JDK self-bringing method for message digest operation

Ah, a little bit of comment, too lazy to introduce, put a code bar, to understand the effect can be.

1  PackageJdbc.pro.lin;2 3 Importjava.security.InvalidKeyException;4 Importjava.security.MessageDigest;5 Importjava.security.NoSuchAlgorithmException;6 7 ImportJavax.crypto.KeyGenerator;8 ImportJavax.crypto.Mac;9 ImportJavax.crypto.SecretKey;Ten ImportJavax.crypto.spec.SecretKeySpec; One  A Importorg.apache.commons.codec.binary.Base64; -  -  Public classMymessagedigest { the      Public Static FinalString Plain_text = "I m a sample"; -      Public Static FinalString md_algorithm = "MD5"; -      Public Static FinalString sha_algorithm = "SHA-512"; -      Public Static FinalString mac_algorithm = "HmacSHA512"; +  -      Public Static voidMain (string[] args) { +System.out.println ("MD5:" +MD5 (Plain_text.getbytes ())); ASystem.out.println ("SHA-512:" +SHA (Plain_text.getbytes ())); atSystem.out.println ("HmacSHA512:" +MAC (Plain_text.getbytes ())); -     } -  -     /** - * 1. Message digest algorithm, MD family, with MD2 MD4 MD5, where MD4 JDK does not support -      *  in      * @paramplaintext -      * @return to      */ +      Public StaticString MD5 (byte[] plaintext) { - messagedigest messagedigest; the         Try { *MessageDigest =messagedigest.getinstance (md_algorithm); $             returnbase64.encodebase64string (Messagedigest.digest (plaintext));Panax Notoginseng}Catch(nosuchalgorithmexception e) { -             //TODO auto-generated Catch block the e.printstacktrace (); +         } A         return NULL; the  +     } -  $     /** $ * 2.SHA security hash Algorithm secure Hash algorithm, fixed length summary information SHA-1 SHA-2 (SHA-224 - * SHA-256 SHA-384 SHA-512) is still used MessageDigest class, JDK does not support 224 -      *  the      * @paramplaintext -      * @returnWuyi      */ the      Public StaticString SHA (byte[] plaintext) { - messagedigest messagedigest; Wu         Try { -MessageDigest =messagedigest.getinstance (sha_algorithm); About             returnbase64.encodebase64string (Messagedigest.digest (plaintext)); $}Catch(Exception e) { - e.printstacktrace (); -         } -         return NULL; A     } +  the     /** - * 3.MAC (Message authentication code) message authentication code algorithm, is contains the key hash function algorithm.  $ * Features of MD and SHA are compatible.  the * The encryption process is three steps away, similar to the symmetric and asymmetric cryptography that are described later the * 1) incoming algorithm, instantiation of an encryption device the * 2) incoming key, initialize the encryption device the * 3) Call the Dofinal method for encryption -      * @paramplaintext in      * @return the      */ the      Public StaticString MAC (byte[] plaintext) { About  the         Try { the             byte[] Secretbytes =Generatormacsecretkey (); theSecretkey key =Restoremacsecretkey (secretbytes); +Mac Mac =mac.getinstance (mac_algorithm); - Mac.init (key); the             returnbase64.encodebase64string (mac.dofinal (plaintext));Bayi}Catch(NoSuchAlgorithmException |invalidkeyexception e) { the             //TODO auto-generated Catch block the e.printstacktrace (); -         } -         return NULL; the  the     } the  the     /** - * Mac generates a random key two-step walk 1. Create a Keygenerator 2. Call the Keygenerator.generatekey method the      *  the      * @return the      */94      Public Static byte[] Generatormacsecretkey () { the keygenerator Keygenerator; the         Try { theKeygenerator =keygenerator.getinstance (mac_algorithm);98Secretkey key =Keygenerator.generatekey (); About             returnkey.getencoded (); -}Catch(nosuchalgorithmexception e) {101             //TODO auto-generated Catch block102 e.printstacktrace ();103         }104         return NULL; the     }106 107     /**108 * Restore Key109      *  the      * @paramsecretbytes111      * @return the      */113      Public StaticSecretkey Restoremacsecretkey (byte[] secretbytes) { theSecretkey key =NewSecretkeyspec (secretbytes, mac_algorithm); the         returnkey; the     }117}

JDK self-bringing method for message digest operation