Merge "Update Keymint documentation in aidl."

     * `attestationKey` parameter of `generateKey()`, `importKey()` or `importWrappedKey()`), and in

     * the non-attestaion case, whether the key can self-sign.

     *

     * 1.  Attestation with factory key.  If Tag::ATTESTATION_CHALLENGE is provided and the

     *     `attestationKey` parameter on the generate/import call is null, the returned certificate

     *     chain must contain an attestation certificate signed with a factory-provisioned

     *     attestation key, and the full certificate chain for that factory-provisioned attestation

     *     key.

     * 1.  Asymmetric key attestation with factory key.  If Tag::ATTESTATION_CHALLENGE is provided

     *     and the `attestationKey` parameter on the generate/import call is null, the returned

     *     certificate chain must contain an attestation certificate signed with a factory-

     *     provisioned attestation key, and the full certificate chain for that factory-provisioned

     *     attestation key.  Tag::ATTESTATION_APPLICATION_ID must also be provided when the

     *     ATTESTATION_CHALLENGE is provided, otherwise ATTESTATION_APPLICATION_ID_MISSING will be

     *     returned.

     *

     * 2.  Attestation with caller-provided key.  If Tag::ATTESTATION_CHALLENGE is provided and the

     *     `attestationKey` parameter on the generat/import call is non-null and contains the key

     *     blob of a key with KeyPurpose::ATTEST_KEY, the returned certificate chain must contain

     *     only an attestation certificate signed with the specified key.  The caller must know the

     *     certificate chain for the provided key.

     * 2.  Asymmetric key attestation with caller-provided key.  If Tag::ATTESTATION_CHALLENGE is

     *     provided and the `attestationKey` parameter on the generat/import call is non-null and

     *     contains the key blob of a key with KeyPurpose::ATTEST_KEY, the returned certificate

     *     chain must contain only an attestation certificate signed with the specified key.  The

     *     caller must know the certificate chain for the provided key.  Tag::

     *     ATTESTATION_APPLICATION_ID must also be provided when the ATTESTATION_CHALLENGE is

     *     provided, otherwise ATTESTATION_APPLICATION_ID_MISSING will be returned.

     *

     * 3.  Non-attestation with signing key.  If Tag::ATTESTATION_CHALLENGE is not provided and the

     *     generated/imported key has KeyPurpose::SIGN, then the returned certificate chain must

     *     contain only a single self-signed certificate with no attestation extension.

     * 3.  Asymmetric key non-attestation with signing key.  If Tag::ATTESTATION_CHALLENGE is not

     *     provided and the generated/imported key has KeyPurpose::SIGN, then the returned

     *     certificate chain must contain only a single self-signed certificate with no attestation

     *     extension.  Tag::ATTESTATION_APPLICATION_ID will be ignored if provided.

     *

     * 4.  Non-attestation with non-signing key.  If TAG::ATTESTATION_CHALLENGE is not provided and

     *     the generated/imported key does not have KeyPurpose::SIGN, then the returned certificate

     *     chain must contain only a single certificate with an empty signature and no attestation

     *     extension.

     * 4.  Asymmetric key non-attestation with non-signing key.  If TAG::ATTESTATION_CHALLENGE is

     *     not provided and the generated/imported key does not have KeyPurpose::SIGN, then the

     *     returned certificate chain must contain only a single certificate with an empty signature

     *     and no attestation extension.  Tag::ATTESTATION_APPLICATION_ID will be ignored if

     *     provided.

     *

     * 5.  Symmetric key.  If the generated/imported key is symmetric, the certificate chain must be

     *     empty.

     * 5.  Symmetric key.  If the generated/imported key is symmetric, the certificate chain must

     *     return empty, any Tag::ATTESTATION_CHALLENGE or Tag::ATTESTATION_APPLICATION_ID inputs,

     *     if provided, are ignored.

     */

    Certificate[] certificateChain;

}