ACMPCA / Client / import_certificate_authority_certificate



Imports a signed private CA certificate into Amazon Web Services Private CA. This action is used when you are using a chain of trust whose root is located outside Amazon Web Services Private CA. Before you can call this action, the following preparations must in place:

  • In Amazon Web Services Private CA, call the CreateCertificateAuthority action to create the private CA that you plan to back with the imported certificate.

  • Call the GetCertificateAuthorityCsr action to generate a certificate signing request (CSR).

  • Sign the CSR using a root or intermediate CA hosted by either an on-premises PKI hierarchy or by a commercial CA.

  • Create a certificate chain and copy the signed certificate and the certificate chain to your working directory.

Amazon Web Services Private CA supports three scenarios for installing a CA certificate:

  • Installing a certificate for a root CA hosted by Amazon Web Services Private CA.

  • Installing a subordinate CA certificate whose parent authority is hosted by Amazon Web Services Private CA.

  • Installing a subordinate CA certificate whose parent authority is externally hosted.

The following additional requirements apply when you import a CA certificate.

  • Only a self-signed certificate can be imported as a root CA.

  • A self-signed certificate cannot be imported as a subordinate CA.

  • Your certificate chain must not include the private CA certificate that you are importing.

  • Your root CA must be the last certificate in your chain. The subordinate certificate, if any, that your root CA signed must be next to last. The subordinate certificate signed by the preceding subordinate CA must come next, and so on until your chain is built.

  • The chain must be PEM-encoded.

  • The maximum allowed size of a certificate is 32 KB.

  • The maximum allowed size of a certificate chain is 2 MB.

Enforcement of Critical Constraints

Amazon Web Services Private CA allows the following extensions to be marked critical in the imported CA certificate or chain.

  • Basic constraints (must be marked critical)

  • Subject alternative names

  • Key usage

  • Extended key usage

  • Authority key identifier

  • Subject key identifier

  • Issuer alternative name

  • Subject directory attributes

  • Subject information access

  • Certificate policies

  • Policy mappings

  • Inhibit anyPolicy

Amazon Web Services Private CA rejects the following extensions when they are marked critical in an imported CA certificate or chain.

  • Name constraints

  • Policy constraints

  • CRL distribution points

  • Authority information access

  • Freshest CRL

  • Any other extension

See also: AWS API Documentation

Request Syntax

response = client.import_certificate_authority_certificate(
  • CertificateAuthorityArn (string) –


    The Amazon Resource Name (ARN) that was returned when you called CreateCertificateAuthority. This must be of the form:


  • Certificate (bytes) –


    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.

  • CertificateChain (bytes) –

    A 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.