Java的DES算法实现

那一年像风

昨天按照网上的资料写DES,但最后在byte[]->String上卡住了.DES需要8位解密,而这种转换后,会讲btye[]补位造成长度和内容改变.很郁闷....最后又在网上找了一个已经实现的例子运行后无问题: 代码如下: package des; import java.security.Key; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; /** * * 使用DES加密与解密,可对byte[],String类型进行加密与解密 密文可使用String,byte[]存储. * * 方法: void getKey(String strKey)从strKey的字条生成一个Key * * String getEncString(String strMing)对strMing进行加密,返回String密文 String * getDesString(String strMi)对strMin进行解密,返回String明文 * * byte[] getEncCode(byte[] byteS)byte[]型的加密 byte[] getDesCode(byte[] * byteD)byte[]型的解密 */ public class DesEncrypt { Key key; /** * 根据参数生成KEY * * @param strKey */ public void getKey(String strKey) { try { KeyGenerator _generator = KeyGenerator.getInstance("DES"); _generator.init(new SecureRandom(strKey.getBytes())); this.key = _generator.generateKey(); _generator = null; } catch (Exception e) { e.printStackTrace(); } } /** * 加密String明文输入,String密文输出 * * @param strMing * @return */ public String getEncString(String strMing) { byte[] byteMi = null; byte[] byteMing = null; String strMi = ""; try { return byte2hex(getEncCode(strMing.getBytes())); // byteMing = strMing.getBytes("UTF8"); // byteMi = this.getEncCode(byteMing); // strMi = new String( byteMi,"UTF8"); } catch (Exception e) { e.printStackTrace(); } finally { byteMing = null; byteMi = null; } return strMi; } /** [1] [2] [3] * 解密 以String密文输入,String明文输出 * * @param strMi * @return */ public String getDesString(String strMi) { byte[] byteMing = null; byte[] byteMi = null; String strMing = ""; try { return new String(getDesCode(hex2byte(strMi.getBytes()))); // byteMing = this.getDesCode(byteMi); // strMing = new String(byteMing,"UTF8"); } catch (Exception e) { e.printStackTrace(); } finally { byteMing = null; byteMi = null; } return strMing; } /** * 加密以byte[]明文输入,byte[]密文输出 * * @param byteS * @return */ private byte[] getEncCode(byte[] byteS) { byte[] byteFina = null; Cipher cipher; try { cipher = Cipher.getInstance("DES"); cipher.init(Cipher.ENCRYPT_MODE, key); byteFina = cipher.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 */ 上一页 [1] [2] [3] private byte[] getDesCode(byte[] byteD) { Cipher cipher; byte[] byteFina = null; try { cipher = Cipher.getInstance("DES"); cipher.init(Cipher.DECRYPT_MODE, key); byteFina = cipher.doFinal(byteD); } catch (Exception e) { e.printStackTrace(); } finally { cipher = null; } return byteFina; } /** * 二行制转字符串 * * @param b * @return */ public static String byte2hex(byte[] b) { // 一个字节的数， // 转成16进制字符串 String hs = ""; String stmp = ""; for (int n = 0; n < b.length; n ) { // 整数转成十六进制表示 stmp = (java.lang.Integer.toHexString(b[n] & 0XFF)); if (stmp.length() == 1) hs = hs "0" stmp; else hs = hs stmp; } return hs.toUpperCase(); // 转成大写 } public static byte[] hex2byte(byte[] b) { if ((b.length % 2) != 0) throw new IllegalArgumentException("长度不是偶数"); byte[] b2 = new byte[b.length / 2]; for (int n = 0; n < b.length; n = 2) { String item = new String(b, n, 2); // 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个进制字节 b2[n / 2] = (byte) Integer.parseInt(item, 16); } return b2; } public static void main(String[] args) { System.out.println("hello"); DesEncrypt des = new DesEncrypt();//实例化一个对像 des.getKey("aadd");//生成密匙 String strEnc = des.getEncString("云海飞舞雲122");//加密字符串,返回String的密文 System.out.println(strEnc); String strDes = des.getDesString(strEnc);//把String 类型的密文解密 System.out.println(strDes); new DesEncrypt(); } } 上一页 [1] [2] [3]