if err != nil {
					return tls.Certificate{}, fmt.Errorf("Unable to load KES client private key as specified by the shell environment: %v", err)
				}
				privateKeyPEM, rest := pem.Decode(bytes.TrimSpace(keyBytes))
				if len(rest) != 0 {
					return tls.Certificate{}, errors.New("Unable to load KES client private key as specified by the shell environment: private key contains additional data")
				}