手机水印相机程序拍摄照片的真实性鉴定

Forensic Authentication of Images Imposed by Watermarking Camera Programs Built in Mobile Phones

随着声学和光学传感器技术的快速发展及其在手机等移动智能设备上的广泛应用,传统的基于元数据分析、成像分析、处理痕迹分析、图像信号分析等技术手段的图像真实性鉴定已形成相对成熟的综合鉴定方案,然而,针对手机中个性化相机程序拍摄照片的真实性鉴定问题,仍缺乏系统的技术研究和方法指导。本文系统研究手机水印相机程序拍摄照片的图像数据特点,并以市面上流行的两款水印相机为例详细研究手机水印相机程序拍摄照片的真实性鉴定的检验内容和鉴定方法。研究结果表明,文件属性和元数据信息检验在解决上述问题中发挥着重要作用,但又与传统的检验内容存在差异。检验过程中,应充分关注手机操作系统特性以及水印相机程序特性以实现客观科学的个性化相机程序拍摄图像的真实性鉴定。

Mobile smart devices,e.g.,the mobile phones,are always built with the acoustic and optical sensors representing their rapid developing and wide applying mainstream technologies so that the relevant image authentication has got to comparatively mature and comprehensive solutions about those involving metadata,imaging artifices,processing signs and image signals.However,the ever-personalized camera programs are available and popular in mobile phones,bringing in problems occurring for forensic authentication of images taken under related handling.Here,forensic authentication was put into the images imposed by watermarking camera programs set up with mobile phones.Two popular watermarking camera programs(developed by Shanghaibased Tencent Technology Co.,Ltd.and Beijing Xiaohei Technology Co.,Ltd.)were used to explore the feasible examination materials and methods for the purpsoe of forensic authentication.Through scrutiny into the features of the original images imposed by watermarking cameras and the conditions of watermarking,an exampling case was carried out on how to undertake the concrete examination process of such the kind of forensic image authentication and have the effectiveness verified.Evidently,the file attributes and metadata information did play an important role for such an authentication although some differences were present from the traditional examination materials.For example,the“Photoshop”information in the metadata of images hints the existence of editing operation traditionally,yet being taken as a normal phenomenon and reasonable presence for the images imposed by watermarking camera programs.Therefore,in order to achieve the objective and scientifi c opinions with examination,much attention should be paid to the characteristics of mobile phones’operating systems and watermarking camera programs,the two key materials for forensic authentication of images imposed by personalized camera programs built in mobile phones.