
I want my passwords to be secure in database. Even if someone leaks the passwords I don't want anyone to be able to decrypt them.

I want my passwords to be secure in database. Even if someone leaks the passwords I don't want anyone to be able to decrypt them.
Passwords are hashed, not encrypted. There is a big difference. You must understand that encrypted strings can be retrieved by decrypting them. This is not possible when hashing. Hashes are, most of the time, not reversible and passwords are checked by matching the hashes. Hash methods such as MD5 have been cracked and are therefore not safe anymore as the password can be "unhashed".
You should not attempt to make your own hashing algorithm as it will most likely have major security flaws. Current day algorithms have been developed by countless of security and cryptography experts and have been analyzed over and over again. There is just a zero percent chance that your backyard algorithm will be more secure than algorithms developed by experts.
Just use the PHP default methods which are password_hash and password_verify.
The hashing function generates a random salt by itself which is appended to the hashed password. It is therefore a very safe method and your best bet.