Base64 Encoding Instructions

Base64 encoding requires converting 3 8-bit bytes (3*8 = 24) into 4 6-bit bytes (4*6 = 24), and then adding two 0s in front of the 6-bit to form an 8-bit byte. If the remaining characters are less than 3 bytes, they are padded with 0s, and the output character uses '=', so 1 or 2 '=' may appear at the end of the encoded output text.

In order to ensure that the encoded bits output are readable characters, Base64 has developed an encoding table for unified conversion. The size of the encoding table is 2^6 = 64, which is also the origin of the name Base64.

Base64 Encoding Table