Because of the still evolving, and sometimes conflicting, terminologies used in the fields of computer science, computer security, and cryptography, the term "digital credential" is used quite confusingly in these fields. Sometimes passwords or other means of authentication are referred to as credentials. In operating system design, credentials are the properties of a process (such as its effective UID) that is used for determining its access rights. On other occasions, certificates and associated key material such as those stored in PKCS#12 and PKCS#15 are referred to as credentials.