Koichi Kamijo

Secure digital photograph handling with watermarking technique in insurance claim process

This paper presents a secure method to handle digital photographs in insurance claim process. It consists of: Device authentication by secure protocol capable to protect photographs from substitution, Watermarking technique to embed digital signatures on JPEG data and detect altered portions, and Robust watermarking technique to embed image identification number which persists throughout decompression/compression operations. The device authentication is used in transmissions of photograph images from a digital camera (DC) to a compact flash memory (CF), and from a CF to a personal computer (PC). Thus images are authenticated at the one-way pass of DC, CF and PC. In registering images on PC, an image identification number and a digital signature are embedded into a JPEG data stream by a watermarking technique called DataHidingTM. We could imbed 96 bits of data into a 640 X 480 pixel image without degrading visual image quality and persistency of embedding data. After the watermarking process, a photograph can be identified by decoding an embedded number and detected any altered portion by an embedded signature. Using the new method, we have developed a prototype secure claim process, and verified the feasibility of the method at field trials.

Optimizing watermarking to improve the robustness without affecting the fidelity

One of the expected application areas for the practical use of the watermarking technology is for protecting contents from illegal distribution and/or copying, such as for DVD copy protection. In such application areas, the watermarked contents should be robust with regards to various kinds of post-processing, such as digital-to-analog or analog-to-digital (D/A, A/D) conversion, MPEG compression, and VHS recording. This paper introduces a watermark embedding method that maximizes the strength of the detected watermark signal, an embedding method robust against MPEG compression, and an embedding method robust against VHS recording, without affecting the fidelity of the watermarked contents.

Anonymity-Aware Face-to-Face Mobile Payment

On-line payments are increasingly popular in paying bills for Internet shopping, and payment-capable mobile phones support making purchases anytime and anywhere, without cash. However, mobile payments are rarely used for making face-to-face payments, with concerns about anonymity, security, and usability. This paper proposes a face-to-face mobile payment protocol that addresses these concerns. To address anonymity and security concerns, the proposed protocol uses unique information for the payment transaction, such as the location and the time, and introduces two procedures for optimizing the matching time slots and exchanging random numbers when needed, to secure the transactions without exposing the seller’s or the buyer’s personal identification. To address usability concerns, the proposed protocol optimizes the parameters for the two introduced procedures to match the seller-buyer pairs, depending on the number of the people involved in the mobile payments, the delays caused by human operations with the mobile phones, mobile communication, and so on. Experimental results prove that the proposed protocol is practical, solving the addressed concerns.

An invisible hyperlink marker

In this paper, we propose an invisible hyperlink marker, by which users can easily get information related to articles in paper media, similar to hyperlinks in the Web. Users get information using a device such as a mobile phone by illuminating the marker with a blacklight and taking its photo. A new skipbit coding method makes it possible to embed information even in articles that absorb or repel the invisible ink. Experimental results proved that information can be extracted from the markers printed on top of materials such as newspapers and brochures in about one second using a prototype mobile phone.