Cryptography

2 Introduction to Cryptography

For millennia, human beings used multiple forms of cryptographic codes to protect their oral communications, entries of castles, their messages (in particular between armies and their commanders), their money, etc. Therefore, cryptography had existed very early in human history and civilizations, before the advent of computers.

Since the early times, Human beings were in need to communicate, share information, and communicate selectively. These two needs gave rise to the art of message coding (i.e. encrypting) in such a way that only the intended people could have access to the information.

Cryptography has been developed and improved over centuries; in particular for military and defense reasons (protection of military secrets and spying of enemies), then for industrial reasons (protection of industrial secrets), afterward for securing the recent applications made possible thanks to the internet (e-banking, e-commerce, bitcoins, …), and ultimately for protecting the privacy of electronic devices’ users.

In modern digitalized society, cryptography is the pillar of security. Cryptography is used to protect data while in transit over unsecure channels and data on storage devices (i.e. USB devices, disks, etc.). Encryption is everywhere in the cyberspace. Encrypting and signing are the most performed cryptographic operations. Cryptography secures websites and makes electronic transmissions safe. In particular, public-key cryptography enables people ...