PHP BASE64 encoding/decoding

First, how to use PHP

// Encrypt $str = ' This was an encoded string '; Echo Base64_encode ($str); // decryption $str = ' vghpcybpcybhbiblbmnvzgvkihn0cmluzw== '; Echo Base64_decode ($str);

Second, Base64 code description
1. BASE64 encoding requires 3 8-bit bytes (3*8=24) to be converted to 4 6-bit bytes (4*6=24), followed by 6 two in front of 0 bits, forming a 8-bit byte form. If the remaining characters are less than 3 bytes, then 0 is populated with the output character using ' = ', so there may be 1 or 2 ' = ' At the end of the encoded text output.

2, in order to ensure the output of the encoded bit readable characters, BASE64 developed an encoding table for unified conversion. The size of the encoded table is 2^6=64, which is also the origin of the Base64 name.

Three, BASE64 encoding table

PHP BASE64 encoding/decoding