The Amazon Resource Name (ARN) that was returned when you called CreateCertificateAuthority. This must be of the form:
arn:aws:acm-pca:region:account:certificate-authority/12345678-1234-1234-1234-123456789012
Optional CertificateA PEM-encoded file that contains all of your certificates, other than the certificate you're importing, chaining up to your root CA. Your Amazon Web Services Private CA-hosted or on-premises root certificate is the last in the chain, and each certificate in the chain signs the one preceding.
This parameter must be supplied when you import a subordinate CA. When you import a root CA, there is no chain.
The PEM-encoded certificate for a private CA. This may be a self-signed certificate in the case of a root CA, or it may be signed by another CA that you control.