Do you have to reset password with new hash?
Reset passwords for all users so they have to create a new password which will be hashed with the new hash function. Not the best idea, users will be unhappy and bothered, and will ask legitimate questions why you haven’t secured their passwords much earlier.
Is it possible to change the password hashing algorithm?
EDIT: The cryptography StackExchange has an interesting discussion on this method. Wait until your user logs in (so you have the password in plaintext), then hash it with the new algorithm & save it in your database. You probably can’t change the password hashing scheme now, unless you’re storing passwords in plain text.
Why are hashed passwords always the same password?
Hashed passwords are not unique to themselves due to the deterministic nature of hash function: when given the same input, the same output is always produced. If Alice and Bob both choose dontpwnme4 as a password, their hash would be the same: username. hash. alice.
What to do if you have a password hash in PHP?
If you had a database leak (which you’ve noticed) you need to reset passwords for all your users. Store their new passwords using the “new” hash then. If you’re using PHP then hash passwords with password_hash (…, PASSWORD_DEFAULT) and verify them with password_verify ().
What’s the fastest way to hash a password?
No matter if salted or not, or if stretched with several thousand iterations or just one function call. To store user passwords you should use one of these: bcrypt, Argon2 (the Argon2id or the Argon2i variant but only if you want password hashing to take more than one second, for anything faster use bcrypt), scrypt, or PBKDF 2.
How to transfer logins and passwords between instances?
Case-insensitive server A and case-sensitive server B: The sort order of server A may be case-insensitive, and the sort order of server B may be case-sensitive. In this case, users must type the passwords in all uppercase letters after you transfer the logins and the passwords to the instance on server B.