Genuine question: what's your thread model?
Vault gives time limited Tokens with Network Boundary. Instead of Keeper, i would just use age:
# write
echo "my secret" | age -r <recipient-pubkey> > secret.age
# read
age -d -i key.txt secret.age
Vault gives time limited Tokens with Network Boundary. Instead of Keeper, i would just use age:
# write
echo "my secret" | age -r <recipient-pubkey> > secret.age
# read
age -d -i key.txt secret.age
This is an age+filesystem secrets manager that I made that is basically what you wrote, but with more organization.