使用java 的keytool產生RSA 公開金鑰 私密金鑰 （含代碼驗證）

keytool的使用
keytool程式由JDK提供，可以產生、查看認證和key.而keystore是key的容器，可以容納多個key及相關資訊。
每一條key由一個別名alias引用。可以把keystore中的key匯出為認證檔案.cer。顯然，用keytool產生的.cer
是未經CA簽名的認證。

添加一個Key

keytool -genkey -alias acosta -keyalg RSA -keysize 1024 -keystore acosta.keystore

查看keystore中所有的Key

keytool -list -keystore acosta.keystore

查看keystore中指定的一條記錄

keytool -list -v -alias acosta -keystore acosta.keystore

將keystore中的key匯出成認證檔案

keytool -list -v -alias acosta -keystore acosta.keystore  -export -file acosta.cer

使用java代碼驗證

 代碼如下

RSAUtil.java

package com.cn.costa.testdemo.RSA;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.IOException;import java.security.Key;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.KeyStore;import java.security.PrivateKey;import java.security.PublicKey;import java.security.Signature;import java.security.cert.Certificate;import java.security.cert.CertificateFactory;import java.security.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;import javax.crypto.Cipher;/** * <p> * RSA公開金鑰/私密金鑰/簽名工具包 * </p> * <p> * * </p> * <p> * 字串格式的密鑰在未在特殊說明情況下都為BASE64編碼格式<br/> * 由於非對稱式加密速度極其緩慢，一般檔案不使用它來加密而是使用對稱式加密，<br/> * 非對稱式加密演算法可以用來對對稱式加密的祕密金鑰加密，這樣保證密鑰的安全也就保證了資料的安全 * </p> *  * @author wechart * @date 2016-4-26 * @version 1.0 */public class RSAUtils {    public static final String KEY_ALGORITHM = "RSA";                   //密碼編譯演算法RSA    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";      //簽名演算法    private static final String PUBLIC_KEY = "RSAPublicKey";            //擷取公開金鑰的KEY    private static final String PRIVATE_KEY = "RSAPrivateKey";          //擷取私密金鑰的KEY    private static final int MAX_ENCRYPT_BLOCK = 117;                   //RSA最大加密明文大小    private static final int MAX_DECRYPT_BLOCK = 128;                   //RSA最大解密密文大小    /**      * <p>     * 產生金鑰組(公開金鑰和私密金鑰)     * </p>     *      * @return     * @throws Exception     */    public static Map<String, Object> genKeyPair() throws Exception {        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);        keyPairGen.initialize(1024);        KeyPair keyPair = keyPairGen.generateKeyPair();        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();        Map<String, Object> keyMap = new HashMap<String, Object>(2);        keyMap.put(PUBLIC_KEY, publicKey);        keyMap.put(PRIVATE_KEY, privateKey);        return keyMap;    }    /**     * <p>     * 用私密金鑰對資訊產生數位簽章     * </p>     *      * @param data 已加密資料     * @param privateKey 私密金鑰(BASE64編碼)     *      * @return     * @throws Exception     */    public static String sign(byte[] data, String privateKey) throws Exception {        byte[] keyBytes = Base64Utils.decode(privateKey);        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);        signature.initSign(privateK);        signature.update(data);        return Base64Utils.encode(signature.sign());    }    /**     * <p>     * 校正數位簽章     * </p>     *      * @param data 已加密資料     * @param publicKey 公開金鑰(BASE64編碼)     * @param sign 數位簽章     *      * @return     * @throws Exception     *      */    public static boolean verify(byte[] data, String publicKey, String sign)            throws Exception {        byte[] keyBytes = Base64Utils.decode(publicKey);        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        PublicKey publicK = keyFactory.generatePublic(keySpec);        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);        signature.initVerify(publicK);        signature.update(data);        return signature.verify(Base64Utils.decode(sign));    }    /** *//**     * <P>     * 私密金鑰解密     * </p>     *      * @param encryptedData 已加密資料     * @param privateKey 私密金鑰(BASE64編碼)     * @return     * @throws Exception     */    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)            throws Exception {        byte[] keyBytes = Base64Utils.decode(privateKey);        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());        cipher.init(Cipher.DECRYPT_MODE, privateK);        int inputLen = encryptedData.length;        ByteArrayOutputStream out = new ByteArrayOutputStream();        int offSet = 0;        byte[] cache;        int i = 0;        // 對資料分段解密        while (inputLen - offSet > 0) {            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);            } else {                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);            }            out.write(cache, 0, cache.length);            i++;            offSet = i * MAX_DECRYPT_BLOCK;        }        byte[] decryptedData = out.toByteArray();        out.close();        return decryptedData;    }    /** *//**     * <p>     * 公開金鑰解密     * </p>     *      * @param encryptedData 已加密資料     * @param publicKey 公開金鑰(BASE64編碼)     * @return     * @throws Exception     */    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)            throws Exception {        byte[] keyBytes = Base64Utils.decode(publicKey);        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        Key publicK = keyFactory.generatePublic(x509KeySpec);        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());        cipher.init(Cipher.DECRYPT_MODE, publicK);        int inputLen = encryptedData.length;        ByteArrayOutputStream out = new ByteArrayOutputStream();        int offSet = 0;        byte[] cache;        int i = 0;        // 對資料分段解密        while (inputLen - offSet > 0) {            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);            } else {                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);            }            out.write(cache, 0, cache.length);            i++;            offSet = i * MAX_DECRYPT_BLOCK;        }        byte[] decryptedData = out.toByteArray();        out.close();        return decryptedData;    }    /** *//**     * <p>     * 公開金鑰加密     * </p>     *      * @param data 來源資料     * @param publicKey 公開金鑰(BASE64編碼)     * @return     * @throws Exception     */    public static byte[] encryptByPublicKey(byte[] data, String publicKey)            throws Exception {        byte[] keyBytes = Base64Utils.decode(publicKey);        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        Key publicK = keyFactory.generatePublic(x509KeySpec);        // 對資料加密        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());        cipher.init(Cipher.ENCRYPT_MODE, publicK);        int inputLen = data.length;        ByteArrayOutputStream out = new ByteArrayOutputStream();        int offSet = 0;        byte[] cache;        int i = 0;        // 對資料分段加密        while (inputLen - offSet > 0) {            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);            } else {                cache = cipher.doFinal(data, offSet, inputLen - offSet);            }            out.write(cache, 0, cache.length);            i++;            offSet = i * MAX_ENCRYPT_BLOCK;        }        byte[] encryptedData = out.toByteArray();        out.close();        return encryptedData;    }    /**     * <p>     * 私密金鑰加密     * </p>     *      * @param data 來源資料     * @param privateKey 私密金鑰(BASE64編碼)     * @return     * @throws Exception     */    public static byte[] encryptByPrivateKey(byte[] data, String privateKey)            throws Exception {        byte[] keyBytes = Base64Utils.decode(privateKey);        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());        cipher.init(Cipher.ENCRYPT_MODE, privateK);        int inputLen = data.length;        ByteArrayOutputStream out = new ByteArrayOutputStream();        int offSet = 0;        byte[] cache;        int i = 0;        // 對資料分段加密        while (inputLen - offSet > 0) {            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);            } else {                cache = cipher.doFinal(data, offSet, inputLen - offSet);            }            out.write(cache, 0, cache.length);            i++;            offSet = i * MAX_ENCRYPT_BLOCK;        }        byte[] encryptedData = out.toByteArray();        out.close();        return encryptedData;    }    /**     * <p>     * 擷取私密金鑰     * </p>     *      * @param keyMap 金鑰組     * @return     * @throws Exception     */    public static String getPrivateKey(Map<String, Object> keyMap)            throws Exception {        Key key = (Key) keyMap.get(PRIVATE_KEY);        return Base64Utils.encode(key.getEncoded());    }    /**     * <p>     * 擷取公開金鑰     * </p>     *      * @param keyMap 金鑰組     * @return     * @throws Exception     */    public static String getPublicKey(Map<String, Object> keyMap)            throws Exception {        Key key = (Key) keyMap.get(PUBLIC_KEY);        return Base64Utils.encode(key.getEncoded());    }   public static PublicKey loadPublicKeyByFile(String filepath) throws Exception {         try {             //通過認證,擷取公開金鑰           CertificateFactory cf = CertificateFactory.getInstance("X.509");           Certificate c = cf.generateCertificate(new FileInputStream(filepath));           PublicKey publicKey = c.getPublicKey();           return publicKey;       } catch (IOException e) {             throw new Exception("公開金鑰資料流讀取錯誤");         } catch (NullPointerException e) {             throw new Exception("公開金鑰輸入資料流為空白");         }     }   public static PrivateKey loadPrivateKeyByFile(String filepath, String alias, String password) throws Exception {        try {           KeyStore ks= KeyStore.getInstance("JKS");           ks.load(new FileInputStream(filepath), password.toCharArray());                         PrivateKey privateKey = (PrivateKey)ks.getKey(alias, password.toCharArray());               return privateKey;       } catch (IOException e) {           throw new Exception("私密金鑰資料讀取錯誤");       } catch (NullPointerException e) {           throw new Exception("私密金鑰輸入資料流為空白");       }   }    public static void main(String[] args){        String serverAlias = "";        String clientAlias = "acosta";        String serverPassword = "";        String clientPassword = "acosta";//      String serverPrivateKey = "d:\\server.keystore";//      String serverPublicKey = "d:\\server.cer";          String clientPrivateKey = "E:\\TestCER\\RSATest04\\acosta.keystore";        String clientPublicKey = "E:\\TestCER\\RSATest04\\acosta.cer";  //      //      String serverPublicString = "";//      String serverPrivateString = "";        String clientPublicString = "";        String clientPrivateString = "";        String orgString = "{\"ret\":\"0\",\"ExpireTime\":\"2015/10/28 23:59:59\",\"rettxt\":\"OK\",\"Token\":\"69296128A59798E2D423D3B1A9F766F4\"}'";        String encryptString = "";        String decryptString = "";//      RSAPublicKey srvPubKey = null;        RSAPublicKey cltPubKey = null;//      RSAPrivateKey srvPriKey = null;        RSAPrivateKey cltPriKey = null;        try{                    //1- 用戶端公開金鑰                  cltPubKey = (RSAPublicKey) RSAUtils.loadPublicKeyByFile(clientPublicKey);            //2- 用戶端私密金鑰            cltPriKey = (RSAPrivateKey) RSAUtils.loadPrivateKeyByFile(clientPrivateKey, clientAlias, clientPassword);//          //3- 服務端公開金鑰//          srvPubKey = (RSAPublicKey) RSAUtils.loadPublicKeyByFile(serverPublicKey);//          //          //4- 服務端私密金鑰//          srvPriKey = (RSAPrivateKey) RSAUtils.loadPrivateKeyByFile(serverPrivateKey, serverAlias, serverPassword);            System.out.println("\nclientPublicString:\n"+Base64Utils.encode(cltPubKey.getEncoded())+"\n");            System.out.println("\nclientPrivateString:\n"+Base64Utils.encode(cltPriKey.getEncoded())+"\n");//          System.out.println("\nserverPublicString:\n"+Base64Utils.encode(srvPubKey.getEncoded())+"\n");//          System.out.println("\nserverPrivateString:\n"+Base64Utils.encode(srvPriKey.getEncoded())+"\n");                 }catch(Exception e){            e.printStackTrace();        }//      System.out.println("\n=============================== Step-1:用戶端私密金鑰加密-服務端公開金鑰解密\n");//      //用戶端私密金鑰加密-服務端公開金鑰解密//      try{            //          byte[] data = orgString.getBytes();//          //          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(cltPriKey.getEncoded()));            //          encryptString = new String(encodedData);            //          //          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(srvPubKey.getEncoded()));//          decryptString = new String(decodedData);//          //          System.out.println("orginalString:"+orgString);//          System.out.println("encrypString:"+encryptString);//          System.out.println("decryptString:"+decryptString); //      }catch(Exception e){//          System.err.println("Step-1 解密失敗!");//      }//      //      System.out.println("\n=============================== Step-2:服務端私密金鑰加密-用戶端公開金鑰解密\n");//      //服務端私密金鑰加密-用戶端公開金鑰解密//      try{//          //          //          byte[] data = orgString.getBytes();//          //          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(srvPriKey.getEncoded()));            //          encryptString = new String(encodedData);        //          //          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(cltPubKey.getEncoded()));//          decryptString = new String(decodedData);//          //          System.out.println("orginalString:"+orgString);//          System.out.println("encrypString:"+encryptString);//          System.out.println("decryptString:"+decryptString); //      }catch(Exception e){//          System.err.println("Step-2 解密失敗!");//      }        System.out.println("\n=============================== Step-3:用戶端私密金鑰加密-用戶端公開金鑰解密\n");        String orgString2 = "";        //用戶端私密金鑰加密-用戶端公開金鑰解密        try{                        byte[] data = orgString.getBytes();            byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(cltPriKey.getEncoded()));                        encryptString = new String(encodedData);                        byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(cltPubKey.getEncoded()));            decryptString = new String(decodedData);            System.out.println("orginalString:"+orgString);            System.out.println("encrypString:"+encryptString);            System.out.println("decryptString:"+decryptString);         }catch(Exception e){            System.err.println("Step-3  解密失敗!");        }//      //      System.out.println("\n=============================== Step-4:服務端私密金鑰加密-服務端公開金鑰解密\n");//      //服務端私密金鑰加密-服務端公開金鑰解密//      try{            //          //          byte[] data = orgString.getBytes();//          //          byte[] encodedData = RSAUtils.encryptByPrivateKey(data, Base64Utils.encode(srvPriKey.getEncoded()));            //          encryptString = new String(encodedData);        //          //          byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, Base64Utils.encode(srvPubKey.getEncoded()));//          decryptString = new String(decodedData);//          //          System.out.println("orginalString:"+orgString);//          System.out.println("encrypString:"+encryptString);//          System.out.println("decryptString:"+decryptString); //      }catch(Exception e){//          System.err.println("Step-4 解密失敗!");//      }//             }}

Base64Utils

package com.cn.costa.testdemo.RSA;import java.