Overview

Base64 Encoding Instructions

Base64 encoding requires that 3 8-bit bytes (3*8=24) be converted into 4 6-bit bytes (4*6=24), and then two 0s are added in front of the 6 bits to form an 8-bit word The form of the section. If the remaining characters are less than 3 bytes, fill it with 0, and use'=' for the output character, so 1 or 2'=' may appear at the end of the output text after encoding.

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

Base64 Encoding Table

Code Character   Code Character   Code Character   Code Character
0 A 16 Q 32 g 48 w
1 B 17 R 33 h 49 x
2 C 18 S 34 i 50 y
3 D 19 T 35 j 51 z
4 E 20 U 36 k 52 0
5 F 21 V 37 l 53 1
6 G 22 W 38 m 54 2
7 H 23 X 39 n 55 3
8 I 24 Y 40 o 56 4
9 J 25 Z 41 p 57 5
10 K 26 a 42 q 58 6
11 L 27 b 43 r 59 7
12 M 28 c 44 s 60 8
13 N 29 d 45 t 61 9
14 O 30 e 46 u 62 +
15 P 31 f 47 v 63 /