java数字签名

java数字签名 数字签名的程序，供爱好者参考，赚点积分~~呵呵~ //DES Encrypt //加密 package com.chinacountry; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import java.security.Key; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.security.Security; /** * Created by IntelliJ IDEA. * User: Alan * Date: Dec 4, 2003 * Time: 9:29:19 PM * To change this template use Options | File Templates. */ public class EncryptUtil { /** * 获得DES加密的密钥。在交易处理的过程中应该定时更 * 换密钥。需要JCE的支持，如果jdk版本低于1.4，则需要 * 安装jce-1_2_2才能正常使用。 * @return Key 返回对称密钥 * @throws java.security.NoSuchAlgorithmException * @see cn.com.tdt.util.EncryptUtil 其中包括加密和解密的方法 */ public static Key getKey() throws NoSuchAlgorithmException { Security.insertProviderAt(new com.sun.crypto.provider.SunJCE(), 1); KeyGenerator generator = KeyGenerator.getInstance("DES"); generator.init(new SecureRandom()); Key key = generator.generateKey(); return key; } /** * 将指定的数据根据提供的密钥进行加密 * @param key 密钥 * @param data 需要加密的数据 * @return byte[] 加密后的数据 * @throws EncryptException */ public static byte[] doEncrypt(Key key, byte[] data) throws EncryptException { try { //Get a cipher object Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding"); //Encrypt cipher.init(Cipher.ENCRYPT_MODE, key); //byte[] stringBytes = amalgam.getBytes("UTF8"); byte[] raw = cipher.doFinal(data); //BASE64Encoder encoder = new BASE64Encoder(); //String base64 = encoder.encode(raw); return raw; } catch (Exception e) { e.printStackTrace(); throw new EncryptException("Do encrypt occurs Exception.[" + e.getMessage() + "]"); } } /** * 将给定的已加密的数据通过指定的密钥进行解密 * @param key 密钥 * @param raw 待解密的数据 * @return byte[] 解密后的数据 * @throws EncryptException */ public static byte[] doDecrypt(Key key, byte[] raw) throws EncryptException { try { //Get a cipher object Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding"); // Decrypt cipher.init(Cipher.DECRYPT_MODE, key); //BASE64Decoder decoder = new BASE64Decoder(); //byte[] raw = decoder.decodeBuffer(data); byte[] data = cipher.doFinal(raw); //String result = new String(stringBytes, "UTF8"); //System.out.println("the decrypted data is: " + result); return data; } catch (Exception e) { e.printStackTrace(); throw new EncryptException("Do decrypt occurs Exception.[" + e.getMessage() + "]"); } } public static Cipher getCipher(Key key, int cipherMode) throws EncryptException { try { Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding"); cipher.init(cipherMode, key); return cipher; } catch (Exception e) { e.printStackTrace(); throw new EncryptException("Do decrypt occurs Exception.[" + e.getMessage() + "]"); } } } I am sorry for my windows can't inputing Chinese. When I use des encrypt my data,it occurs that I use "Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");" at first and my application runs very well,but when data is coming from net in socket,it throws exception.The exception means that I use a wrong padding or padding size not right.It is confused with me.No information on internet,and a lots of guys also met this problem but no answer is given.I found that des is a type of encrypt block,so I try to use "Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");" replace original code and put some '\0' to byte[] to make byte[] divided with 8.This problem is resoveled,who have met problem like that.We can talk about it. my email: xiaoyusong@etang.com ----------------------------------------------------------------------------------------------------------------------------------------------- 数字签证 加密最好还是用java来做，而不要用数据库自带的加密函数，因为那样容易失去对数据库的 平滑支持。加密你可以考虑用mac或者des加密，前者是非对称密钥(分为公钥和私钥，只 有持有私钥的人才可以加密数据，而公钥仅仅是匹配私钥用来解密)更加安全可靠，或者是 对称密钥(持有密钥人的密钥都是一样的可以双向加密和解密)。数字签名仅仅用来证明内容 没有被修改，不是用来加密的。数字签名仅仅用来证明内容没有被修改，不是用来加密的。 你可以将加密后的数据+数字签名就保险多了。 代码网上很多我这里只有des加密和数字签名的代码，你需要稍微修改一下。 des加密:;;Forum_ID=29 数字签名: /** * @version 1.10 1999-10-05 * @author Cay Horstmann */ import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class TestMessageDigest { public static void main(String[] args) { JFrame f = new MessageDigestFrame(); f.show(); } } class MessageDigestFrame extends JFrame { public MessageDigestFrame() { setTitle("MessageDigestTest"); setSize(400, 200); addWindowListener( new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); JPanel panel = new JPanel(); ButtonGroup group = new ButtonGroup(); ActionListener listener = new ActionListener() { public void actionPerformed(ActionEvent event) { JCheckBox b = (JCheckBox) event.getSource(); setAlgorithm(b.getText()); } }; addCheckBox(panel, "SHA-1", group, true, listener); addCheckBox(panel, "MD5", group, false, listener); Container contentPane = getContentPane(); contentPane.add(panel, "North"); contentPane.add(new JScrollPane(message), "Center"); contentPane.add(digest, "South"); digest.setFont(new Font("Monospaced", Font.PLAIN, 12)); setAlgorithm("SHA-1"); JMenuBar menuBar = new JMenuBar(); JMenu menu = new JMenu("File"); JMenuItem fileDigestItem = new JMenuItem("File digest"); fileDigestItem.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent event) { loadFile(); } }); menu.add(fileDigestItem); JMenuItem textDigestItem = new JMenuItem("Text area digest"); textDigestItem.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent event) { String m = message.getText(); computeDigest(m.getBytes()); } }); menu.add(textDigestItem); menuBar.add(menu); setJMenuBar(menuBar); } public void addCheckBox(Container c, String name, ButtonGroup g, boolean selected, ActionListener listener) { JCheckBox b = new JCheckBox(name, selected); c.add(b); g.add(b); b.addActionListener(listener); } public void setAlgorithm(String alg) { try { currentAlgorithm = MessageDigest.getInstance(alg); digest.setText(""); } catch (NoSuchAlgorithmException e) { digest.setText("" + e); } } public void loadFile() { JFileChooser chooser = new JFileChooser(); chooser.setCurrentDirectory(new File(".")); int r = chooser.showOpenDialog(this); if (r == JFileChooser.APPROVE_OPTION) { String name = chooser.getSelectedFile().getAbsolutePath(); computeDigest(loadBytes(name)); } } public byte[] loadBytes(String name) { FileInputStream in = null; try { in = new FileInputStream(name); ByteArrayOutputStream buffer = new ByteArrayOutputStream(); int ch; while ((ch = in.read()) != -1) buffer.write(ch); return buffer.toByteArray(); } catch (IOException e) { if (in != null) { try { in.close(); } catch (IOException e2) { } } return null; } } public void computeDigest(byte[] b) { currentAlgorithm.reset(); currentAlgorithm.update(b); byte[] hash = currentAlgorithm.digest(); String d = ""; for (int i = 0; i < hash.length; i++) { int v = hash & 0xFF; if (v < 16) d += "0"; d += Integer.toString(v, 16).toUpperCase() + " "; } digest.setText(d); } private JTextArea message = new JTextArea(); private JTextField digest = new JTextField(); private MessageDigest currentAlgorithm; } /*你可以将文件放到byte数组中，然后加密获得另一个数组(实际上就是加密后的文件)。为加密数据取得签名，再将签名和密钥发送给需要的人，就可以了～ */