Cryptography is the practice of secure communication in the presence of third parties. Its modern history begins with the invention of public-key cryptography, which is used to secure communications between two parties who share a secret key. Public-key cryptography is also used for digital signatures, which are used to verify the identity of the sender of a message or document. Cryptography is also used in electronic voting, to protect data integrity, and in many other applications.
Cryptography is a mathematical science that uses mathematical algorithms to encode and decode data. These algorithms are designed to ensure that only authorized users can access the information and that the information cannot be altered by unauthorized users. Cryptography is used in a variety of applications, including email, file sharing, and secure communications.
Cryptography has been used for centuries to protect information from unauthorized access. The first known use of cryptography was by Julius Caesar, who used it to protect his military messages from enemy interception. In World War II, cryptography was used extensively by both sides in order to keep their war plans and strategies secret from their opponents. Today, cryptography is an essential part of computer security, especially in applications such as online banking and shopping where sensitive information must be protected from eavesdroppers and hackers.