* For how long must it be secure?
let's say for 10 years
* Against whom must it be secured?
Everyone, including national agencies and organised crime.
* What are your potential losses if it's broken?
A lot of money.
* How can you be sure you've used a secure implementation?
No idea
* What do you think the "strongest available crypto" currently is?
No idea, but I would guess someone has this answer
* Can you be sure that the key will never be compromised?
No, but this is a separate problem, I assume here that the key is not compromised.
* Where will you store the key?
Off-line
* Do you need to send the key to someone else?
No.
* Where will the encryption happen?
Locally.
* Against whom must it be secured? Everyone, including national agencies and organised crime.
* What are your potential losses if it's broken? A lot of money.
* How can you be sure you've used a secure implementation? No idea
* What do you think the "strongest available crypto" currently is? No idea, but I would guess someone has this answer
* Can you be sure that the key will never be compromised? No, but this is a separate problem, I assume here that the key is not compromised.
* Where will you store the key? Off-line
* Do you need to send the key to someone else? No.
* Where will the encryption happen? Locally.