Base64 encoding is a method of representing binary data as ASCII text. It's commonly used for encoding data in a way that can be easily transmitted over text-based protocols, such as email or web services, and stored in text-based file formats, such as XML or JSON.
In Base64 encoding, binary data is divided into groups of 6 bits, and each group of 6 bits is mapped to a unique 64-character alphabet. This alphabet consists of the upper- and lowercase letters A-Z, the digits 0-9, and two special characters: + and /. The = character is used as a padding character to ensure that the last group of 6 bits has a length of 4 bits.
To encode data in Base64, the binary data is first divided into groups of 6 bits, and each group is then mapped to a unique character in the 64-character alphabet. The resulting string of characters is the Base64 encoded representation of the original binary data.
To decode Base64 encoded data, the reverse process is followed. The Base64 encoded string is first divided into 4-bit groups, and each group is then mapped back to its original 6-bit binary representation. The resulting binary data is the decoded representation of the original Base64 encoded string.
Base64 encoding is widely used for encoding binary data in a way that is easily transmitted over text-based protocols and stored in text-based file formats. It's also commonly used for encoding authentication credentials, such as username and password, in HTTP Basic Authentication headers.