An identity that echoes checksum entries — the anonymous identity and the
viewer; the tokens-only identity is the one that does not — with the pair the
server served it. The only carrier of the checksums, and it carries nothing
else of the identity's auth: the serializer writes the tokens and the viewer
from the batch of the same kind, so they have one writable copy (a checksum
entry never carries the hmac_ttl token).
An identity that echoes checksum entries — the anonymous identity and the viewer; the tokens-only identity is the one that does not — with the pair the server served it. The only carrier of the checksums, and it carries nothing else of the identity's auth: the serializer writes the tokens and the viewer from the batch of the same kind, so they have one writable copy (a checksum entry never carries the
hmac_ttltoken).