Java encryption and decryption-AES symmetric encryption algorithm

Package COM. jadyer. util. codec; import Java. security. key; import javax. crypto. cipher; import javax. crypto. keygenerator; import javax. crypto. secretkey; import javax. crypto. spec. secretkeyspec; import Org. apache. commons. codec. binary. base64; /*** AES symmetric encryption algorithm * @ see ============================== ========================================================== ================================================================= *@ see demonstrates the implementation of java6.0, bouncycast Of course Le also supports the AES symmetric encryption algorithm * @ see. In addition, we can use the AES algorithm implementation as a reference to complete RC2, implementation of RC4 and blowfish algorithms * @ see ================================ ========================================================== ================================================================= * @ see because des is insecure and desede is inefficient, as a result, the AES algorithm (Advanced Encryption Standard) * @ see is faster than DES, with high security, short key creation time, high sensitivity, and low memory requirements, widely used in various fields * @ see currently, AES algorithms are usually used in mobile communication systems and security shells of some software, some wireless routers also use the AES algorithm to construct the encryption protocol * @ see ========================== = ========================================================== ========================================================== * @ See because java6.0 supports most algorithms, however, due to exit restrictions, the key length cannot meet the requirements * @ see. Therefore, note that if you use a 256-bit key, therefore, there is no policy restriction file (unlimited strength jurisdiction policy files) * @ see. However, Sun restricts the permission file local_poblicy.jar and us_export_policy.jar. We can download the replacement file on the sun official website, remove restrictions * @ see URL for http://www.oracle.com/technetwork/java/javase/downloads/index.html * @ see find Java at the bottom of the page Cryptography Extension (JCE) unlimited strength jurisdiction policy files 6, click to download * @ see http://download.oracle.com/otn-pub/java/jce_policy/6/jce_policy-6.zip * @ see http://download.oracle.com/otn-pub/java/jce/7/UnlimitedJCEPolicyJDK7.zip * @ see and then overwrite the files in the security directory under the Local JDK directory and JRE directory * @ see ======== ========================================================== ========================================================== ===============================* @ s EE for more information about AES, you can refer to this blog http://blog.csdn.net/kongqz/article/category/800296 * @ create Jul 17,201 2 6:35:36 * @ author Xuan Yu (http://blog.csdn/net/jadyer) */public class aescodec {// key algorithm public static final string key_algorithm = "AES"; // encryption/decryption algorithm/working mode/filling mode. java6.0 supports the pkcs5padding filling mode, bouncycastle supports the pkcs7padding filling mode public static final string cipher_algorithm = "AEs/ECB/pkcs5padding";/*** generate key */Public stat IC string initkey () throws exception {keygenerator kg = keygenerator. getinstance (key_algorithm); // instantiate the key generator kg. init (128); // initialize the key generator: AES requires that the key length be 128,192,256-bit secretkey = kg. generatekey (); // generate the key return base64.encodebase64string (secretkey. getencoded (); // obtain the binary key encoding form}/*** convert key */public static key Tokey (byte [] Key) throws exception {return New secretkeyspec (key, key_algorithm);}/*** encrypt data ** @ par Am data to be encrypted * @ Param key * @ return encrypted data */public static string encrypt (string data, string key) throws exception {key K = Tokey (base64.decodebase64 (key); // restore the key // use the pkcs7padding filling method, so you have to write it here (that is, call the bouncycastle component) // cipher = cipher. getinstance (cipher_algorithm, "BC"); cipher = cipher. getinstance (cipher_algorithm); // instantiate the cipher object, which is used to complete the actual encryption operation cipher. init (cipher. encrypt_mode, k); // initial Initialize the cipher object and set it to the encryption mode return base64.encodebase64string (Cipher. dofinal (data. getbytes (); // perform the encryption operation. Encrypted results are usually transmitted in base64 encoding.}/***** decrypt data * @ Param data to be decrypted data * @ Param key * @ return decrypted data **/ public static string decrypt (string data, string key) throws exception {key K = Tokey (base64.decodebase64 (key); cipher = cipher. getinstance (cipher_algorithm); cipher. init (cipher. decrypt_mode, k); // initialize the cipher object and set it to the decryption mode return new string (cipher. dofinal (base64.decodebase64 (data); // execute the decryption operation} public static Vo Id main (string [] ARGs) throws exception {string source = "standing on the cloud, knocking on the keyboard and looking at the window leading to the other end of the world, only for those who read 0 and 1 .. "; System. out. println ("Original:" + source); string key = initkey (); system. out. println ("key:" + key); string encryptdata = encrypt (source, key); system. out. println ("encryption:" + encryptdata); string decryptdata = decrypt (encryptdata, key); system. out. println ("decryption:" + decryptdata );}}