AES symmetric encryption and decryption

 Packagedemo.security;Importjava.io.IOException;Importjava.io.UnsupportedEncodingException;Importjava.security.InvalidKeyException;Importjava.security.NoSuchAlgorithmException;ImportJava.security.SecureRandom;Importjava.util.Base64;ImportJava.util.Scanner;Importjavax.crypto.BadPaddingException;ImportJavax.crypto.Cipher;Importjavax.crypto.IllegalBlockSizeException;ImportJavax.crypto.KeyGenerator;Importjavax.crypto.NoSuchPaddingException;ImportJavax.crypto.SecretKey;ImportJavax.crypto.spec.SecretKeySpec;ImportSun.misc.BASE64Decoder;ImportSun.misc.BASE64Encoder;/** AES symmetric encryption and decryption*/ Public classSymmetricencoder {/** Encryption * 1. Construct key Generator * 2. Initialize the key generator according to the Ecnoderules rule * 3. Generate the key * 4. Create and initialize the cipher * 5. Content encryption * 6. Return string*/     Public Staticstring Aesencode (string encoderules,string content) {Try {            //1. Construct key generator, specified as AES algorithm, case insensitiveKeygenerator keygen=keygenerator.getinstance ("AES"); //2. Initialize the key generator according to the ecnoderules rule//generates a 128-bit random source, based on the array of bytes passed inKeygen.init (128,NewSecureRandom (Encoderules.getbytes ())); //3. Generating the original symmetric keySecretkey original_key=Keygen.generatekey (); //4. Byte array to obtain the original symmetric key            byte[] raw=original_key.getencoded (); //5. Generating an AES key based on a byte arraySecretkey key=NewSecretkeyspec (Raw, "AES"); //6. AES Self-forming cipher according to the specified algorithmCipher cipher=cipher.getinstance ("AES"); //7. Initialize the cipher, the first parameter is an encryption (Encrypt_mode) or decryption/decryption (Decrypt_mode) operation, the second parameter is the key usedCipher.init (Cipher.encrypt_mode, key); //8. Get a byte array of encrypted content (set to utf-8 here) otherwise the content will be decrypted as garbled if Chinese and English are mixed.            byte[] Byte_encode=content.getbytes ("Utf-8"); //9. Depending on how the cipher is initialized-encryption: Encrypt the data            byte[] byte_aes=cipher.dofinal (Byte_encode); //10. Convert the encrypted data to a string//It's not going to find a package in Base64encoder.//Workaround://in the project's build path, remove the JRE system library, add the Library JRE system Library, and then all is fine after recompiling. String aes_encode=NewString (NewBase64encoder (). Encode (Byte_aes)); //11. Return a string            returnAes_encode; } Catch(nosuchalgorithmexception e) {e.printstacktrace (); } Catch(nosuchpaddingexception e) {e.printstacktrace (); } Catch(InvalidKeyException e) {e.printstacktrace (); } Catch(illegalblocksizeexception e) {e.printstacktrace (); } Catch(badpaddingexception e) {e.printstacktrace (); } Catch(unsupportedencodingexception e) {e.printstacktrace (); }                //if wrong, add nulll .        return NULL; }    /** Decryption * decryption Process: * 1. Encrypt with 1-4 step * 2. Convert the encrypted string back to byte[] array * 3. Decrypt encrypted content*/     Public Staticstring Aesdncode (string encoderules,string content) {Try {            //1. Construct key generator, specified as AES algorithm, case insensitiveKeygenerator keygen=keygenerator.getinstance ("AES"); //2. Initialize the key generator according to the ecnoderules rule//generates a 128-bit random source, based on the array of bytes passed inKeygen.init (128,NewSecureRandom (Encoderules.getbytes ())); //3. Generating the original symmetric keySecretkey original_key=Keygen.generatekey (); //4. Byte array to obtain the original symmetric key            byte[] raw=original_key.getencoded (); //5. Generating an AES key based on a byte arraySecretkey key=NewSecretkeyspec (Raw, "AES"); //6. AES Self-forming cipher according to the specified algorithmCipher cipher=cipher.getinstance ("AES"); //7. Initialize the cipher, the first parameter is an encryption (Encrypt_mode) or decryption (Decrypt_mode) operation, the second parameter is the key usedCipher.init (Cipher.decrypt_mode, key); //8. Decode the encrypted and encoded content into a byte array            byte[] byte_content=NewBase64decoder (). Decodebuffer (content); /** Decryption*/            byte[] Byte_decode=cipher.dofinal (byte_content); String Aes_decode=NewString (Byte_decode, "Utf-8"); returnAes_decode; } Catch(nosuchalgorithmexception e) {e.printstacktrace (); } Catch(nosuchpaddingexception e) {e.printstacktrace (); } Catch(InvalidKeyException e) {e.printstacktrace (); } Catch(IOException e) {e.printstacktrace (); } Catch(illegalblocksizeexception e) {e.printstacktrace (); } Catch(badpaddingexception e) {e.printstacktrace (); }                //if wrong, add nulll .        return NULL; }         Public Static voidMain (string[] args) {symmetricencoder se=NewSymmetricencoder (); Scanner Scanner=NewScanner (system.in); /** Encryption*/System.out.println ("Use AES symmetric encryption, enter the rules for encryption"); String Encoderules=Scanner.next (); System.out.println ("Please enter what you want to encrypt:"); String content=Scanner.next (); System.out.println ("According to the rules entered" +encoderules+ "encrypted ciphertext is:" +SE.               Aesencode (encoderules, content)); /** Decryption*/System.out.println ("Symmetric decryption using AES, enter the encryption rule: (must be the same as encryption)"); Encoderules=Scanner.next (); System.out.println ("Please enter the content to decrypt (ciphertext):"); Content=Scanner.next (); System.out.println ("According to the input rule" +encoderules+ "decrypted plaintext is:" +SE.    Aesdncode (encoderules, content)); }}

Test results:

using AES symmetric encryption, enter an encrypted rule using AES symmetric encryption enter what you want to encrypt: encryption using AES symmetric encryption based on the rules entered using AES symmetric encryption is: Z0NWRNPHGHGXHN0CQJLS58YCJHMCBFER33RWS7LW+ay= use AES symmetric decryption, enter the encryption rule: (must be the same as encryption) use AES symmetric encryption Please enter the content to decrypt (ciphertext): Z0NWRNPHGHGXHN0CQJLS58YCJHMCBFER33RWS7LW+ay= decrypted plaintext using AES symmetric encryption according to the rules entered is: Symmetric encryption using AES

AES symmetric encryption and decryption