As you know, Wordpress db has a wp_users
table where there is a user_pass
field.
Is it possible that two or more different users have exactly the same user_pass
value in that field?
Theoretically No! But practically Yes!
Every new framework/CMS now implements some sort of library that adds randomness to the actual password. Its a randomly generated salt in form of a random string or time, etc. That is saved along with the hash password in database.
Since theoretically, a collision can occur in any cryptographic function so User passwords may not be considered unique. But practically we know that even for a simple md5 hash algorithm we need to hash about 2^64 values to get a single collision on average.
So practically its impossible to ever see two users with same password.
user_pass
is not a unique column, so technically the same value could be in there twice, but whatever hashing is done seems to involve some randomness or incorporates the current time, because I added a couple of users with the same password but the password hash was different.