问题
I have a vBulletin Database with double MD5'd passwords and a salt, would it be possible to take the Password in the vBulletin database, convert them to SHA256, and then store them in a new database? Is there any real easy way to do this?
My main and only reason, is to prevent users from having to create new accounts, and to stop using MD5.
回答1:
Hashing algorithms are one-way i.e. They cannot be reversed unlike Encryption-Decryption algorithms.
MD5() is a hashing algorithm , so is SHA-1 / SHA-256;
It is good to know that you have stopped using MD5() and moving to SHA-256()
Solution to your problem.
First run a query in your users table like this
UPDATE users_t SET PASSWORD=SHA2(PASSWORD,256) WHERE 1=1
Now all your MD5 Hashed passwords will be converted to SHA256 Hashes.
However, you cannot stop using MD5 on your login/register pages.. You have to change your checking logic like
$pass = $_POST['password'];
$hashedpass = hash('sha256',md5($pass)); // Now you need to insert/verify
来源：https://stackoverflow.com/questions/19486947/possible-to-convert-md5-to-sha256