Bitcoin is a new kind of money, which means a digital currency which can be used for commercial purposes. Over time, the trade has evolved from barter to the use of the precious metals as money, then to the coins with intrinsic value and to the symbol coins and later to the use of the electronic...

It is widely recognized that the public-key cryptosystems are playing tremendously an important role for providing the security services. In majority of the cryptosystems the crucial arithmetic operation is modular exponentiation. It is composed of a series of modular multiplications. Hence, the...

Protection of digital images from malicious (and dishonest) insider entities is an important concern in modern digital space. A malicious entity can alter some important features of an image to mislead the target recipient of the image, which can cause harm in applications such as healthcare,...