Digital Signatures Discussion
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VII.
Signing a CDA
a. Signature text element applied to legal authenticator and
authenticator occurrences
b. Within signature you can declare
i. Role of signature
ii. Purpose of signature
c. Signatures are independent of each other, others can also digitally
sign the document
d. Signature is bound to entries in the header
e. Once you break a document up the signatures will not persist
Within the context of CDA and its limitations, within the context of the ability
to sign things at a smaller level those are not possible in most EHRs
a. Solution is to take CDA at point of attestation or authorship
b. Provenance can clearly separate those things that individuals author
Legally authenticated in a CDA without a legal authenticator means the CDA
has been flagged
a. Concept of legal authentication in CDA is a CDA construct, whether it
has reality in business/legal setting is a separate issue
Is there any reason why an EHR signature event cant sign multiple artifacts
at the same time?
a. If you have something that has been signed, and it needs to be
incorporated into something else, given the current approach, the
signature will not move with it. There must be a new attestation
b. The main scenario we have to deal with is when the end user is
already known (medicare has specifications for competence to work
with their system). The system knows that an end user is CMS – when
the artifacts is signed you are signing a doc that meets specifications
for CMS end use. This will meet majority of use cases
i. For cases where end user is not known, you will authenticate
an object with the minimum necessary requirements for that
object.
What if a previously signed object is later forwarded?
i. Original object is signed to local requirements.
ii. Once CMS requests it, you can attest the object as a previously
signed object.
b. Why does a system need to treat a ceremonial event the same as the
paper world signing one and only one object?
Consider looking at the ability of a system to keep track of authors and if the
object was authenticated
Options
a. Can signed and attest to authorship
b. Can sign and not attest to authorship
c. Take these options and decide where are we going
i. Granular level with persistent signatures
1. CDA cannot solve this.. need to look at other options
(FHIR?)