Base64 encryption and decryption

The base64 encryption principle is as follows: 1. convert each character in the string to an octal number (the number of digits is not enough to add 0 at a high position, for example, if the binary number of A is '000000' and the value of 7 is changed to '000000', a long string of 1100001 is obtained by concatenating the binary number of each character. 2. then convert the 6-digit 6-digit number in this string into a 10-digit number, and then find the corresponding character in the following table, so that the encrypted string is obtained. 0 A 9 J 18 s 27 B 36 K 45 t 54 2 63/1 B 10 K 19 t 28 C 37 L 46 U 55 3 64 = 2 C 11 l 20 u 29 D 38 m 47 v 56 4 3 D 12 m 21 V 30 E 39 n 48 W 57 5 4 E 13 N 22 W 31 F 40 o 49x58 6 5 F 14 O 23x32G 41 P 50 y 59 7 6g 15 p 24 y 33 H 42 Q 51 Z 60 8 7 H 16 Q 25 Z 34 I 43 R 52 0 61 9 8 I 17 R 26 35 J 44 s 53 1 62 + (this may happen when processing the last 6 digits, if there are 2 or 4 digits left in the binary string, add 4 0 or 2 0 at the end to make up 6 digits, when adding four zeros, you must add two equal signs (=) to the last encrypted string and one equal sign (=) to the string. ') The opposite process is involved in decryption, so it is not described in detail. The following code implements base64 encryption and decryption in Java: Import Java. io. ioexception; <br/> import sun. misc. base64decoder; <br/> import sun. misc. base64encoder; <br/> public class base64coding {<br/> Private Static base64encoder encoder = new sun. misc. base64encoder (); <br/> Private Static base64decoder decoder = new sun. misc. base64decoder (); <br/> Public base64coding () {}< br/> Public static string encode (string s) {<br/> return encoder. encode (S. getbytes (); <br/>}< br/> Public static string decode (string s) {<br/> try {<br/> byte [] temp = decoder. decodebuffer (s); <br/> return new string (temp); <br/>} catch (ioexception IOE) {<br/> // handler <br/>}< br/> return S; <br/>}< br/>/** <br/> * @ Param ARGs <br/> */<br/> Public static void main (string [] ARGs) {<br/> string STR = "13516741234"; <br/> system. out. println ("encrypted"); <br/> system. out. println (base64coding. encode (STR); <br/> system. out. println ("decrypt"); <br/> system. out. println (base64coding. decode (base64coding. encode (STR); <br/>}< br/>}