Java tutorial
package org.bouncycastle.jce; import java.io.IOException; import java.security.cert.CRLException; import java.security.cert.CertificateEncodingException; import java.security.cert.X509CRL; import java.security.cert.X509Certificate; import org.bouncycastle.asn1.ASN1Primitive; import org.bouncycastle.asn1.x509.TBSCertList; import org.bouncycastle.asn1.x509.TBSCertificateStructure; import org.bouncycastle.asn1.x509.X509Name; /** * a utility class that will extract X509Principal objects from X.509 certificates. * <p> * Use this in preference to trying to recreate a principal from a String, not all * DNs are what they should be, so it's best to leave them encoded where they * can be. */ public class PrincipalUtil { /** * return the issuer of the given cert as an X509PrincipalObject. */ public static X509Principal getIssuerX509Principal(X509Certificate cert) throws CertificateEncodingException { try { TBSCertificateStructure tbsCert = TBSCertificateStructure .getInstance(ASN1Primitive.fromByteArray(cert.getTBSCertificate())); return new X509Principal(X509Name.getInstance(tbsCert.getIssuer())); } catch (IOException e) { throw new CertificateEncodingException(e.toString()); } } /** * return the subject of the given cert as an X509PrincipalObject. */ public static X509Principal getSubjectX509Principal(X509Certificate cert) throws CertificateEncodingException { try { TBSCertificateStructure tbsCert = TBSCertificateStructure .getInstance(ASN1Primitive.fromByteArray(cert.getTBSCertificate())); return new X509Principal(X509Name.getInstance(tbsCert.getSubject())); } catch (IOException e) { throw new CertificateEncodingException(e.toString()); } } /** * return the issuer of the given CRL as an X509PrincipalObject. */ public static X509Principal getIssuerX509Principal(X509CRL crl) throws CRLException { try { TBSCertList tbsCertList = TBSCertList.getInstance(ASN1Primitive.fromByteArray(crl.getTBSCertList())); return new X509Principal(X509Name.getInstance(tbsCertList.getIssuer())); } catch (IOException e) { throw new CRLException(e.toString()); } } }