Formerly reserved for military uses, cryptographic tools continue to experience major changes. With the main objective of providing better data security, cryptography encrypts data in order to make them incomprehensible. To make them readable, the use of another similar key was necessary. And yet, faced with the deployment of a large number of keys, logistical problems were observed and led to a slowdown in the speed of exchanges.
Today, thanks to the use of the Internet in many sectors of daily life but also to the development of electronic exchanges, the principle of the two American mathematicians Diffie and Hellman is still enjoying real success.
Also called asymmetric cryptography, this method actually uses two keys including a public key which can be freely distributed as well as a secret key which is known only to the recipient alone.
Generally speaking, public key cryptography uses a public directory where only the public key is revealed there while the private key for decryption is kept secret. To prevent an unauthorized person from using their own key, each key in the directory is accompanied by an authentication certificate which can only be issued by an independent authority.
The advantages of public key cryptography
The use of public key cryptography provides many advantages, the most important of which is the ease of management of the pool of keys it offers. Indeed, even if many users wish to use the system, no particular modification will be made to the parameters.
For each user group, they will simply be asked to choose an administrator who will be responsible for managing the keys. Then, each person concerned will have to register with this administrator who will administer to each a pair of keys, one of which is private and one public. The administrator will then be responsible for secretly informing each user of the private key code. Finally, all that remains is to publish all the public keys in a directory.
Thus allowing messages to be exchanged in a secure manner and without the need for security devices, public key cryptography therefore solves the problems of key distribution.
For the sender of a message and the recipient, the need to share secret keys from a secure channel is no longer required as all communications only require the use of public keys while the keys private are kept confidential.