Steganography is the practice of hiding a secret message within an ordinary-looking carrier—an image, audio file, or video—so that no one even suspects a message exists. Unlike encryption, which scrambles data into obvious ciphertext, steganography hides the existence of communication itself.
How Does Image Steganography Work?
Most image steganography techniques modify the least-significant bits (LSBs) of pixel values, or in the case of JPEG images, the quantized DCT coefficients. The changes are so small that the human eye cannot detect them, and the image looks identical to the original.
Steganography vs. Encryption
Encryption and steganography are complementary. Encryption protects the content of a message (if intercepted, it can't be read). Steganography protects the existence of the message (it's never noticed in the first place). The strongest approach uses both: encrypt the message, then hide it steganographically.
Modern Steganography Techniques
Modern steganographic algorithms like J-UNIWARD and UERD are designed to minimize statistical distortion, making them resistant to machine-learning-based steganalysis. They analyze the image content and embed data where changes are least detectable—in textured, noisy regions rather than smooth areas.
Where Is Steganography Used?
- Journalism: Protecting sources and sensitive communications
- Activism: Communicating in censored environments
- Personal privacy: Sharing secrets without drawing attention
- Digital watermarking: Embedding ownership information in media
Try It Yourself
Phasm makes steganography accessible to everyone. With two modes—Ghost for stealth and Armor for robustness—you can hide messages in JPEG photos with military-grade encryption, entirely on your device.