What are the four overall trust levels of eCH-0170, and which federation level does each one require?
1 no or minimal trust, 2 low trust, 3 substantial trust, 4 high trust; VSA, VSR and VSS run 1 to 4 in step, but the federation sub-model only has three levels: VSF1 for level 1, VSF2 for levels 2 and 3, VSF3 for level 4.
| Overall level | Name (German) | VSA | VSR | VSS | VSF |
|---|---|---|---|---|---|
| 1 | No or minimal trust (kein oder minimales Vertrauen) | 1 | 1 | 1 | 1 |
| 2 | Low trust (geringes Vertrauen) | 2 | 2 | 2 | 2 |
| 3 | Substantial trust (beträchtliches Vertrauen) | 3 | 3 | 3 | 2 |
| 4 | High trust (hohes Vertrauen) | 4 | 4 | 4 | 3 |
To reach an overall level, every sub-model must reach the value in that row (the weakest-link rule).
The federation column is the odd one out. Protecting an authentication confirmation in transit has fewer meaningful steps: signed; signed and kept confidential; signed, confidential and bound to its holder. So the confidentiality step (VSF2) serves both level 2 and level 3, and only level 4 demands holder-of-key binding (VSF3).