The issue of security is becoming increasingly important as civilization progresses into the information age (World Wide Web, transmission/distribution of digital multimedia data and more). In this article, we present the general concepts of a steganographic system, summarize our own steganographic research accomplishments during the past three years and propose a number of significant issues for future research on multimedia security systems (data hiding and authentication). In particular, we will discuss the following issues.

1. What is digital modern steganography/steganalysis?

2. Why, and who needs steganography/steganalysis?

3. What are the uses for steganography/steganalysis?

4. What are the differences among steganography, cryptography, and watermarking?

5. How can information be undetectably hidden?

6. How is a good cover medium for a given stego message chosen?

7. How does one detect a stego message?