bcrypt哈希密码可以转换为SHA2吗？

Question

I have two applications that use different ways to hash the users password. I want to syncronize these applications so that the user is allowed to login with the same user credentials.

Is it possible to convert a bcrypt password to SHA2?

Answer 1

Bcrypt and SHA-256 is a one-way hashing algorithm, you can't decrypt hashes (without brute-forcing). You cannot do a bulk password change. However, it is still possible to convert your database from one algorithm to another. Here's how:

1. Each time a user is logged into your website, compare if the supplied password matches the hash saved in your database.

2. If there is a match, then take the supplied password which would probably be in $_POST['password'] and then hash it to your destination algorithm like hash('mypassword', 'mypassword');

That's the only way you would be able to convert those hashed password.

In previous version of WordPress, they used to store passwords as hashed MD5. They have now introduced a new password algorithm and that how it works to convert old MD5 password hashes when you upgrade.