从字符串数据获取X509证书的到期日期

Question

I am trying to get expiry date of x509 certificate from xml file under tag

<ds:X509Certificate> MBaAFI7JTi5oRslwv2B3MmERGbPKKUsSMFwGA1UdIARVMFMwUQYKKwYBBAEJFQEBADBDMEEGCCsG
AQUFBwIBFjVodHRwOi8vd3d3LmNpc2NvLmNvbS9zZWN1cml0eS9wa2kvcG9saWNpZXMvaW5kZXgu
aHRtbDATBgNVHSUEDDAKBggrBgEFBQcDATANBgkqhkiG9w0BAQUFAAOCAQEAs2DJZwgVLmZqQS2N
3Yp4iGYhZBG6vZSDaiaAg6u1wgrfq/byBd7H3Ei+V9I7MZ1aCh4s3kl6FJ1CoRhMQcM1gbxpCbPP
KAfrMv/5/MH8erMnole7m/MqVHETX1UbLEyagOioqK3cs8MzMKxC+Fdku6Bm+i/6xhUsc6XbrVJl
IHsVBB9+9ZnpjAjC9jj21r04N51cyfp6C37999TaybNEtCJlG0XTHfLbcyX65E9ndVaRd6GYu/d0
xW0MT5bKhA36KhpUROAbPS7rXKKkfCYnMkmImE7Hfvm3vRSahX+ehY1Tx9qJXFv3PYGzbyDbvpjV
2cSUgP/bhGATKSOZuhohrw==  </ds:X509Certificate

>

I have code that reads it to a string

NodeList nodelist = element.getElementsByTagName("ds:X509Certificate");
Element element1 = (Element) nodelist.item(0);
NodeList certificateItem = element1.getChildNodes();
String certificateValue = "---- BEGIN CERTIFICATE -------- " + "\n" +
"certificateItem.item(0).getNodeValue()" + "\n" + "--- END CERTIFICATE";                            
System.out.print("Certificate data is : " + certificateValue);
InputStream certinputstream = new ByteArrayInputStream(certificateValue.getBytes());
CertificateFactory cf = CertificateFactory.getInstance("X.509");
X509Certificate cert = (X509Certificate)cf.generateCertificate(certinputstream);
System.out.println("Expiry Date : " + cert.getNotAfter());

But I am getting the following error java.security.cert.CertificateParsingException: invalid DER-encoded certificate data at sun.security.x509.X509CertImpl.parse(Unknown Source) at sun.security.x509.X509CertImpl.(Unknown Source) Any ideas ? Thanks

Answer 1

It's not clear whether this is all that's wrong, but you're not using the precise format specified in the CertificateFactory docs:

If the certificate is provided in Base64 encoding, it must be bounded at the beginning by -----BEGIN CERTIFICATE-----, and must be bounded at the end by -----END CERTIFICATE-----.

You've got spaces around the text, the wrong number of dashes, and you don't have dashes after END CERTIFICATE .

You may also want to trim the node value as it currently has a couple of spaces after the data.