From 33613a85afc4b1481367fbe92a17ee59c240250b Mon Sep 17 00:00:00 2001
From: Sven Eisenhauer <sven@sven-eisenhauer.net>
Date: Fri, 10 Nov 2023 15:11:48 +0100
Subject: add new repo

---
 .../hjp5/examples/DigitalSignature.java            | 47 ++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 Master/Reference Architectures and Patterns/hjp5/examples/DigitalSignature.java

(limited to 'Master/Reference Architectures and Patterns/hjp5/examples/DigitalSignature.java')

diff --git a/Master/Reference Architectures and Patterns/hjp5/examples/DigitalSignature.java b/Master/Reference Architectures and Patterns/hjp5/examples/DigitalSignature.java
new file mode 100644
index 0000000..7a7b809
--- /dev/null
+++ b/Master/Reference Architectures and Patterns/hjp5/examples/DigitalSignature.java	
@@ -0,0 +1,47 @@
+/* DigitalSignature.java */
+
+import java.io.*;
+import java.security.cert.Certificate;
+import java.security.*;
+
+public class DigitalSignature
+{
+  static final String KEYSTORE = "c:\\windows\\.keystore";
+  static final char[] KSPASS   = {'h','j','p','3','k','s'};
+  static final String ALIAS    = "hjp3";
+  static final char[] KEYPASS  = {'h','j','p','3','k','e','y'};
+
+  public static void main(String[] args)
+  {
+    try {
+      //Laden der Schlüsseldatenbank
+      KeyStore ks = KeyStore.getInstance("JKS");
+      FileInputStream ksin = new FileInputStream(KEYSTORE);
+      ks.load(ksin, KSPASS);
+      ksin.close();
+      //Privaten Schlüssel "hjp3" lesen
+      Key key = ks.getKey(ALIAS, KEYPASS);
+      //Signatur-Objekt erstellen
+      Signature signature = Signature.getInstance("SHA/DSA");
+      signature.initSign((PrivateKey)key);
+      //Eingabedatei einlesen
+      FileInputStream in = new FileInputStream(args[0]);
+      int len;
+      byte[] data = new byte[1024];
+      while ((len = in.read(data)) > 0) {
+        //Signatur updaten
+        signature.update(data, 0, len);
+      }
+      in.close();
+      //Signatur berechnen
+      byte[] result = signature.sign();
+      //Signatur ausgeben
+      FileOutputStream out = new FileOutputStream(args[1]);
+      out.write(result, 0, result.length);
+      out.close();
+    } catch (Exception e) {
+      System.err.println(e.toString());
+      System.exit(1);
+    }
+  }
+}
\ No newline at end of file
-- 
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