Information Encryption and information encryption technology

Information Encryption and information encryption technology

There are various encryption methods for information. We have introduced a self-designed encryption method. If you are interested, you can enjoy it. Thank you for your advice. Today, we will introduce the symmetric encryption method. The so-called symmetric encryption refers to the symmetric format of encryption and decryption methods, that is, decryption is the inverse process of encryption. Let's take a look at it: the encryption strength of DES, 3DES, AES, and PBE increases sequentially. Well, let's talk less about the Code:

First, let's take a look at DES:

Package cn.edu. hpu. des; import java. security. key; import javax. crypto. cipher; import javax. crypto. keyGenerator; import javax. crypto. secretKey; import javax. crypto. secretKeyFactory; import javax. crypto. spec. DESKeySpec; public class jdk_DES {private static final String src = "I Love You! "; Public static void main (String [] args) {jdk_DES.jdkDES () ;}@ SuppressWarnings (" static-access ") public static void jdkDES () {try {// obtain KEY KeyGenerator keyGenerator = KeyGenerator. getInstance ("DES"); keyGenerator. init (56); // set it to the default value 56. // you can obtain the KEY object SecretKey secrekeyone = keyGenerator. generateKey (); byte [] byteskey = secrekeyone. getEncoded (); // KEY conversion DESKeySpec deskeyspec = new DESKeySpec (byteskey); SecretKeyFactory factory = SecretKeyFactory. getInstance ("DES"); Key secerkeytwo = factory. generateSecret (deskeyspec); // encrypt Cipher cipher = Cipher. getInstance ("DES/ECB/PKCS5Padding"); cipher. init (cipher. ENCRYPT_MODE, secerkeytwo); // sets the mode to encrypted byte [] result = cipher. doFinal (src. getBytes (); System. out. println ("jdkEDS:" + result. toString (); // decrypt cipher. init (cipher. DECRYPT_MODE, secerkeytwo); // sets the decryption mode to result = cipher. doFinal (result); System. out. println ("jdkEDS:" + new String (result);} catch (Exception e) {e. printStackTrace ();}}}

Running result:

The second three-weight DES:

Package cn.edu. hpu. des; import java. security. key; import java. security. secureRandom; import javax. crypto. cipher; import javax. crypto. keyGenerator; import javax. crypto. secretKey; import javax. crypto. secretKeyFactory; import javax. crypto. spec. DESKeySpec; public class jdk_3DES {private static final String src = "I Love You! "; Public static void main (String [] args) {jdk_3DES.jdk3DES () ;}@ SuppressWarnings (" static-access ") public static void jdk3DES () {try {// obtain KEY KeyGenerator keyGenerator = KeyGenerator. getInstance ("DESede"); // keyGenerator. init (112); // set the key length. The default value is 168, or 112 keyGenerator. init (new SecureRandom (); // set it to the default value // obtain the KEY object SecretKey secrekeyone = keyGenerator. generateKey (); byte [] byteskey = secrekeyone. getEncoded (); // KEY conversion DESKeySpec deskeyspec = new DESKeySpec (byteskey); SecretKeyFactory factory = SecretKeyFactory. getInstance ("DES"); Key secerkeytwo = factory. generateSecret (deskeyspec); // encrypt Cipher cipher = Cipher. getInstance ("DES/ECB/PKCS5Padding"); cipher. init (cipher. ENCRYPT_MODE, secerkeytwo); // sets the mode to encrypted byte [] result = cipher. doFinal (src. getBytes (); System. out. println ("jdkEDS:" + result. toString (); // decrypt cipher. init (cipher. DECRYPT_MODE, secerkeytwo); // sets the decryption mode to result = cipher. doFinal (result); System. out. println ("jdkEDS:" + new String (result);} catch (Exception e) {e. printStackTrace ();}}}

Running result:

Third AES:

Package cn.edu. hpu. aes; import java. security. key; import java. security. secureRandom; import javax. crypto. cipher; import javax. crypto. keyGenerator; import javax. crypto. secretKey; import javax. crypto. spec. secretKeySpec; public class jdk_AES {private static final String src = "I Love You! "; Public static void main (String [] args) {AES ();} public static void AES () {try {// obtain key KeyGenerator keyGenerator = KeyGenerator. getInstance ("AES"); keyGenerator. init (new SecureRandom (); // The default key length is: SecretKey secretKey = keyGenerator. generateKey (); byte [] keyBytes = secretKey. getEncoded (); // key to convert Key key = new SecretKeySpec (keyBytes, "AES"); // encrypt Cipher cipher = Cipher. getInstance ("AES/ECB/PKCS5Padding"); cipher. init (Cipher. ENCRYPT_MODE, key); byte [] result = cipher. doFinal (src. getBytes (); System. out. println ("AES =" + result. toString (); // decrypt cipher. init (Cipher. DECRYPT_MODE, key); result = cipher. doFinal (result); System. out. println ("AES =" + new String (result);} catch (Exception e) {e. printStackTrace ();}}}

Running result:

Last PBE:

Package cn.edu. hpu. pbe; import java. security. key; import java. security. secureRandom; import javax. crypto. cipher; import javax. crypto. secretKeyFactory; import javax. crypto. spec. PBEKeySpec; import javax. crypto. spec. PBEParameterSpec; public class jdk_PBE {public static final String src = "I Love You! "; Public static void main (String [] args) {jdkPBE ();} private static void jdkPBE () {try {// initialize salt SecureRandom random = new SecureRandom (); byte [] salt = random. generateSeed (8); // password and key String password = "imooc"; PBEKeySpec pbeKeySpec = new PBEKeySpec (password. toCharArray (); // generate the secret conversion object SecretKeyFactory factory = SecretKeyFactory. getInstance ("PBEWITHMD5andDES"); Key key = factory. generateSecret (pbeKeySpec); // encrypt PBEParameterSpec pbeParameterSpec = new PBEParameterSpec (salt, 100); // instantiate an input material of the PBE object: the parameters are "salt and iterations" Cipher cipher = Cipher. getInstance ("PBEWITHMD5andDES"); cipher. init (Cipher. ENCRYPT_MODE, key, pbeParameterSpec); byte [] result = cipher. doFinal (src. getBytes (); System. out. println ("PBE:" + result. toString (); // decrypt cipher. init (Cipher. DECRYPT_MODE, key, pbeParameterSpec); result = cipher. doFinal (result); System. out. println ("PBE:" + new String (result);} catch (Exception e) {e. printStackTrace ();}}}

Running result:

For the above four methods, PBE is a safer encryption method, which determines the encryption result by salt and password. Which of the above is a better method even if you want to introduce the symmetric encryption method.