天地无用--Java Cryptographic Extension (JCE) 框架的核心应用(转)

本文简单介绍了JCE框架的核心应用! javax.crypto.Cipher此类为加密和解密提供密码功能。它构成了 Java Cryptographic Extension (JCE) 框架的核心。为创建 Cipher 对象，应用程序调用 Cipher 的 getInstance 方法并将所请求转换的名称传递给它。还可以指定提供者的名称（可选）。转换是一个字符串，它描述为产生某种输出而在给定的输入上执行的操作（或一组操作）。转换始终包括加密算法的名称（例如，DES），后面可能跟有一个反馈模式和填充方案。 package thtf.com.cn.client; import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.io.OutputStream;import java.security.Key;import java.security.SecureRandom;import java.security.spec.AlgorithmParameterSpec;import java.util.ArrayList;import java.util.Collection;import java.util.Iterator;import java.util.Properties; import javax.crypto.Cipher;import javax.crypto.CipherInputStream;import javax.crypto.CipherOutputStream;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.spec.IvParameterSpec; import sun.misc.BASE64Decoder;import sun.misc.BASE64Encoder; //JCE应用public class MainEncrypt { static String keyFile = "c:/key.xml"; static Properties property = getProperties(); Cipher ecipher; Cipher dcipher; private final String JDBCPROPERTIES_PATH = "socket_jdbc.properties"; /** * 生成密钥。 * */ public static void saveDesKey() { try { keyFile = property.getProperty("keyFile"); SecureRandom sr = new SecureRandom(); // 为我们选择的DES算法生成一个KeyGenerator对象 KeyGenerator kg = KeyGenerator.getInstance("DES"); kg.init(sr); FileOutputStream fos = new FileOutputStream(keyFile); ObjectOutputStream oos = new ObjectOutputStream(fos); // 生成密钥 SecretKey key = kg.generateKey(); oos.writeObject(key); oos.close(); } catch (Exception e) { e.printStackTrace(); } } /** * 得到密钥。 * * @return */ public static SecretKey getKey() { SecretKey kp = null; try { keyFile = property.getProperty("keyFile"); // String fileName = "conf/DesKey.xml"; // InputStream is = // DesUtil.class.getClassLoader().getResourceAsStream(keyFile); InputStream is = new FileInputStream(keyFile); ObjectInputStream oos = new ObjectInputStream(is); kp = (SecretKey) oos.readObject(); oos.close(); } catch (Exception e) { e.printStackTrace(); } return kp; } /** * 根据字符串得到key * * @param strKey * 密钥明文 */ public void getKey(String strKey) { try { KeyGenerator _generator = KeyGenerator.getInstance("DES"); _generator.init(new SecureRandom(strKey.getBytes())); Key key = _generator.generateKey(); _generator = null; } catch (Exception e) { e.printStackTrace(); } } public static Properties getProperties() { Properties property = new Properties(); // InputStream in = ClassLoader // .getSystemResourceAsStream("socket_jdbc.properties"); InputStream in = MainEncrypt.class.getClassLoader() .getResourceAsStream("socket_jdbc.properties"); try { property.load(in); } catch (IOException e) { e.printStackTrace(); } return property; } public MainEncrypt() { // SecretKey key = KeyUtil.getKey(); SecretKey key = getKey(); byte[] iv = new byte[] { (byte) 0x8E, 0x12, 0x39, (byte) 0x9C, 0x07, 0x72, 0x6F, 0x5A }; AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv); try { ecipher = Cipher.getInstance("DES/CBC/PKCS5Padding"); dcipher = Cipher.getInstance("DES/CBC/PKCS5Padding"); // CBC requires an initialization vector ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec); dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec); } catch (java.security.InvalidAlgorithmParameterException e) { } catch (javax.crypto.NoSuchPaddingException e) { } catch (java.security.NoSuchAlgorithmException e) { } catch (java.security.InvalidKeyException e) { } } public byte[] getBytes(InputStream is) throws Exception { byte[] data = null; Collection chunks = new ArrayList(); byte[] buffer = new byte[1024 * 1000]; int read = -1; int size = 0; while ((read = is.read(buffer)) != -1) { if (read > 0) { byte[] chunk = new byte[read]; System.arraycopy(buffer, 0, chunk, 0, read); chunks.add(chunk); size += chunk.length; } } if (size > 0) { ByteArrayOutputStream bos = null; try { bos = new ByteArrayOutputStream(size); for (Iterator itr = chunks.iterator(); itr.hasNext();) { byte[] chunk = (byte[]) itr.next(); bos.write(chunk); } data = bos.toByteArray(); } finally { if (bos != null) { bos.close(); } } } return data; } /** * 加密String明文输入,String密文输出 * * @param strMing * @return */ public String getEncString(String strMing) { if (strMing == null) { strMing = ""; } byte[] byteMi = null; byte[] byteMing = null; String strMi = ""; BASE64Encoder base64en = new BASE64Encoder(); try { byteMing = strMing.getBytes("UTF8"); byteMi = this.getEncCode(byteMing); strMi = base64en.encode(byteMi); } catch (Exception e) { e.printStackTrace(); } finally { base64en = null; byteMing = null; byteMi = null; } return strMi; } /** * 解密以String密文输入,String明文输出 * * @param strMi * @return */ public String getDesString(String strMi) { // byte[] byteMi = null; // String strMing = ""; // ByteArrayOutputStream baos = new ByteArrayOutputStream(); // // try { // byteMi = strMi.getBytes("UTF8"); // // this.decrypt(new ByteArrayInputStream(byteMi), baos); // strMing = new String(baos.toByteArray()); // } catch (Exception e) { // e.printStackTrace(); // } finally { // } // return strMing; BASE64Decoder base64De = new BASE64Decoder(); byte[] byteMing = null; byte[] byteMi = null; String strMing = ""; try { byteMi = base64De.decodeBuffer(strMi); byteMing = this.getDesCode(byteMi); strMing = new String(byteMing, "UTF8"); } catch (Exception e) { e.printStackTrace(); } finally { base64De = null; byteMing = null; byteMi = null; } return strMing; } /** * 加密以byte[]明文输入,byte[]密文输出 * * @param byteS * @return */ public byte[] getEncCode(byte[] byteS) { byte[] byteFina = null; Cipher cipher; try { // cipher = Cipher.getInstance("DES"); // cipher.init(Cipher.ENCRYPT_MODE, key,); // byteFina = cipher.doFinal(byteS); byteFina = ecipher.doFinal(byteS); } catch (Exception e) { e.printStackTrace(); } finally { cipher = null; } return byteFina; } /** * 解密以byte[]密文输入,以byte[]明文输出 * * @param byteD * @return */ public byte[] getDesCode(byte[] byteD) { Cipher cipher; byte[] byteFina = null; try { // cipher = Cipher.getInstance("DES"); // cipher.init(Cipher.DECRYPT_MODE, key); // byteFina = cipher.doFinal(byteD); byteFina = dcipher.doFinal(byteD); } catch (Exception e) { e.printStackTrace(); } finally { cipher = null; } return byteFina; } // Buffer used to transport the bytes from one stream to another byte[] buf = new byte[1024]; public void encrypt(InputStream in, OutputStream out) { try { // Bytes written to out will be encrypted out = new CipherOutputStream(out, ecipher); // Read in the cleartext bytes and write to out to encrypt int numRead = 0; while ((numRead = in.read(buf)) >= 0) { out.write(buf, 0, numRead); } // 关闭流在外面进行。 // out.close(); } catch (java.io.IOException e) { } } public void decrypt(InputStream in, OutputStream out) { try { // Bytes read from in will be decrypted in = new CipherInputStream(in, dcipher); // Read in the decrypted bytes and write the cleartext to out int numRead = 0; while ((numRead = in.read(buf)) >= 0) { out.write(buf, 0, numRead); } // out.flush(); // 关闭流在外面进行。 // out.close(); } catch (java.io.IOException e) { } } /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub try { MainEncrypt encrypter = new MainEncrypt(); // Encrypt// encrypter.encrypt(new FileInputStream("c:/photo.jpg"),// new FileOutputStream("c:/photo_enc.jpg")); // Decrypt encrypter.decrypt(new FileInputStream("c:/photo_enc.jpg"), new FileOutputStream("c:/photo_des.jpg")); } catch (Exception e) { e.printStackTrace(); } } } 原文地址:http://blog.csdn.net/HuDon/archive/2008/04/04/2252385.aspx

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