As we saw in the previous example, security labels are a set of tokens the user chooses to use. The tokens are a set of ASCII characters (arbitrary strings). In the previous example, we used the logical AND operator to join two authorization tokens.
Examples of usage are:
SecTokenA&SecTokenB, where the user needs both
SecTokenBto be able to see the cell
SecTokenA|SecTokenB, where the user only needs one token,
SecTokenB, to be able to see the cell
(SecTokenA&SecTokenB)|SecTokenC, where the user only needs either
More complex rules can be created using Boolean
|) combinations. ...