The user you specify in the Run As Username field during replication policy creation requires full access to both the key and the data directories being replicated. This is not a recommended best practice for KMS management. If you change permissions in the KMS to enable this requirement, you could accidentally provide access for this user to data in other encryption zones using the same key. If a user is not specified in the Run As Username field, the replication runs as the default user, hdfs.
To access encrypted data, the user must be authorized on the KMS for the encryption zones they need to interact with. The user you specify in thefield during replication policy creation must have this authorization. The key administrator must add ACLs to the KMS for that user to prevent authorization failure.
Key transfer using the KMS protocol from source to the client uses the REST protocol, which requires that you configure TLS/SSL for the KMS. When TLS/SSL is enabled, keys are not transferred over the network as plain text.