Review of the use of human senses and capabilities in cryptography

Cryptography is a key element in establishing trust and enabling services in the digital world. Currently, cryptography is realized with mathematical operations and represented in ways that are not readily accessible to human users. Thus, humans are left out of the loop when establishing trust and security in the digital world. In many areas the interaction between users and machines is being made more and more seamless and user-friendly, but cryptography has not really enjoyed such development. In this paper, we review the previous research on utilizing human senses and capabilities in cryptography. We present the most relevant existing methods and summarize the current state of the art. In addition, we propose several topics and problems that need to be solved in order to build cryptography that is more accessible to humans. These range from practical implementations of existing methods and utilizing a wider range of human senses all the way to building the theoretical foundations for this new form of cryptography.