对文件进行对称的DES加密
package com.ivan.security.algorithm;/** * 对字符流进行对称的DES加密 * @author Ivan * @DataTime 2006-12-11 12:34 * */import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.security.NoSuchAlgorithmException;import java.security.Security;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.NoSuchPaddingException;import javax.crypto.SecretKey;import sun.misc.BASE64Decoder;import sun.misc.BASE64Encoder;import com.iuxi.security.util.*;public class DESUtil ...{ private static String Algorithm = "DESede"; //"DESede" for Triple DES private static KeyGenerator keyGen = null; private static SecretKey desKey = null; private static Cipher c = null; private static byte[] cipherByte = null; public DESUtil() ...{ init(); } public static void init() ...{ try ...{ c = Cipher.getInstance(Algorithm); } catch (NoSuchAlgorithmException e) ...{ System.err.println("初始化错误，原因：所指定的算法无效！"); e.printStackTrace(); } catch (NoSuchPaddingException e) ...{ e.printStackTrace(); } } public static String getAlgorithm() ...{ return Algorithm; } public static void setAlgorithm(String algorithm) ...{ DESUtil.Algorithm = algorithm; } public static void setDesKey (SecretKey desKey) ...{ DESUtil.desKey = desKey; } /** *//** * 保存密钥信息到磁盘 * @param filepath 保存路径 * @return */ public static void saveKey(String filePath) ...{ if (desKey != null) ...{ try ...{ FileOutputStream fos = new FileOutputStream(filePath); ObjectOutputStream oos = new ObjectOutputStream(fos); oos.writeObject(desKey); }catch (IOException e) ...{ System.err.println("保存密钥信息出错！"); e.printStackTrace(); } } else ...{ System.err.println("保存密钥失败，密钥不存在！"); } } /** *//** * 从磁盘读取密钥信息 * @param filePath * @return */ public static SecretKey readKey(String filePath) ...{ try ...{ FileInputStream fis = new FileInputStream(filePath); fis = new FileInputStream(filePath); ObjectInputStream ois = new ObjectInputStream(fis); desKey = (SecretKey) ois.readObject(); ois.close(); fis.close(); }catch (FileNotFoundException e) ...{ System.err.println("读取密钥信息出错，原因：找不到指定的文件！"); } catch (IOException ex) ...{ System.err.println("读取密钥信息出错，原因：IO错误！"); ex.printStackTrace(); } catch (Exception ex) ...{ ex.printStackTrace(); } return desKey; } /** *//** * 按照指定的算法生成密钥 * @param algorithm 所指定的算法 * @return 生成的密钥 */ public static SecretKey genKey (String algorithm) ...{ try ...{ keyGen = KeyGenerator.getInstance(algorithm); } catch (NoSuchAlgorithmException e) ...{ System.err.println("生成密钥失败，原因：所指定的算法无效！"); e.printStackTrace(); } desKey = keyGen.generateKey(); return desKey; } /** *//** * 加密已转化为字节串的字符流 * @param rawByte 原始字节串 * @return 加密后的字节串 */ public static byte[] encryptData(byte[] rawByte) ...{ if(desKey != null) ...{ try ...{ c.init(Cipher.ENCRYPT_MODE, desKey); cipherByte = c.doFinal(rawByte); } catch (java.security.InvalidKeyException ex) ...{ System.err.println("加密失败，密钥无效!"); ex.printStackTrace(); } catch (javax.crypto.BadPaddingException ex) ...{ System.err.println("加密失败!"); ex.printStackTrace(); } catch (javax.crypto.IllegalBlockSizeException ex) ...{ System.err.println("加密失败!"); ex.printStackTrace(); } catch (Exception ex) ...{ System.err.println("加密失败!"); ex.printStackTrace(); } } else ...{ System.err.println("加密失败，原因：密钥不存在！"); } return cipherByte; } /** *//** * 解密字节串 * @param cipherByte 密文字节串 * @return 解密后的字节串 */ public static byte[] decryptor(byte[] cipherByte) ...{ if(desKey != null) ...{ try ...{ c.init(Cipher.DECRYPT_MODE, desKey); cipherByte = c.doFinal(cipherByte); } catch (java.security.InvalidKeyException ex) ...{ ex.printStackTrace(); } catch (javax.crypto.BadPaddingException ex) ...{ ex.printStackTrace(); } catch (javax.crypto.IllegalBlockSizeException ex) ...{ ex.printStackTrace(); } catch (Exception ex) ...{ ex.printStackTrace(); } return (cipherByte); } else ...{ System.err.println("解密失败，原因：密钥不存在！"); return null; } } public static void main(String[] args) throws Exception ...{ DESUtil.init(); DESUtil.genKey("DESede"); DESUtil.saveKey("desKey.dat"); byte[] cipherData = DESUtil.encryptData("This is just a test!".getBytes()); String cipherString = new String(new BASE64Encoder().encode(cipherData)); System.out.println("密文数据为：" + cipherString); byte[] cipherByte = new BASE64Decoder().decodeBuffer(cipherString); String rawString = new String(DESUtil.decryptor(cipherByte)); System.out.println("解密后的原文为：" + rawString); }}
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