OpenSSL does not natively support using USB keys. Although OpenSSL does
have APIs for loading certificate data from memory, Indy does not expose
that functionality yet. So at this time, you can only load certificate
files from disk. If the USB key has a drive letter assigned to it, and
contains certificate files in PEM or ASN.1 format, you can try pointing
Indy directly to the USB key's files, otherwise you are basically SOL.