They require a "digital signature" for email requests, but say nothing about the format, nor any requirements for the signing key. You'd think that the NSA, of all organizations, would not put such technological naivete on public display.
Signed, /Michael Morisy/ Michael Morisy
For verification purposes,they ask for information like your SSN, place of birth, DOB, etc.
This generates a .p12 file rather than a typical .pem file to be shared.