Signatures may be stylish or unconventional and have many personal characteristics that are challenging to reproduce by anyone other then the original author For this reason signatures are used and accepted as proof of authorship or consent on personal checks credit purchases and legal documents Currently signatures are veri ed only informally in many environments but the rapid development of c...

Today, the characterization of the technological age is done by the digital images spread. They are the most common form of conveying information whether through internet, newspapers, magazines, or scientific journals. They are used as a strong proof of various crimes and as evidence used for various purposes. The modification, capturing or creating of the image has become easier and available ...

Thanks to the availability of many sophisticated image processing tools, digital image forgery is prevalent nowadays. One of the common methods is copymove forgery (CMF), where part of an image is copied to another location in the same image. Detection of copy-move forgery has been widely researched recently, and many different solutions have been proposed. This chapter introduces a different a...

MAC striping has been suggested as a technique to authenticate encrypted payloads using short tags. For an idealized MAC scheme, the probability of a selective forgery has been estimated as ( `+m m )−1 ·2−m, when utilizing MAC striping with `-bit payloads and m-bit tags. We show that this estimate is too optimistic. For m ≤ ` and any payload, we achieve a selective forgery with probability ≥ ( ...

We first give an analysis on Zhang et al.’s attack on a short signature scheme so called ZCSM scheme and point out their forgery attack is not correct one. Furthermore, we present a forgery attack under the chosen message and public key attacks on ZCSM scheme, in the sense of Zhang et al.’s attack. We also analyze Zhang et al.’s improved signature scheme suggested to resist their attacks and po...

As a useful means of safeguarding privacy of communications, deniable authentication has received much attention. A Chameleon-based deniable authenticated key agreement protocol is presented in this paper. The protocol has following properties. Any one of the two participants can’t present a digital proof to convince a third party that a claimed agreement has really taken place. Once a forgery ...

Detection of image forgery is always a crucial factor in image forensic and security applications. Usually this detection is possible with the help of local or global features of an image. We can ensure the credibility of an image with a hashing method by fusing local and global features together. So that it is possible to detect even sensitive image forgeries. Here, we are proposing an improve...

In this paper we propose a universal forgery attack of Hess’s second IDbased signature scheme against the known-message attack.