ord, md5 shows different behaviour on @

问题

I used ord to check @ and @‪ are same char. But ord output the same value while md5 does not.

php -a
Interactive shell

php > echo ord('@');
64
php > echo ord('@‪');
64

php > echo md5('@');
518ed29525738cebdac49c49e60ea9d3
php > echo md5('@‪');
e6124653b6620abe51d7c401a7644674
php >

Here is the screenshot,

回答1:

Your second one is @ followed by U+202A - LEFT-TO-RIGHT EMBEDDING. As they are different strings, naturally they have different MD5 encodings.

php > echo md5("@\u{202a}");
e6124653b6620abe51d7c401a7644674

来源：https://stackoverflow.com/questions/58010681/ord-md5-shows-different-behaviour-on