private static AgentEncryptionKey loadKey(CredentialStoreService credentialStoreService) throws AmbariException {
    return new AgentEncryptionKey(credentialStoreService.getCredential(null, ALIAS).toValue());
  }
The encryption key which is used to encrypt sensitive data in agent config updates.
This key is shared with the agent so that it can decrypt the encrypted values.
ambari-server/src/main/java/org/apache/ambari/server/agent/AgentEncryptionKey.java