Cryptography is the science of using mathematics to protect data. It enables the user to store sensitive information or transmit it across insecure networks (like the Internet) so that it cannot be read by anyone except the intended recipient. There are several objectives related to cryptography: confidentiality is a service used to keep the content of information from all but those authorized to have it; data integrity is a service which addresses the unauthorized alteration of data, having the ability to detect data manipulation by unauthorized parties; and authentication is a service related to identification which applies to both the entities and the information itself.