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  • Java使用RSA加密解密签名及校验

    概述

    由于项目要用到非对称加密解密签名校验什么的,于是参考《Java加密解密的艺术》写一个RSA进行加密解密签名及校验的Demo,代码很简单,特此分享!

    详细

    由于项目要用到非对称加密解密签名校验什么的,于是参考《Java加密解密的艺术》写一个RSA进行加密解密签名及校验的Demo,代码很简单,特此分享!

    一、项目截图

    代码下载后,导入到eclipse中,如下:

    image.png

    运行MainTest类即可。

    二、具体代码类

    RSA加密解密类:

    package com.ihep;
    import java.io.BufferedReader;  
    import java.io.BufferedWriter;  
    import java.io.FileReader;  
    import java.io.FileWriter;  
    import java.io.IOException;  
    import java.security.InvalidKeyException;  
    import java.security.KeyFactory;  
    import java.security.KeyPair;  
    import java.security.KeyPairGenerator;  
    import java.security.NoSuchAlgorithmException;  
    import java.security.SecureRandom;  
      
    import java.security.interfaces.RSAPrivateKey;  
    import java.security.interfaces.RSAPublicKey;  
    import java.security.spec.InvalidKeySpecException;  
    import java.security.spec.PKCS8EncodedKeySpec;  
    import java.security.spec.X509EncodedKeySpec;  
      
    import javax.crypto.BadPaddingException;  
    import javax.crypto.Cipher;  
    import javax.crypto.IllegalBlockSizeException;  
    import javax.crypto.NoSuchPaddingException;  
      
    public class RSAEncrypt {  
        /** 
         * 字节数据转字符串专用集合 
         */  
        private static final char[] HEX_CHAR = { '0', '1', '2', '3', '4', '5', '6',  
                '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };  
      
        /** 
         * 随机生成密钥对 
         */  
        public static void genKeyPair(String filePath) {  
            // KeyPairGenerator类用于生成公钥和私钥对,基于RSA算法生成对象  
            KeyPairGenerator keyPairGen = null;  
            try {  
                keyPairGen = KeyPairGenerator.getInstance("RSA");  
            } catch (NoSuchAlgorithmException e) {  
                // TODO Auto-generated catch block  
                e.printStackTrace();  
            }  
            // 初始化密钥对生成器,密钥大小为96-1024位  
            keyPairGen.initialize(1024,new SecureRandom());  
            // 生成一个密钥对,保存在keyPair中  
            KeyPair keyPair = keyPairGen.generateKeyPair();  
            // 得到私钥  
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();  
            // 得到公钥  
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  
            try {  
                // 得到公钥字符串  
                String publicKeyString = Base64.encode(publicKey.getEncoded());  
                // 得到私钥字符串  
                String privateKeyString = Base64.encode(privateKey.getEncoded());  
                // 将密钥对写入到文件  
                FileWriter pubfw = new FileWriter(filePath + "/publicKey.keystore");  
                FileWriter prifw = new FileWriter(filePath + "/privateKey.keystore");  
                BufferedWriter pubbw = new BufferedWriter(pubfw);  
                BufferedWriter pribw = new BufferedWriter(prifw);  
                pubbw.write(publicKeyString);  
                pribw.write(privateKeyString);  
                pubbw.flush();  
                pubbw.close();  
                pubfw.close();  
                pribw.flush();  
                pribw.close();  
                prifw.close();  
            } catch (Exception e) {  
                e.printStackTrace();  
            }  
        }  
      
        /** 
         * 从文件中输入流中加载公钥 
         *  
         * @param in 
         *            公钥输入流 
         * @throws Exception 
         *             加载公钥时产生的异常 
         */  
        public static String loadPublicKeyByFile(String path) throws Exception {  
            try {  
                BufferedReader br = new BufferedReader(new FileReader(path  
                        + "/publicKey.keystore"));  
                String readLine = null;  
                StringBuilder sb = new StringBuilder();  
                while ((readLine = br.readLine()) != null) {  
                    sb.append(readLine);  
                }  
                br.close();  
                return sb.toString();  
            } catch (IOException e) {  
                throw new Exception("公钥数据流读取错误");  
            } catch (NullPointerException e) {  
                throw new Exception("公钥输入流为空");  
            }  
        }  
      
        /** 
         * 从字符串中加载公钥 
         *  
         * @param publicKeyStr 
         *            公钥数据字符串 
         * @throws Exception 
         *             加载公钥时产生的异常 
         */  
        public static RSAPublicKey loadPublicKeyByStr(String publicKeyStr)  
                throws Exception {  
            try {  
                byte[] buffer = Base64.decode(publicKeyStr);  
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
                X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);  
                return (RSAPublicKey) keyFactory.generatePublic(keySpec);  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此算法");  
            } catch (InvalidKeySpecException e) {  
                throw new Exception("公钥非法");  
            } catch (NullPointerException e) {  
                throw new Exception("公钥数据为空");  
            }  
        }  
      
        /** 
         * 从文件中加载私钥 
         *  
         * @param keyFileName 
         *            私钥文件名 
         * @return 是否成功 
         * @throws Exception 
         */  
        public static String loadPrivateKeyByFile(String path) throws Exception {  
            try {  
                BufferedReader br = new BufferedReader(new FileReader(path  
                        + "/privateKey.keystore"));  
                String readLine = null;  
                StringBuilder sb = new StringBuilder();  
                while ((readLine = br.readLine()) != null) {  
                    sb.append(readLine);  
                }  
                br.close();  
                return sb.toString();  
            } catch (IOException e) {  
                throw new Exception("私钥数据读取错误");  
            } catch (NullPointerException e) {  
                throw new Exception("私钥输入流为空");  
            }  
        }  
      
        public static RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr)  
                throws Exception {  
            try {  
                byte[] buffer = Base64.decode(privateKeyStr);  
                PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);  
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
                return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此算法");  
            } catch (InvalidKeySpecException e) {  
                throw new Exception("私钥非法");  
            } catch (NullPointerException e) {  
                throw new Exception("私钥数据为空");  
            }  
        }  
      
        /** 
         * 公钥加密过程 
         *  
         * @param publicKey 
         *            公钥 
         * @param plainTextData 
         *            明文数据 
         * @return 
         * @throws Exception 
         *             加密过程中的异常信息 
         */  
        public static byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData)  
                throws Exception {  
            if (publicKey == null) {  
                throw new Exception("加密公钥为空, 请设置");  
            }  
            Cipher cipher = null;  
            try {  
                // 使用默认RSA  
                cipher = Cipher.getInstance("RSA");  
                // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
                cipher.init(Cipher.ENCRYPT_MODE, publicKey);  
                byte[] output = cipher.doFinal(plainTextData);  
                return output;  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此加密算法");  
            } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
                return null;  
            } catch (InvalidKeyException e) {  
                throw new Exception("加密公钥非法,请检查");  
            } catch (IllegalBlockSizeException e) {  
                throw new Exception("明文长度非法");  
            } catch (BadPaddingException e) {  
                throw new Exception("明文数据已损坏");  
            }  
        }  
      
        /** 
         * 私钥加密过程 
         *  
         * @param privateKey 
         *            私钥 
         * @param plainTextData 
         *            明文数据 
         * @return 
         * @throws Exception 
         *             加密过程中的异常信息 
         */  
        public static byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData)  
                throws Exception {  
            if (privateKey == null) {  
                throw new Exception("加密私钥为空, 请设置");  
            }  
            Cipher cipher = null;  
            try {  
                // 使用默认RSA  
                cipher = Cipher.getInstance("RSA");  
                cipher.init(Cipher.ENCRYPT_MODE, privateKey);  
                byte[] output = cipher.doFinal(plainTextData);  
                return output;  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此加密算法");  
            } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
                return null;  
            } catch (InvalidKeyException e) {  
                throw new Exception("加密私钥非法,请检查");  
            } catch (IllegalBlockSizeException e) {  
                throw new Exception("明文长度非法");  
            } catch (BadPaddingException e) {  
                throw new Exception("明文数据已损坏");  
            }  
        }  
      
        /** 
         * 私钥解密过程 
         *  
         * @param privateKey 
         *            私钥 
         * @param cipherData 
         *            密文数据 
         * @return 明文 
         * @throws Exception 
         *             解密过程中的异常信息 
         */  
        public static byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData)  
                throws Exception {  
            if (privateKey == null) {  
                throw new Exception("解密私钥为空, 请设置");  
            }  
            Cipher cipher = null;  
            try {  
                // 使用默认RSA  
                cipher = Cipher.getInstance("RSA");  
                // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
                cipher.init(Cipher.DECRYPT_MODE, privateKey);  
                byte[] output = cipher.doFinal(cipherData);  
                return output;  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此解密算法");  
            } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
                return null;  
            } catch (InvalidKeyException e) {  
                throw new Exception("解密私钥非法,请检查");  
            } catch (IllegalBlockSizeException e) {  
                throw new Exception("密文长度非法");  
            } catch (BadPaddingException e) {  
                throw new Exception("密文数据已损坏");  
            }  
        }  
      
        /** 
         * 公钥解密过程 
         *  
         * @param publicKey 
         *            公钥 
         * @param cipherData 
         *            密文数据 
         * @return 明文 
         * @throws Exception 
         *             解密过程中的异常信息 
         */  
        public static byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData)  
                throws Exception {  
            if (publicKey == null) {  
                throw new Exception("解密公钥为空, 请设置");  
            }  
            Cipher cipher = null;  
            try {  
                // 使用默认RSA  
                cipher = Cipher.getInstance("RSA");  
                // cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());  
                cipher.init(Cipher.DECRYPT_MODE, publicKey);  
                byte[] output = cipher.doFinal(cipherData);  
                return output;  
            } catch (NoSuchAlgorithmException e) {  
                throw new Exception("无此解密算法");  
            } catch (NoSuchPaddingException e) {  
                e.printStackTrace();  
                return null;  
            } catch (InvalidKeyException e) {  
                throw new Exception("解密公钥非法,请检查");  
            } catch (IllegalBlockSizeException e) {  
                throw new Exception("密文长度非法");  
            } catch (BadPaddingException e) {  
                throw new Exception("密文数据已损坏");  
            }  
        }  
      
        /** 
         * 字节数据转十六进制字符串 
         *  
         * @param data 
         *            输入数据 
         * @return 十六进制内容 
         */  
        public static String byteArrayToString(byte[] data) {  
            StringBuilder stringBuilder = new StringBuilder();  
            for (int i = 0; i < data.length; i++) {  
                // 取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移  
                stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]);  
                // 取出字节的低四位 作为索引得到相应的十六进制标识符  
                stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);  
                if (i < data.length - 1) {  
                    stringBuilder.append(' ');  
                }  
            }  
            return stringBuilder.toString();  
        }  
    }


    签名及校验类:

    package com.ihep;
    import java.security.KeyFactory;  
    import java.security.PrivateKey;  
    import java.security.PublicKey;  
    import java.security.spec.PKCS8EncodedKeySpec;  
    import java.security.spec.X509EncodedKeySpec;  
      
    /** 
     * RSA签名验签类 
     */  
    public class RSASignature{  
          
        /** 
         * 签名算法 
         */  
        public static final String SIGN_ALGORITHMS = "SHA1WithRSA";  
      
        /** 
        * RSA签名 
        * @param content 待签名数据 
        * @param privateKey 商户私钥 
        * @param encode 字符集编码 
        * @return 签名值 
        */  
        public static String sign(String content, String privateKey, String encode)  
        {  
            try   
            {  
                PKCS8EncodedKeySpec priPKCS8    = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );   
                  
                KeyFactory keyf                 = KeyFactory.getInstance("RSA");  
                PrivateKey priKey               = keyf.generatePrivate(priPKCS8);  
      
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);  
      
                signature.initSign(priKey);  
                signature.update( content.getBytes(encode));  
      
                byte[] signed = signature.sign();  
                  
                return Base64.encode(signed);  
            }  
            catch (Exception e)   
            {  
                e.printStackTrace();  
            }  
              
            return null;  
        }  
          
        public static String sign(String content, String privateKey)  
        {  
            try   
            {  
                PKCS8EncodedKeySpec priPKCS8    = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );   
                KeyFactory keyf = KeyFactory.getInstance("RSA");  
                PrivateKey priKey = keyf.generatePrivate(priPKCS8);  
                java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);  
                signature.initSign(priKey);  
                signature.update( content.getBytes());  
                byte[] signed = signature.sign();  
                return Base64.encode(signed);  
            }  
            catch (Exception e)   
            {  
                e.printStackTrace();  
            }  
            return null;  
        }  
          
        /** 
        * RSA验签名检查 
        * @param content 待签名数据 
        * @param sign 签名值 
        * @param publicKey 分配给开发商公钥 
        * @param encode 字符集编码 
        * @return 布尔值 
        */  
        public static boolean doCheck(String content, String sign, String publicKey,String encode)  
        {  
            try   
            {  
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
                byte[] encodedKey = Base64.decode(publicKey);  
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));  
      
              
                java.security.Signature signature = java.security.Signature  
                .getInstance(SIGN_ALGORITHMS);  
              
                signature.initVerify(pubKey);  
                signature.update( content.getBytes(encode) );  
              
                boolean bverify = signature.verify( Base64.decode(sign) );  
                return bverify;  
                  
            }   
            catch (Exception e)   
            {  
                e.printStackTrace();  
            }  
              
            return false;  
        }  
          
        public static boolean doCheck(String content, String sign, String publicKey)  
        {  
            try   
            {  
                KeyFactory keyFactory = KeyFactory.getInstance("RSA");  
                byte[] encodedKey = Base64.decode(publicKey);  
                PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));  
      
                java.security.Signature signature = java.security.Signature  
                .getInstance(SIGN_ALGORITHMS);  
              
                signature.initVerify(pubKey);  
                signature.update( content.getBytes() );  
              
                boolean bverify = signature.verify( Base64.decode(sign) );  
                return bverify;  
                  
            }   
            catch (Exception e)   
            {
                e.printStackTrace();  
            }
              
            return false;  
        }  
          
    }

    再来一个Base64的类,当然你也可以用commons-codec-1.9.jar

    package com.ihep;  
      
    public final class Base64 {  
      
        static private final int     BASELENGTH           = 128;  
        static private final int     LOOKUPLENGTH         = 64;  
        static private final int     TWENTYFOURBITGROUP   = 24;  
        static private final int     EIGHTBIT             = 8;  
        static private final int     SIXTEENBIT           = 16;  
        static private final int     FOURBYTE             = 4;  
        static private final int     SIGN                 = -128;  
        static private final char    PAD                  = '=';  
        static private final boolean fDebug               = false;  
        static final private byte[]  base64Alphabet       = new byte[BASELENGTH];  
        static final private char[]  lookUpBase64Alphabet = new char[LOOKUPLENGTH];  
      
        static {  
            for (int i = 0; i < BASELENGTH; ++i) {  
                base64Alphabet[i] = -1;  
            }  
            for (int i = 'Z'; i >= 'A'; i--) {  
                base64Alphabet[i] = (byte) (i - 'A');  
            }  
            for (int i = 'z'; i >= 'a'; i--) {  
                base64Alphabet[i] = (byte) (i - 'a' + 26);  
            }  
      
            for (int i = '9'; i >= '0'; i--) {  
                base64Alphabet[i] = (byte) (i - '0' + 52);  
            }  
      
            base64Alphabet['+'] = 62;  
            base64Alphabet['/'] = 63;  
      
            for (int i = 0; i <= 25; i++) {  
                lookUpBase64Alphabet[i] = (char) ('A' + i);  
            }  
      
            for (int i = 26, j = 0; i <= 51; i++, j++) {  
                lookUpBase64Alphabet[i] = (char) ('a' + j);  
            }  
      
            for (int i = 52, j = 0; i <= 61; i++, j++) {  
                lookUpBase64Alphabet[i] = (char) ('0' + j);  
            }  
            lookUpBase64Alphabet[62] = (char) '+';  
            lookUpBase64Alphabet[63] = (char) '/';  
      
        }  
      
        private static boolean isWhiteSpace(char octect) {  
            return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);  
        }  
      
        private static boolean isPad(char octect) {  
            return (octect == PAD);  
        }  
      
        private static boolean isData(char octect) {  
            return (octect < BASELENGTH && base64Alphabet[octect] != -1);  
        }  
      
        /** 
         * Encodes hex octects into Base64 
         * 
         * @param binaryData Array containing binaryData 
         * @return Encoded Base64 array 
         */  
        public static String encode(byte[] binaryData) {  
      
            if (binaryData == null) {  
                return null;  
            }  
      
            int lengthDataBits = binaryData.length * EIGHTBIT;  
            if (lengthDataBits == 0) {  
                return "";  
            }  
      
            int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;  
            int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;  
            int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1 : numberTriplets;  
            char encodedData[] = null;  
      
            encodedData = new char[numberQuartet * 4];  
      
            byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;  
      
            int encodedIndex = 0;  
            int dataIndex = 0;  
            if (fDebug) {  
                System.out.println("number of triplets = " + numberTriplets);  
            }  
      
            for (int i = 0; i < numberTriplets; i++) {  
                b1 = binaryData[dataIndex++];  
                b2 = binaryData[dataIndex++];  
                b3 = binaryData[dataIndex++];  
      
                if (fDebug) {  
                    System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3);  
                }  
      
                l = (byte) (b2 & 0x0f);  
                k = (byte) (b1 & 0x03);  
      
                byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);  
                byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);  
                byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);  
      
                if (fDebug) {  
                    System.out.println("val2 = " + val2);  
                    System.out.println("k4   = " + (k << 4));  
                    System.out.println("vak  = " + (val2 | (k << 4)));  
                }  
      
                encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f];  
            }  
      
            // form integral number of 6-bit groups  
            if (fewerThan24bits == EIGHTBIT) {  
                b1 = binaryData[dataIndex];  
                k = (byte) (b1 & 0x03);  
                if (fDebug) {  
                    System.out.println("b1=" + b1);  
                    System.out.println("b1<<2 = " + (b1 >> 2));  
                }  
                byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[k << 4];  
                encodedData[encodedIndex++] = PAD;  
                encodedData[encodedIndex++] = PAD;  
            } else if (fewerThan24bits == SIXTEENBIT) {  
                b1 = binaryData[dataIndex];  
                b2 = binaryData[dataIndex + 1];  
                l = (byte) (b2 & 0x0f);  
                k = (byte) (b1 & 0x03);  
      
                byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);  
                byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);  
      
                encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)];  
                encodedData[encodedIndex++] = lookUpBase64Alphabet[l << 2];  
                encodedData[encodedIndex++] = PAD;  
            }  
      
            return new String(encodedData);  
        }  
      
        /** 
         * Decodes Base64 data into octects 
         * 
         * @param encoded string containing Base64 data 
         * @return Array containind decoded data. 
         */  
        public static byte[] decode(String encoded) {  
      
            if (encoded == null) {  
                return null;  
            }  
      
            char[] base64Data = encoded.toCharArray();  
            // remove white spaces  
            int len = removeWhiteSpace(base64Data);  
      
            if (len % FOURBYTE != 0) {  
                return null;//should be divisible by four  
            }  
      
            int numberQuadruple = (len / FOURBYTE);  
      
            if (numberQuadruple == 0) {  
                return new byte[0];  
            }  
      
            byte decodedData[] = null;  
            byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;  
            char d1 = 0, d2 = 0, d3 = 0, d4 = 0;  
      
            int i = 0;  
            int encodedIndex = 0;  
            int dataIndex = 0;  
            decodedData = new byte[(numberQuadruple) * 3];  
      
            for (; i < numberQuadruple - 1; i++) {  
      
                if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))  
                    || !isData((d3 = base64Data[dataIndex++]))  
                    || !isData((d4 = base64Data[dataIndex++]))) {  
                    return null;  
                }//if found "no data" just return null  
      
                b1 = base64Alphabet[d1];  
                b2 = base64Alphabet[d2];  
                b3 = base64Alphabet[d3];  
                b4 = base64Alphabet[d4];  
      
                decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);  
                decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));  
                decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);  
            }  
      
            if (!isData((d1 = base64Data[dataIndex++])) || !isData((d2 = base64Data[dataIndex++]))) {  
                return null;//if found "no data" just return null  
            }  
      
            b1 = base64Alphabet[d1];  
            b2 = base64Alphabet[d2];  
      
            d3 = base64Data[dataIndex++];  
            d4 = base64Data[dataIndex++];  
            if (!isData((d3)) || !isData((d4))) {//Check if they are PAD characters  
                if (isPad(d3) && isPad(d4)) {  
                    if ((b2 & 0xf) != 0)//last 4 bits should be zero  
                    {  
                        return null;  
                    }  
                    byte[] tmp = new byte[i * 3 + 1];  
                    System.arraycopy(decodedData, 0, tmp, 0, i * 3);  
                    tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);  
                    return tmp;  
                } else if (!isPad(d3) && isPad(d4)) {  
                    b3 = base64Alphabet[d3];  
                    if ((b3 & 0x3) != 0)//last 2 bits should be zero  
                    {  
                        return null;  
                    }  
                    byte[] tmp = new byte[i * 3 + 2];  
                    System.arraycopy(decodedData, 0, tmp, 0, i * 3);  
                    tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);  
                    tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));  
                    return tmp;  
                } else {  
                    return null;  
                }  
            } else { //No PAD e.g 3cQl  
                b3 = base64Alphabet[d3];  
                b4 = base64Alphabet[d4];  
                decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);  
                decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));  
                decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);  
      
            }  
      
            return decodedData;  
        }  
      
        /** 
         * remove WhiteSpace from MIME containing encoded Base64 data. 
         * 
         * @param data  the byte array of base64 data (with WS) 
         * @return      the new length 
         */  
        private static int removeWhiteSpace(char[] data) {  
            if (data == null) {  
                return 0;  
            }  
      
            // count characters that's not whitespace  
            int newSize = 0;  
            int len = data.length;  
            for (int i = 0; i < len; i++) {  
                if (!isWhiteSpace(data[i])) {  
                    data[newSize++] = data[i];  
                }  
            }  
            return newSize;  
        }  
    }

    最后是一个MainTest:

    package com.ihep;  
      
    public class MainTest {  
      
        public static void main(String[] args) throws Exception {  
            String filepath="E:/tmp/";  
      
            //生成公钥和私钥文件
            RSAEncrypt.genKeyPair(filepath); 
              
            System.out.println("--------------公钥加密私钥解密过程-------------------");  
            String plainText="ihep_公钥加密私钥解密";  
            //公钥加密过程  
            byte[] cipherData=RSAEncrypt.encrypt(RSAEncrypt.loadPublicKeyByStr(RSAEncrypt.loadPublicKeyByFile(filepath)),plainText.getBytes());  
            String cipher=Base64.encode(cipherData);  
            //私钥解密过程  
            byte[] res=RSAEncrypt.decrypt(RSAEncrypt.loadPrivateKeyByStr(RSAEncrypt.loadPrivateKeyByFile(filepath)), Base64.decode(cipher));  
            String restr=new String(res);  
            System.out.println("原文:"+plainText);  
            System.out.println("加密:"+cipher);  
            System.out.println("解密:"+restr);  
            System.out.println();  
              
            System.out.println("--------------私钥加密公钥解密过程-------------------");  
            plainText="ihep_私钥加密公钥解密";  
            //私钥加密过程  
            cipherData=RSAEncrypt.encrypt(RSAEncrypt.loadPrivateKeyByStr(RSAEncrypt.loadPrivateKeyByFile(filepath)),plainText.getBytes());  
            cipher=Base64.encode(cipherData);  
            //公钥解密过程  
            res=RSAEncrypt.decrypt(RSAEncrypt.loadPublicKeyByStr(RSAEncrypt.loadPublicKeyByFile(filepath)), Base64.decode(cipher));  
            restr=new String(res);  
            System.out.println("原文:"+plainText);  
            System.out.println("加密:"+cipher);  
            System.out.println("解密:"+restr);  
            System.out.println();  
              
            System.out.println("---------------私钥签名过程------------------");  
            String content="ihep_这是用于签名的原始数据";  
            String signstr=RSASignature.sign(content,RSAEncrypt.loadPrivateKeyByFile(filepath));  
            System.out.println("签名原串:"+content);  
            System.out.println("签名串:"+signstr);  
            System.out.println();  
              
            System.out.println("---------------公钥校验签名------------------");  
            System.out.println("签名原串:"+content);  
            System.out.println("签名串:"+signstr);  
              
            System.out.println("验签结果:"+RSASignature.doCheck(content, signstr, RSAEncrypt.loadPublicKeyByFile(filepath)));  
            System.out.println();  
              
        }  
    }

    三、运行效果

    在 E盘 建立一个tmp目录。然后运行 MainTest类(该类有main方法)。

    1、自动生成公钥和私钥文件:

    image.png

    2、eclipse控制台输出信息如下:

    image.png

    注:本文著作权归作者,由demo大师发表,拒绝转载,转载需要作者授权

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  • 原文地址:https://www.cnblogs.com/demodashi/p/8458113.html
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