Information Hiding with a Handwritten Message in Vector-drawing Codes † Tohoku University (postgraduate student) Aramaki aza Aoba 04, Aoba-ku Sendai-city Miyagi-pref.980-8579, Japan Figure 1. message board (client). Figure 2. input devices (pen tablet and mouse) ABSTRACT The Internet has been evolving exponentially those two decades, and various types of commu- nication systems for computer supported coop- erative work (CSCW) are available throughout networks. Some of those systems provide hand- writing functions, and handwritten messages are used often for authentication. In other com- munication systems, however, one needs infor- mation hiding. A requirement of a communica- tion system is to provide a subliminal channel for secret communications. This paper presents some new algorithms for information hiding with a handwritten message which is encoded with vector drawing. KEYWORDS information hiding , handwriting function, vec- tor drawing, signature 1. MOTIVATION Since the Internet provides people with a global connectivity, various communication system are available as groupware [1] for CSCW [2]. Some of those systems have a function for an ex- change of handwritten information. For in- stance, we have brought a message board on a door of a room in a student hall of residence into the network environment [3, 4] (Figure 1). It is a whiteboard-like message board system on WWW for asynchronous communication, which provides users with simple tools for drawing. On this board, any message can be written by hand, making use of a mouse and a Norihisa Segawa † Iwate Prefectural University 152-52,Takizawa-aza-sugo, Takizawa, Iwate,020-0193, Japan +81-19-694-2674 sega@iwate-pu.ac.jp Yuko Murayama Iwate Prefectural University 152-52,Takizawa-aza-sugo, Takizawa, Iwate,020-0193, Japan +81-19-694-2548 murayama@iwate-pu.ac.jp Masatoshi Miyazaki Iwate Prefectural University 152-52,Takizawa-aza-sugo, Takizawa, Iwate,020-0193, Japan +81-19-694-2618 miyazaki@iwate-pu.ac.jp pen tablet (Figure 2). Letter of messages is coded as a collection of lines. We call this type of communication "on-door communication," and implemented a prototype system. A handwriting has the following features [3]: (1) it is suitable for leaveing a short note (2) a text and a picture are drawn on the same space without working about language codes. Proceedings of the 35th Hawaii International Conference on System Sciences - 2002 0-7695-1435-9/02 $17.00 (c) 2002 IEEE 1