

Common techniques fall into several categories. Image steganography hides data in pixel values or in the less noticeable bits of color channels. Audio steganography uses subtle alterations to sound samples or echo-based methods. Video steganography extends these ideas to motion pictures, while network steganography exploits protocol fields or timing channels. Text-based methods can involve formatting, synonyms, or metadata while preserving the visible content. Each technique seeks to balance payload capacity, detectability, and robustness.

Applications include covert communication, digital watermarking for copyright protection, and data integrity auditing. Steganography can also be misused for malicious purposes, such as data exfiltration or covert command-and-control channels in malware.

Steganalysis is the field that studies methods to detect hidden data, while defenses include robust watermarking and techniques to minimize detectable artifacts in the carrier.