Role and O-set names in ABAC are allowed to contain the following sets of 
characters:

    A-Z
    a-z
    0-9
    -       [hyphen]
    _       [underscore]

A name must begin with a lower case letter (a-z)

There is no limit on the length of a name.

As a technicality, creddy requires the CN to also meet these rules. Both ABAC
and creddy will handle certificates with CNs that do not meet this criteria.