Abstract: This paper focuses on the applications of multimedia information processing technology in the field of physical space security．In this article, the development of speech, image and video information hiding technology, digital watermarking technology, information source identification technology and the multimedia forensics technology are introduced in detail. And the intercrossed applications and development trends of multimedia technologies in information security areas.

Key words: multimedia security, physical space security, information hiding, speech recognition, multimedia forensics

摘要： 聚焦于以各种多媒体形式为载体的信息处理技术在物理空间信息安全中的应用，阐述了语音、图像和视频相关的信息隐藏技术、数字水印技术、信息源识别技术以及多媒体取证技术等在安全领域的应用和发展现状，并对各种多媒体处理技术在信息安全领域的交叉应用和发展趋势进行了详细讨论.

关键词: 多媒体信息安全, 物理空间安全, 信息隐藏, 语音识别, 多媒体取证