1. A method for managing security credentials in a system of at least one computer, the system having a credential checking facility to authenticate one or more principals, the method comprising the steps of: in a first directory context, providing a principal with a secure package containing a credential; in a second directory context, receiving a request from the principal to access the system; enabling the credential checking facility to check the access request by accessing the credential in the secure package; allowing or denying the access request according to the result of the credential check; and determining whether credential information about the principal which is found in the second directory context was not placed in the secure package in the first directory context.