Some architecture/policy issues
Are we worrying about access to stored data, or eavesdropping on communication channels, or both?
Where do keys come from? Who generates them?
Do we treat signature keys differently from encryption keys?
Who can be an authorized escrowed agent? Can people escrow their own keys?
Who has liability if escrowed keys are compromised?
What are the legal standards for getting access to escrowed keys?
Why should people use these systems? (E.g., regulations, legal sanctions, tax incentives, liability incentives, … .)