解析ASN.1为OCSPRequest

上次把ASN.1解析得到了具体对象，但是难以理解对应的意义。这次是解析为Bouncy Castle下的OCSPRequest结构。

先了解一下OCSPRequest的结构:

public class OCSPRequest
    extends ASN1Object
{
    TBSRequest      tbsRequest;
    Signature       optionalSignature;
}

public class TBSRequest
    extends ASN1Object
{
    private static final ASN1Integer V1 = new ASN1Integer(0);
    
    ASN1Integer      version;
    GeneralName     requestorName;
    ASN1Sequence    requestList;
    Extensions  requestExtensions;
}

public class Signature
    extends ASN1Object
{
    AlgorithmIdentifier signatureAlgorithm;
    DERBitString        signature;
    ASN1Sequence        certs;
}

public class AlgorithmIdentifier
    extends ASN1Object
{
    private ASN1ObjectIdentifier algorithm;
    private ASN1Encodable       parameters;
}

 更多结构可点进去查看，这里只写本文用到的。

 给定这样一个Bouncy Castle的signedReq：

String signedReq =
        "MIIC9jBAMD4wPDA6MAkGBSsOAwIaBQAEFENv0Y4OeruVGFKQSrDhdfbiG4RHBBTc"
      + "Mr1fP+mZAxbF2ZdehWxn6mtAngIBAaCCArAwggKsMA0GCSqGSIb3DQEBBQUAA4GB"
      + "AAzHBm4nL5AcRQB3Jkz7ScNeZF+GbRZ0p4kBDTnqi3IeESuso12yJhpqqyijdnj5"
      + "gd4/GsSAgdluLHyYZ6wgozV7G9MDXCnFnG4PBUW05HaVX81JYAp+amVyU0NOgNrG"
      + "90npVBsHb0o+UlkxNgMiEbSkp/TeGb6YURsYKhmwp7BgoIICFTCCAhEwggINMIIB"
      + "dqADAgECAgEBMA0GCSqGSIb3DQEBBAUAMCUxFjAUBgNVBAoTDUJvdW5jeSBDYXN0"
      + "bGUxCzAJBgNVBAYTAkFVMB4XDTA0MTAyNDEzNDc0M1oXDTA1MDIwMTEzNDc0M1ow"
      + "JTEWMBQGA1UEChMNQm91bmN5IENhc3RsZTELMAkGA1UEBhMCQVUwgZ8wDQYJKoZI"
      + "hvcNAQEBBQADgY0AMIGJAoGBAJBmLeIzthMHUeTkOeJ76iBxcMHY31o/i3a9VT12"
      + "y2FcS/ejJmeUCMTdtwl5alOwXY66vF4DyT1VU/nJG3mHpSoqq7qrMXOIFGcXg1Wf"
      + "oJRrQgTOLdQ6bod7i9ME/EjEJy70orh0nVS7NGcu0R5TjcbLde2J5zxjb/W9wqfy"
      + "RovJAgMBAAGjTTBLMB0GA1UdDgQWBBTcMr1fP+mZAxbF2ZdehWxn6mtAnjAfBgNV"
      + "HSMEGDAWgBTcMr1fP+mZAxbF2ZdehWxn6mtAnjAJBgNVHRMEAjAAMA0GCSqGSIb3"
      + "DQEBBAUAA4GBAF/4EH1KkNrNxocJPIp7lThmG1KIVYESIadowMowrbok46ESofRF"
      + "OIPku07W+e1Y1Y1KXLIiPMG3IGwrBrn04iLsbbBUiN37BcC/VyT4xKJ2MYscGjKL"
      + "ua/9bU0lOyeTRAwqb8towWRd5lLYAI3RQ7dhStUTFp3Vqd803PJ/cpR6";

下面是解析代码：

        byte[] d64 = Base64.decode(signedReq)；
        ASN1InputStream asn1InputStream = new ASN1InputStream(d64);
        try {
            //强制转换类型
            OCSPRequest req = OCSPRequest.getInstance(asn1InputStream.readObject());
            //依然是先打断点判断有什么结构，再写结构。

            //tbsRequest部分
            TBSRequest tbsRequest = req.getTbsRequest();

            ASN1Integer asn1Integer = tbsRequest.getVersion();
            GeneralName generalName = tbsRequest.getRequestorName();
            ASN1Sequence requestList = tbsRequest.getRequestList();

            Extensions extensions = tbsRequest.getRequestExtensions();

            System.out.println("tbsRequest值：");
            System.out.println("version:--------------" + asn1Integer);
            System.out.println("generalName:--------------" + generalName);
            System.out.println("requestList:--------------" +  requestList);
            System.out.println("extensions:--------------" + extensions);
            //signature部分
            Signature signature = req.getOptionalSignature();

            System.out.println("signature值：");
            if (signature == null) {
                System.out.println("signature为空");//空
            } else {
                AlgorithmIdentifier algorithmIdentifier = signature.getSignatureAlgorithm();

                ASN1ObjectIdentifier algorithm = algorithmIdentifier.getAlgorithm();
                ASN1Encodable       parameters = algorithmIdentifier.getParameters();
                System.out.println("algorithm:--------------"+algorithm);
                System.out.println("parameters:--------------"+parameters);

                DERBitString derBitString = signature.getSignature();
                System.out.println("signature:--------------"+derBitString);

                ASN1Sequence certs = signature.getCerts();
                System.out.println("certs:--------------"+certs);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    

main方法调用一下：

解析完成！