The RFC3161 (https://www.ietf.org/rfc/rfc3161.txt) specification states
3. Transports
There is no mandatory transport mechanism for TSA messages in this
document. The mechanisms described below are optional; additional
optional mechanisms may be defined in the future.
It lists a few examples such as
3.2. File Based Protocol
A file containing a time-stamp message MUST contain only the DER
encoding of one TSA message, i.e., there MUST be no extraneous header
or trailer information in the file. Such files can be used to
transport time stamp messages using for example, FTP.
A Time-Stamp Request SHOULD be contained in a file with file
extension .tsq (like Time-Stamp Query). A Time-Stamp Response
SHOULD be contained in a file with file extension .tsr (like
Time-Stamp Reply).
I would like to attach a timestamp token in PEM format (=base64 econded) to a document. What I wonder now is whether there are any already standardized header/footer lines for this? maybe such as
-----BEGIN TST-----
[...]
-----END TST-----
or
-----BEGIN RFC3161 TOKEN-----
[...]
-----BEGIN RFC3161 TOKEN-----
or should I just use default PKCS7 header/footer?