RSA Encryption Decryption

Http://files.cnblogs.com/files/liuJava/rsa.zip,

Directly on the tool class JAR and the foreground JS are in the link above

Package My.tools.security;import Java.io.file;import Java.io.fileinputstream;import java.io.FileOutputStream; Import Java.io.objectinputstream;import Java.io.objectoutputstream;import Java.math.biginteger;import Java.security.keypair;import Java.security.keyfactory;import Java.security.keypairgenerator;import Java.security.provider;import Java.security.publickey;import Java.security.privatekey;import Java.security.securerandom;import Java.security.nosuchalgorithmexception;import Java.security.invalidparameterexception;import Java.security.interfaces.rsapublickey;import Java.security.interfaces.rsaprivatekey;import Java.security.spec.rsapublickeyspec;import Java.security.spec.rsaprivatekeyspec;import Java.security.spec.invalidkeyspecexception;import Javax.crypto.cipher;import Org.apache.commons.io.ioutils;import Org.apache.commons.io.fileutils;import Org.apache.commons.codec.decoderexception;import Org.apache.commons.codec.binary.hex;import Org.bouncycastle.jce.provider.BouncyCastleProviDer;import Org.slf4j.logger;import Org.slf4j.loggerfactory;import Org.apache.commons.lang.stringutils;import org.apache.commons.lang.time.dateformatutils;/** * RSA algorithm encryption/Decryption tool class. * * @author Fuchun * @version 1.0.0, 2010-05-05 */public abstract class Rsautils {private static final Logger Logger    = Loggerfactory.getlogger (Rsautils.class);    /** algorithm name */private static final String Algorithom = "RSA"; /** Save the file name of the generated key pair.    */private static final String Rsa_pair_filename = "/__rsa_pair.txt";    /** Key size */private static final int key_size = 1024;    /** Default Security Service provider */private static final Provider Default_provider = new Bouncycastleprovider ();    private static Keypairgenerator Keypairgen = null;    private static keyfactory keyfactory = null; /** the cached key pair.    */private static KeyPair Onekeypair = null;    private static File rsapairfile = null;            static {try {Keypairgen = keypairgenerator.getinstance (Algorithom, Default_provider); Keyfactory= Keyfactory.getinstance (Algorithom, Default_provider);        } catch (NoSuchAlgorithmException ex) {Logger.error (Ex.getmessage ());    } rsapairfile = new File (Getrsapairfilepath ());     Private Rsautils () {}/** * generates and returns an RSA key pair. */private static synchronized KeyPair Generatekeypair () {try {keypairgen.initialize (key_size, new            SecureRandom (Dateformatutils.format ("YyyyMMdd"). GetBytes ());            Onekeypair = Keypairgen.generatekeypair ();            Savekeypair (Onekeypair);        return onekeypair; } catch (Invalidparameterexception ex) {Logger.error ("Keypairgenerator does not support a key length of" + KE        Y_size + ".", ex); } catch (NullPointerException ex) {Logger.error ("Rsautils#key_pair_gen is null, can not generate Keypairgenera        Tor instance. ", ex);    } return null;     }/** * Returns the path of the generated/read key pair file. */private static String GETRSAPAIRFIlepath () {String URLPath = RSAUtils.class.getResource ("/"). GetPath ();    Return (new File (URLPath). GetParent () + rsa_pair_filename);     }/** * If you need to create a new key pair file, return {@code true}, otherwise {@code false}.        */Private static Boolean Iscreatekeypairfile () {//whether to create a new key pair file, Boolean createnewkeypair = false;        if (!rsapairfile.exists () | | rsapairfile.isdirectory ()) {Createnewkeypair = true;    } return Createnewkeypair;     /** * Saves the specified RSA key pair as a file.     * * @param keyPair the key pair to be saved.        */private static void Savekeypair (KeyPair KeyPair) {FileOutputStream fos = null;        ObjectOutputStream oos = null;            try {fos = Fileutils.openoutputstream (rsapairfile);            Oos = new ObjectOutputStream (FOS);        Oos.writeobject (KeyPair);        } catch (Exception ex) {ex.printstacktrace ();            } finally {ioutils.closequietly (oos);        ioutils.closequietly (FOS);}}/** * Returns the RSA key pair.  */public static KeyPair Getkeypair () {///first determine if a new key pair file needs to be regenerated if (Iscreatekeypairfile ()) {//            Directly forces the key pair file to be generated and stored in the cache.        return Generatekeypair ();        } if (Onekeypair! = null) {return onekeypair;    } return Readkeypair ();        }//synchronously read out the saved key pair private static KeyPair Readkeypair () {FileInputStream FIS = null;        ObjectInputStream ois = null;            try {fis = Fileutils.openinputstream (rsapairfile);            OIS = new ObjectInputStream (FIS);            Onekeypair = (KeyPair) ois.readobject ();        return onekeypair;        } catch (Exception ex) {ex.printstacktrace ();            } finally {ioutils.closequietly (OIS);        ioutils.closequietly (FIS);    } return null;     /** * Constructs an RSA-specific public key object based on a given coefficient and a dedicated exponent.     * * @param modulus coefficient.     * @param publicexponent Special index.     * @return RSA private Public Key object. */PublIC Static Rsapublickey Generatersapublickey (byte[] modulus, byte[] publicexponent) {Rsapublickeyspec PublicKeySpec        = new Rsapublickeyspec (new BigInteger (modulus), new BigInteger (publicexponent));        try {return (Rsapublickey) keyfactory.generatepublic (PUBLICKEYSPEC);        } catch (Invalidkeyspecexception ex) {Logger.error ("Rsapublickeyspec is unavailable.", ex); } catch (NullPointerException ex) {Logger.error ("rsautils#key_factory is null, can not generate Keyfactory ins        Tance. ", ex);    } return null;     /** * Constructs an RSA private key object based on the given coefficients and the dedicated exponent.     * * @param modulus coefficient.     * @param privateexponent Special index.     * @return RSA private Key object.  */public static Rsaprivatekey Generatersaprivatekey (byte[] modulus, byte[] privateexponent) {Rsaprivatekeyspec        Privatekeyspec = new Rsaprivatekeyspec (new BigInteger (modulus), new BigInteger (privateexponent)); try {return (Rsaprivatekey) keyfactory.generateprivate (PRIVATEKEYSPEC);        } catch (Invalidkeyspecexception ex) {Logger.error ("Rsaprivatekeyspec is unavailable.", ex); } catch (NullPointerException ex) {Logger.error ("rsautils#key_factory is null, can not generate Keyfactory ins        Tance. ", ex);    } return null;     /** * Constructs an RSA private key object based on a given 16-factor and a dedicated exponential string.     * * @param modulus coefficient.     * @param privateexponent Special index.     * @return RSA private Key object. */public static Rsaprivatekey Getrsaprivatekey (String hexmodulus, String hexprivateexponent) {if (stringutils.i Sblank (hexmodulus) | | Stringutils.isblank (hexprivateexponent)) {if (logger.isdebugenabled ()) {Logger.debug ("Hexmodulu S and hexprivateexponent cannot be empty.            Rsaprivatekey value is a null to return. ");        return null;        } byte[] modulus = null;        byte[] privateexponent = null; try {modulus = hex.deCodehex (Hexmodulus.tochararray ());        Privateexponent = Hex.decodehex (Hexprivateexponent.tochararray ()); } catch (Decoderexception ex) {logger.error ("Hexmodulus or hexprivateexponent value is invalid.        return null (Rsaprivatekey). "); if (modulus = null && privateexponent! = null) {return Generatersaprivatekey (modulus, privateexponent)        ;    } return null;     /** * Constructs an RSA-specific public key object based on a given 16-factor and a dedicated exponential string.     * * @param modulus coefficient.     * @param publicexponent Special index.     * @return RSA private Public Key object. */public static Rsapublickey Getrsapublidkey (String hexmodulus, String hexpublicexponent) {if (STRINGUTILS.ISBL Ank (hexmodulus) | |  Stringutils.isblank (hexpublicexponent)) {if (logger.isdebugenabled ()) {Logger.debug ("Hexmodulus And hexpublicexponent cannot be empty.            return null (Rsapublickey). ");        return null;        } byte[] modulus = null; byte[] publicexponent = null;            try {modulus = Hex.decodehex (Hexmodulus.tochararray ());        Publicexponent = Hex.decodehex (Hexpublicexponent.tochararray ()); } catch (Decoderexception ex) {logger.error ("Hexmodulus or hexpublicexponent value is invalid.        return null (Rsapublickey). ");        if (modulus! = NULL && publicexponent! = null) {return Generatersapublickey (modulus, publicexponent);    } return null;     /** * Encrypts data using the specified public key.     * * @param publickey the given public key.     * @param data to be encrypted.     * @return the encrypted data. */public static byte[] Encrypt (PublicKey publickey, byte[] data) throws Exception {Cipher ci = Cipher.getinsta        NCE (Algorithom, Default_provider);        Ci.init (Cipher.encrypt_mode, PublicKey);    return ci.dofinal (data);     /** * Decrypts data using the specified private key.     * * @param privatekey the given private key.     * @param data to decrypt.     * @return the original data. */public static byte[] Decrypt (PrivaTekey Privatekey, byte[] data) throws Exception {Cipher ci = cipher.getinstance (Algorithom, Default_provider);        Ci.init (Cipher.decrypt_mode, Privatekey);    return ci.dofinal (data);     /** * Encrypts the given string with the given public key.     * <p/> * If {@code PublicKey} is {@code null}, or {@code plaintext} is {@code null} then return {@code * null}.     * * @param publickey the given public key.     * @param plaintext string.     * @return ciphertext for a given string. */public static String encryptstring (PublicKey publickey, string plaintext) {if (PublicKey = null | | plaintex        T = = null) {return null;        } byte[] data = Plaintext.getbytes ();            try {byte[] En_data = Encrypt (publickey, data);        return new String (Hex.encodehex (en_data));        } catch (Exception ex) {Logger.error (Ex.getcause (). GetMessage ());    } return null;     /** * Encrypts the given string with the default public key. * <p/> * If {@code plaintext} is {@code null} then return {@code NULL}.     * * @param plaintext string.     * @return ciphertext for a given string.        */public static String encryptstring (string plaintext) {if (plaintext = = null) {return null;        } byte[] data = Plaintext.getbytes ();        KeyPair KeyPair = Getkeypair ();            try {byte[] En_data = Encrypt ((rsapublickey) keypair.getpublic (), data);        return new String (Hex.encodehex (en_data));        } catch (NullPointerException ex) {logger.error ("KeyPair cannot be null.");        } catch (Exception ex) {Logger.error (Ex.getcause (). GetMessage ());    } return null;     /** * Decrypts the given string with the given private key.     * <p/> * Returns {@code null} if the private key is {@code null}, or {@code null} or an empty string {@code Encrypttext}.     * Returns {@code null} when the private key does not match.     * * @param privatekey the given private key.     * @param encrypttext ciphertext.     * @return the original string. */public static string decryptstring (Privatekey Privatekey, string encrypttext) {if (Privatekey = =null | |        Stringutils.isblank (Encrypttext)) {return null;            } try {byte[] En_data = Hex.decodehex (Encrypttext.tochararray ());            byte[] data = Decrypt (Privatekey, en_data);        return new String (data); } catch (Exception ex) {Logger.error (String.Format ("\"%s\ "decryption failed.        Cause:%s ", Encrypttext, Ex.getcause (). GetMessage ()));    } return null;     /** * Decrypts the given string using the default private key.     * <p/> * Returns {@code null} if {@code Encrypttext} is {@code null} or an empty string.     * Returns {@code null} when the private key does not match.     * * @param encrypttext ciphertext.     * @return the original string. */public static String decryptstring (string encrypttext) {if (Stringutils.isblank (Encrypttext)) {RE        Turn null;        } KeyPair KeyPair = Getkeypair ();            try {byte[] En_data = Hex.decodehex (Encrypttext.tochararray ());            byte[] data = Decrypt ((Rsaprivatekey) keypair.getprivate (), en_data); REturn new String (data);        } catch (NullPointerException ex) {logger.error ("KeyPair cannot be null."); } catch (Exception ex) {Logger.error (String.Format ("\"%s\ "decryption failed.        Cause:%s ", Encrypttext, Ex.getmessage ()));    } return null;     /** * uses the default private key to decrypt strings that are encrypted by JS encryption (using the public key provided by this class).     * * @param encrypttext ciphertext.     * @return The original string of {@code Encrypttext}.        */public static string Decryptstringbyjs (String encrypttext) {string text = decryptstring (encrypttext);        if (text = = null) {return null;    } return Stringutils.reverse (text); /** returns the default public key that has been initialized.        */public static Rsapublickey Getdefaultpublickey () {KeyPair KeyPair = Getkeypair ();        if (KeyPair! = null) {return (Rsapublickey) keypair.getpublic ();    } return null; /** returns the default private key that has been initialized. */public static Rsaprivatekey Getdefaultprivatekey () {KeyPair KeyPair = Getkeypair();        if (KeyPair! = null) {return (Rsaprivatekey) keypair.getprivate ();    } return null; }}

　　

Use the following: or directly in the Java test:

public static void Main (string[] args) {Rsapublickey PublicKey = Rsautils.getdefaultpublickey ();        char[] Encodehex = Hex.encodehex (Publickey.getpublicexponent (). Tobytearray ());        string exponent = new String (Encodehex);        char[] EncodeHex2 = Hex.encodehex (Publickey.getmodulus (). Tobytearray ());        String Modulus=new string (ENCODEHEX2);        String encryptstring = rsautils.encryptstring (publickey, "Hello Ah ah ah");        System.out.println (encryptstring);           String decryptstringbyjs = Rsautils.decryptstringbyjs (encryptstring);        char[] Chararray = Decryptstringbyjs.tochararray ();        String resultstring = "";         for (int i=chararray.length-1; i>=0; i--) {             resultstring + = Chararray[i];           }         System.out.println (resultstring);           }

When encrypting some data that needs to be encrypted in a Web project

Background distribution secret key

Rsapublickey PublicKey = Rsautils.getdefaultpublickey ();        char[] Encodehex = Hex.encodehex (Publickey.getpublicexponent (). Tobytearray ());        string exponent = new String (Encodehex);        Actioncontext.getcontext (). Put ("exponent", exponent);         Actioncontext.getcontext (). put ("modulus", New String (Hex.encodehex (Publickey.getmodulus (). Tobytearray ())));

　　

Demonstrates the process of JS request background key

function DLs () {///These 2 are the requested    var modulus = $ ("#modulus"). Val (), exponent = $ ("#exponentid"). Val (); var key = Rsaut Ils.getkeypair (Exponent, "", modulus);p wd2 = rsautils.encryptedstring (Key, $ ("#passwordid"). Val ()); $ ("#passwordid") . Val (pwd2) document.getElementById ("Formid"). Submit ();   }

The process of background decryption

Decryption: Password = rsautils.decryptstringbyjs (password);

　　

RSA Encryption Decryption