NOTE: the password specified by the -p option of useradd must already be encrypted...
-p, --password PASSWORD
The encrypted password, as returned by crypt(3). The default is to
disable the password.
Note: This option is not recommended because the password (or
encrypted password) will be visible by users listing the processes.
You should make sure the password respects the system's password
And note that the "crypt(3)" is for DES passwords only, and is insecure. It is much better to use the passwd utility.