## Union of http://smart.who.int/trust/CodeSystem/KeyUsage and http://smart.who.int/trust/CodeSystem/KeyUsage

This is the CodeSystem that contains all the codes in WHO GDHCN Key Usage CodeSystem (http://smart.who.int/trust/CodeSystem/KeyUsage) and WHO GDHCN Key Usage CodeSystem (http://smart.who.int/trust/CodeSystem/KeyUsage). E.g. what you have to deal with if you get resources containing codes in either of them

### CodeSystem

Generated Narrative: CodeSystem eb76ae3b-21b6-4ae4-bceb-11812a896dd5-23

This code system `http://hl7.org/fhir/comparison/CodeSystem/eb76ae3b-21b6-4ae4-bceb-11812a896dd5-23` defines codes, but no codes are represented here

Code | Display | Definition
SCA | Signer Certificate Authority (SCA) | A certificate which acts a trust anchor in the verification of the certificate chain for the DSCs issued by a Trust Network participant
DSC | Document Signing Certificate (DSC) | A certificate which may be used to verify a digital signature within a Verfifiable Digital Health Certificate
DECA | Data Exchange Certificate Authority (DECA) | A certificate which acts a trust anchor in the verification of the certificate chain for the DESCs issued by a Trust Network Participant
DESC | Data Exchange Signing Certificate (DESC) | A certificate which may be used to initiate a secure data exchange connection (e.g. mTLS) between Trust Network Participants
TLS | Transport Layer Security (TLS) | Used for establishing (m)TLS connections with systems, in particular between the Trust Network Gateway and backend systems of a Trust Network Participant
UP | Upload (UP) | Used to verify digital signature of cryptographically signed content uploaded to services within the Global Digital Health Certification Network, in particular the Trust Network Gateway