DES对称分组密码系统的Java实现

DES对称分组密码系统 import java.security.spec.*; import javax.crypto.*; import javax.crypto.spec.*; class DES01 { private String strkey; private SecretKey skey=null; private String[] algo= {"DES/ECB/PKCS5Padding","DES/ECB/NoPadding","DES"}; public DES01(String key) { strkey=key; } public void keyGenerating() throws Exception { byte[] bkey=strkey.getBytes(); KeySpec ks = new DESKeySpec(bkey); SecretKeyFactory kf = SecretKeyFactory.getInstance("DES"); skey = kf.generateSecret(ks); } public static void main(String[] a) { DES01 des = new DES01("IAMASTUDENT"); des.test02("STUDENTWANGFENGLIMING"); } public byte[] Encripting(String plaintext,int i) throws Exception { byte[] bpt=plaintext.getBytes(); Cipher cf = Cipher.getInstance(algo[i]); if(skey==null)this.keyGenerating(); cf.init(Cipher.ENCRYPT_MODE,skey); byte[] bct = cf.doFinal(bpt); return bct; } public byte[] decripting(byte[] bct,int i) throws Exception { Cipher cf = Cipher.getInstance(algo[i]); if(skey==null)this.keyGenerating(); cf.init(Cipher.DECRYPT_MODE,skey); byte[] bpt = cf.doFinal(bct); return bpt; } public void test01(String mess) { try{ byte[] ct=this.Encripting(mess,0); byte[] pt=this.Decripting(ct,0); String ptt=new String(pt); System.out.println(ptt); }catch(Exception ex) { return; } } public void test02(String mess) { try{ //Encripting print("Plaintext to be encripted:"); print(mess); byte[] ct=this.Encripting(mess,0); //Exploiting the results print("Byte array of cipher:"); for(int i=0;i