Base64 encoding is a binary-to-text encoding scheme that represents binary data in an ASCII string format by translating it into a radix-64 representation. This encoding method is commonly used in web applications to send binary data over HTTP and is often used to embed image or audio files in HTML or CSS files as text.

Base64 works by converting binary data into a string of ASCII characters. This is achieved by using a table of 64 characters that consists of the upper- and lower-case letters, the digits 0-9, and the symbols '+' and '/'. Each group of three bytes from the binary data is split into four characters from the Base64 table. The result is a string representation of the original binary data.

Base64 encoding is used in web because it provides a way to transmit binary data in a text format that is compatible with most systems and protocols. This allows binary data to be sent over HTTP without the need for a separate binary transfer protocol. Additionally, encoding binary data in Base64 format can be useful for reducing the size of the data being transmitted.

Base64 was created by Robert T. Morris and Joan Daemen in the early 1990s as a way to represent binary data in an ASCII string format. It was later standardized by the Internet Engineering Task Force (IETF) in their Request for Comments (RFC) 2045, which defined the Base64 encoding scheme for encoding binary data in MIME (Multipurpose Internet Mail Extensions).