1 files changed, 62 insertions, 0 deletions
diff --git a/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/sl20/X509Utils.java b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/sl20/X509Utils.java
new file mode 100644
index 00000000..391b8271
--- /dev/null
+++ b/pdf-as-web/src/main/java/at/gv/egiz/pdfas/web/sl20/X509Utils.java
@@ -0,0 +1,62 @@
+package at.gv.egiz.pdfas.web.sl20;
+
+import java.security.cert.X509Certificate;
+import java.util.List;
+
+import javax.security.auth.x500.X500Principal;
+
+public class X509Utils {
+
+	  /**
+	   * Sorts the Certificate Chain by IssuerDN and SubjectDN. The [0]-Element should be the Hostname,
+	   * the last Element should be the Root Certificate.
+	   * 
+	   * @param certs
+	   *          The first element must be the correct one.
+	   * @return sorted Certificate Chain
+	   */
+	  public static List<X509Certificate> sortCertificates(
+		      List<X509Certificate> certs)
+		  {
+		    int length = certs.size();
+		    if (certs.size() <= 1)
+		    {
+		      return certs;
+		    }
+
+		    for (X509Certificate cert : certs)
+		    {
+		      if (cert == null)
+		      {
+		        throw new NullPointerException();
+		      }
+		    }
+
+		    for (int i = 0; i < length; i++)
+		    {
+		      boolean found = false;
+		      X500Principal issuer = certs.get(i).getIssuerX500Principal();
+		      for (int j = i + 1; j < length; j++)
+		      {
+		        X500Principal subject = certs.get(j).getSubjectX500Principal();
+		        if (issuer.equals(subject))
+		        {
+		          // sorting necessary?
+		          if (i + 1 != j)
+		          {
+		            X509Certificate tmp = certs.get(i + 1);
+		            certs.set(i + 1, certs.get(j));
+		            certs.set(j, tmp);
+		          }
+		          found = true;
+		        }
+		      }
+		      if (!found)
+		      {
+		        break;
+		      }
+		    }
+
+		    return certs;
+		}
+}