We can provide something better than a flat string mapping. Some thoughts on requirements:

• Require that a minimum set of keys are present, else return null
• Allow piecewise assembly of principal names with the following components:
  • Static string
  • Single attribute value e.g. dc[0]
  • Joined attribute value (with optional subrange) e.g. dc:"." would convert dc=example,dc=com to example.com
  • Joined attribute value in reverse (with optional subrange)