The document discusses various principles and methods of access control, including: 1) Three main principles of access control are identity, authority, and accountability. Identity establishes a user's identity, authority authorizes access privileges, and accountability tracks user actions. 2) Common methods to establish identity include passwords, tokens, biometrics, and digital certificates. Multifactor authentication combines multiple methods for stronger security. 3) Access control models like Bell-LaPadula and Biba are used to enforce security policies based on confidentiality, integrity, and transactions. Clark-Wilson defines processes to control access to critical data items.