The password itself is not stored in AD in decryptable form. As I understand it what is stored is a hash of the password and the date/time when the password was set. When a user logging on enters the password that value and the date/time when the password was last set are used to re-calculate the stored hash. if this is the same as the stored hash, the assumption is that the user entered a valid password.
Full Definition of CREDENTIAL. 1. : something that gives a title to credit or confidence; also: qualification 3a. 2. plural: testimonials or certified documents showing that a person is entitled to credit or has a right to exercise official power.
Full Definition of CERTIFICATE. 1. : a document containing a certified statement especially as to the truth of something; specifically: a document certifying that one has fulfilled the requirements of and may practice in a field. 2.: something serving the same end as a certificate.3.efinition of CERTIFICATE for Kids. 1. : a written or printed statement that is proof of some fact. 2. : a paper showing that a person has met certain requirements. 3. : a paper showing ownership.