Base64 is an encoding scheme used for representing binary data in ASCII format using an alphabet of 64 characters. Although all implementations use the same first 62 characters (A-Z, a-z, and 0-9), the last two values may differ. The symbols + and / are used in the MIME specification. A base64 digit represents 6 bits of data, and four base64 digits encode exactly three bytes (8-bit) of binary data. When the number of digits is not divisible by three, extra bytes with a value of zero are added before converting to base64. Padding the encoded text with == or = can be used to indicate that the final group of three bytes from the plain data actually contained only one or two bytes.
Here is an example of encoding ...
