Definitions

Personally Identifiable Information (PII)
OMB has defined the term Personally Identifiable Information (PII) as “any information about an individual maintained by an agency, including, but not limited to, education, financial transactions, medical history, and criminal or employment history and information which can be used to distinguish or trace an individual’s identity, such as their name, social security number, date and place of birth, mother’s maiden name, biometric records, etc., including any other personal information which is linked or linkable to an individual.”
Sensitive But Unclassified (SBU) Information
SBU information is any information which the loss, misuse, or unauthorized access to or modification of could adversely affect the national interest or the conduct of Federal programs, or the privacy to which individuals are entitled under Title 5 U.S.C. Section 552a, but which has not been specifically authorized under criteria established by an Executive Order or an Act of Congress to be kept secret in the interest of the national defense or foreign policy.
Encrypt
To alter a file using a secret code so as to be unintelligible to unauthorized parties.
Security Breach
OMB has defined a security breach as follows: "The term breach is used to include the loss of control, compromise, unauthorized disclosure, unauthorized acquisition, unauthorized access, or any similar term referring to situations where persons other than authorized users and for an authorized purpose have access or potential access to personally identifiable information in usable form, whether physical or electronic."