Encoding has a number of applications. Foremost is the preservation of privacy or the transmission of sensitive information, for example financial records or military communication. This type of encoding is often refereed to as encryption. However, there are many uses and purposes of encoding. One category of encoding is the mapping of one symbol to another, for example the number 65 to the letter A. Computers use this type of code (ASCII) to store letters in memory. Other encodings facilitate the transmission of text over the internet. The terms character encoding, character map, character set, or code page are historically synonymous.
Compression algorithms use encoding to reduce the size of readable text. Error correcting algorithms encode the message in such a way that if part of the message is corrupted, the error can be detected and the original message can be recovered.