The invisible inks have many applications, including the use of banknote printing, code load, securitydocuments and much of its application in the exchange of security information. Photoluminescenceproperties of lanthanide compounds that attracted the attention of many scholars in recent decades are one ofthe important factors in drying and fluidity of the ink. The solvent eva...

Stimuli-responsive photoluminescent (PL) materials have been widely used as fluorescent ink for data security applications. However, traditional fluorescent inks are limited in maintaining the secrecy of information because the inks are usually visible by naked eyes either under ambient light or UV-light illumination. Here, we introduced metal-free water-soluble graphitic carbon nitride quantum...

Since ancient times, steganography, the art of concealing information, has largely relied on secret inks as a tool for hiding messages. However, as the methods for detecting these inks improved, the use of simple and accessible chemicals as a means to secure communication was practically abolished. Here, we describe a method that enables one to conceal multiple different messages within the emi...

Finding the outperforming photoactive charge trapping materials for a new-trending transistor photomemory application is labor intensive, costly reagents and solvents, not to mention, inefficient energy time consumption. In this work, costless organic-based inks are introduced as novel storage material that inspired by high fluorescent ink of cheap invisible pens when exposed ultraviolet light....

Steganography, derived from Greek, literally means “covered writing”. It includes a vast array of secret communications methods that conceal the message’s very existence. These methods include invisible inks, microdots, character arrangement, digital signatures, covert channels, and spread spectrum communications. This paper proposes a new improved version of Least Significant Bit (LSB) method....

The purpose of this tutorial is to present an overview of various information hiding techniques. A brief history of steganography is provided along with techniques that were used to hide information. Text, image and audio based information hiding techniques are discussed. This paper also provides a basic introduction to digital watermarking. 1. History of Information Hiding The idea of communic...