加密证书和RSA加密解密

最近一直在做与第三方的支付业务，因为数据涉及到了钱，所以交互的数据保密性非常的重要！主要应用的是RSA加密机制，整理一下共享给大家！
1、生成加密证书

1）产生证书的工具：openssl；openssl的官方推荐网站下载：http://slproweb.com/products/Win32OpenSSL.html

2）配置文件：我下载的是win-64位轻量版的：Win64OpenSSL-1_0_2f.exe，下载之后解压到C盘（我刚开始是解压到其他盘的，但是出现错误：can’t open config file: /usr/local/ssl/openssl.cnf，有人说配置环境变量：set OPENSSL_CONF=..\conf\openssl.cnf ；我是了不好使，大家查出来是什么问题可以告诉我一下，哈哈）在C盘根目录依次建立usr/local/ssl/openssl.cnf文件后，下载地址：http://download.csdn.net/detail/qq_32347977/9396321

3）生成采用des3算法保护的私钥：
OpenSSL> genrsa -des3 -out private-rsa.key 1024
命令执行过程中的提示信息Enter pass phrase 的含义是输入用来保护私钥文件的密码（不要超过6位），我的是123456。

4） 生成公钥证书：
OpenSSL> req -new -x509 -key private-rsa.key -days 750 -out public-rsa.cer
该过程除了最开始时需要输入私钥文件的保护密码之外，其他需要的输入均可直接回车忽略，不影响正常使用。

5）生成PKCS12 格式Keystore：
OpenSSL> pkcs12 -export -name test-alias -in public-rsa.cer -inkey private-rsa.key -out user-rsa.pfx

这样就ok了。

AES工具类：

package com.alex.util;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class AES {

    public static final String CHAR_ENCODING = "UTF-8";
    public static final String AES_ALGORITHM = "AES/ECB/PKCS5Padding";
     /**
     * 加密
     * 
     * @param / data
     *            待加密密内容
     * @param /key
     *            加密密钥
     * @return
     */
    public static byte[] encrypt(byte[] data, byte[] key) {
        if(key.length!=16){
            throw new RuntimeException("Invalid AES key length (must be 16 bytes)");
        }
        try {
            SecretKeySpec secretKey = new SecretKeySpec(key, "AES"); 
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec seckey = new SecretKeySpec(enCodeFormat,"AES");
            Cipher cipher = Cipher.getInstance(AES_ALGORITHM);// 创建密码器
            cipher.init(Cipher.ENCRYPT_MODE, seckey);// 初始化
            byte[] result = cipher.doFinal(data);
            return result; // 加密
        } catch (Exception e){
            throw new RuntimeException("encrypt fail!", e);
        }
    }

    /**
     * 解密
     * 
     * @param / content
     *            待解密内容
     * @param /password
     *            解密密钥
     * @return
     */
    public static byte[] decrypt(byte[] data, byte[] key) {
        if(key.length!=16){
            throw new RuntimeException("Invalid AES key length (must be 16 bytes)");
        }
        try {
            SecretKeySpec secretKey = new SecretKeySpec(key, "AES"); 
            byte[] enCodeFormat = secretKey.getEncoded();
            SecretKeySpec seckey = new SecretKeySpec(enCodeFormat, "AES");
            Cipher cipher = Cipher.getInstance(AES_ALGORITHM);// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, seckey);// 初始化
            byte[] result = cipher.doFinal(data);
            return result; // 加密
        } catch (Exception e){
            throw new RuntimeException("decrypt fail!", e);
        }
    }

    public static String encryptToBase64(String data, String key){
        try {
            byte[] valueByte = encrypt(data.getBytes(CHAR_ENCODING), key.getBytes(CHAR_ENCODING));
            return new String(Base64.encode(valueByte));
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("encrypt fail!", e);
        }

    }

    public static String decryptFromBase64(String data, String key){
        try {
            byte[] originalData = Base64.decode(data.getBytes());
            byte[] valueByte = decrypt(originalData, key.getBytes(CHAR_ENCODING));
            return new String(valueByte, CHAR_ENCODING);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("decrypt fail!", e);
        }
    }

    public static String encryptWithKeyBase64(String data, String key){
        try {
            byte[] valueByte = encrypt(data.getBytes(CHAR_ENCODING), Base64.decode(key.getBytes()));
            return new String(Base64.encode(valueByte));
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("encrypt fail!", e);
        }
    }

    public static String decryptWithKeyBase64(String data, String key){
        try {
            byte[] originalData = Base64.decode(data.getBytes());
            byte[] valueByte = decrypt(originalData, Base64.decode(key.getBytes()));
            return new String(valueByte, CHAR_ENCODING);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("decrypt fail!", e);
        }
    }

    public static byte[] genarateRandomKey(){
        KeyGenerator keygen = null;
        try {
            keygen = KeyGenerator.getInstance(AES_ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(" genarateRandomKey fail!", e);
        }
        SecureRandom random = new SecureRandom();
        keygen.init(random);
        Key key = keygen.generateKey();
        return key.getEncoded();
    }

    public static String genarateRandomKeyWithBase64(){
        return new String(Base64.encode(genarateRandomKey()));
    }
}

Base64工具类：

package com.alex.util;

import java.io.UnsupportedEncodingException;

public class Base64  {
    /**
     * Chunk size per RFC 2045 section 6.8.
     *
     * 
The {@value} character limit does not count the trailing CRLF, but counts
     * all other characters, including any equal signs.
     *
     * @see RFC 2045 section 6.8
     */
    static final int CHUNK_SIZE = 76;

    /**
     * Chunk separator per RFC 2045 section 2.1.
     *
     * @see RFC 2045 section 2.1
     */
    static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();

    /**
     * The base length.
     */
    static final int BASELENGTH = 255;

    /**
     * Lookup length.
     */
    static final int LOOKUPLENGTH = 64;

    /**
     * Used to calculate the number of bits in a byte.
     */
    static final int EIGHTBIT = 8;

    /**
     * Used when encoding something which has fewer than 24 bits.
     */
    static final int SIXTEENBIT = 16;

    /**
     * Used to determine how many bits data contains.
     */
    static final int TWENTYFOURBITGROUP = 24;

    /**
     * Used to get the number of Quadruples.
     */
    static final int FOURBYTE = 4;

    /**
     * Used to test the sign of a byte.
     */
    static final int SIGN = -128;

    /**
     * Byte used to pad output.
     */
    static final byte PAD = (byte) '=';

    // Create arrays to hold the base64 characters and a
    // lookup for base64 chars
    private static byte[] base64Alphabet = new byte[BASELENGTH];
    private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

    // Populating the lookup and character arrays
    static {
        for (int i = 0; i < BASELENGTH; i++) {
            base64Alphabet[i] = (byte) -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] = (byte) ('A' + i);
        }

        for (int i = 26, j = 0; i <= 51; i++, j++) {
            lookUpBase64Alphabet[i] = (byte) ('a' + j);
        }

        for (int i = 52, j = 0; i <= 61; i++, j++) {
            lookUpBase64Alphabet[i] = (byte) ('0' + j);
        }

        lookUpBase64Alphabet[62] = (byte) '+';
        lookUpBase64Alphabet[63] = (byte) '/';
    }

    private static boolean isBase64(byte octect) {
        if (octect == PAD) {
            return true;
        } else if (base64Alphabet[octect] == -1) {
            return false;
        } else {
            return true;
        }
    }

    /**
     * Tests a given byte array to see if it contains
     * only valid characters within the Base64 alphabet.
     *
     * @param arrayOctect byte array to test
     * @return true if all bytes are valid characters in the Base64
     *         alphabet or if the byte array is empty; false, otherwise
     */
    public static boolean isArrayByteBase64(byte[] arrayOctect) {

        arrayOctect = discardWhitespace(arrayOctect);

        int length = arrayOctect.length;
        if (length == 0) {
            // shouldn't a 0 length array be valid base64 data?
            // return false;
            return true;
        }
        for (int i = 0; i < length; i++) {
            if (!isBase64(arrayOctect[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Encodes binary data using the base64 algorithm but
     * does not chunk the output.
     *
     * @param binaryData binary data to encode
     * @return Base64 characters
     */
    public static byte[] encodeBase64(byte[] binaryData) {
        return encodeBase64(binaryData, false);
    }

    /**
     * Encodes binary data using the base64 algorithm and chunks
     * the encoded output into 76 character blocks
     *
     * @param binaryData binary data to encode
     * @return Base64 characters chunked in 76 character blocks
     */
    public static byte[] encodeBase64Chunked(byte[] binaryData) {
        return encodeBase64(binaryData, true);
    }

    /**
     * Decodes a byte[] containing containing
     * characters in the Base64 alphabet.
     *
     * @param pArray A byte array containing Base64 character data
     * @return a byte array containing binary data
     */
    public static byte[] decode(byte[] pArray) {
        return decodeBase64(pArray);
    }

    /**
     * Encodes binary data using the base64 algorithm, optionally
     * chunking the output into 76 character blocks.
     *
     * @param binaryData Array containing binary data to encode.
     * @param isChunked if isChunked is true this encoder will chunk
     *                  the base64 output into 76 character blocks
     * @return Base64-encoded data.
     */
    public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
        int lengthDataBits = binaryData.length * EIGHTBIT;
        int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
        int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
        byte encodedData[] = null;
        int encodedDataLength = 0;
        int nbrChunks = 0;

        if (fewerThan24bits != 0) {
            //data not divisible by 24 bit
            encodedDataLength = (numberTriplets + 1) * 4;
        } else {
            // 16 or 8 bit
            encodedDataLength = numberTriplets * 4;
        }

        // If the output is to be "chunked" into 76 character sections,
        // for compliance with RFC 2045 MIME, then it is important to
        // allow for extra length to account for the separator(s)
        if (isChunked) {

            nbrChunks =
                (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
            encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
        }

        encodedData = new byte[encodedDataLength];

        byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

        int encodedIndex = 0;
        int dataIndex = 0;
        int i = 0;
        int nextSeparatorIndex = CHUNK_SIZE;
        int chunksSoFar = 0;

        //log.debug("number of triplets = " + numberTriplets);
        for (i = 0; i < numberTriplets; i++) {
            dataIndex = i * 3;
            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            b3 = binaryData[dataIndex + 2];

            //log.debug("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);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            //log.debug( "val2 = " + val2 );
            //log.debug( "k4   = " + (k<<4) );
            //log.debug(  "vak  = " + (val2 | (k<<4)) );
            encodedData[encodedIndex + 1] =
                lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] =
                lookUpBase64Alphabet[(l << 2) | val3];
            encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];

            encodedIndex += 4;

            // If we are chunking, let's put a chunk separator down.
            if (isChunked) {
                // this assumes that CHUNK_SIZE % 4 == 0
                if (encodedIndex == nextSeparatorIndex) {
                    System.arraycopy(
                        CHUNK_SEPARATOR,
                        0,
                        encodedData,
                        encodedIndex,
                        CHUNK_SEPARATOR.length);
                    chunksSoFar++;
                    nextSeparatorIndex =
                        (CHUNK_SIZE * (chunksSoFar + 1)) +
                        (chunksSoFar * CHUNK_SEPARATOR.length);
                    encodedIndex += CHUNK_SEPARATOR.length;
                }
            }
        }

        // form integral number of 6-bit groups
        dataIndex = i * 3;

        if (fewerThan24bits == EIGHTBIT) {
            b1 = binaryData[dataIndex];
            k = (byte) (b1 & 0x03);
            //log.debug("b1=" + b1);
            //log.debug("b1<<2 = " + (b1>>2) );
            byte val1 =
                ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
            encodedData[encodedIndex + 2] = PAD;
            encodedData[encodedIndex + 3] = 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 + 1] =
                lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
            encodedData[encodedIndex + 3] = PAD;
        }

        if (isChunked) {
            // we also add a separator to the end of the final chunk.
            if (chunksSoFar < nbrChunks) {
                System.arraycopy(
                    CHUNK_SEPARATOR,
                    0,
                    encodedData,
                    encodedDataLength - CHUNK_SEPARATOR.length,
                    CHUNK_SEPARATOR.length);
            }
        }

        return encodedData;
    }

    /**
     * Decodes Base64 data into octects
     *
     * @param base64Data Byte array containing Base64 data
     * @return Array containing decoded data.
     */
    public static byte[] decodeBase64(byte[] base64Data) {
        // RFC 2045 requires that we discard ALL non-Base64 characters
        base64Data = discardNonBase64(base64Data);

        // handle the edge case, so we don't have to worry about it later
        if (base64Data.length == 0) {
            return new byte[0];
        }

        int numberQuadruple = base64Data.length / FOURBYTE;
        byte decodedData[] = null;
        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;

        // Throw away anything not in base64Data

        int encodedIndex = 0;
        int dataIndex = 0;
        {
            // this sizes the output array properly - rlw
            int lastData = base64Data.length;
            // ignore the '=' padding
            while (base64Data[lastData - 1] == PAD) {
                if (--lastData == 0) {
                    return new byte[0];
                }
            }
            decodedData = new byte[lastData - numberQuadruple];
        }

        for (int i = 0; i < numberQuadruple; i++) {
            dataIndex = i * 4;
            marker0 = base64Data[dataIndex + 2];
            marker1 = base64Data[dataIndex + 3];

            b1 = base64Alphabet[base64Data[dataIndex]];
            b2 = base64Alphabet[base64Data[dataIndex + 1]];

            if (marker0 != PAD && marker1 != PAD) {
                //No PAD e.g 3cQl
                b3 = base64Alphabet[marker0];
                b4 = base64Alphabet[marker1];

                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                decodedData[encodedIndex + 1] =
                    (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
                decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
            } else if (marker0 == PAD) {
                //Two PAD e.g. 3c[Pad][Pad]
                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
            } else if (marker1 == PAD) {
                //One PAD e.g. 3cQ[Pad]
                b3 = base64Alphabet[marker0];

                decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                decodedData[encodedIndex + 1] =
                    (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            }
            encodedIndex += 3;
        }
        return decodedData;
    }

    /**
     * Discards any whitespace from a base-64 encoded block.
     *
     * @param data The base-64 encoded data to discard the whitespace
     * from.
     * @return The data, less whitespace (see RFC 2045).
     */
    static byte[] discardWhitespace(byte[] data) {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++) {
            switch (data[i]) {
            case (byte) ' ' :
            case (byte) '\n' :
            case (byte) '\r' :
            case (byte) '\t' :
                    break;
            default:
                    groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

        System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);

        return packedData;
    }

    /**
     * Discards any characters outside of the base64 alphabet, per
     * the requirements on page 25 of RFC 2045 - "Any characters
     * outside of the base64 alphabet are to be ignored in base64
     * encoded data."
     *
     * @param data The base-64 encoded data to groom
     * @return The data, less non-base64 characters (see RFC 2045).
     */
    static byte[] discardNonBase64(byte[] data) {
        byte groomedData[] = new byte[data.length];
        int bytesCopied = 0;

        for (int i = 0; i < data.length; i++) {
            if (isBase64(data[i])) {
                groomedData[bytesCopied++] = data[i];
            }
        }

        byte packedData[] = new byte[bytesCopied];

        System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);

        return packedData;
    }

    /**
     * Encodes a byte[] containing binary data, into a byte[] containing
     * characters in the Base64 alphabet.
     *
     * @param pArray a byte array containing binary data
     * @return A byte array containing only Base64 character data
     */
    public static byte[] encode(byte[] pArray) {
        return encodeBase64(pArray, false);
    }


     public static String decode(String cryptoStr) throws
       UnsupportedEncodingException {
       if(cryptoStr.length()<40)
         return "";
       try
       {
         String tempStr = new String(decode(cryptoStr.getBytes("UTF-8")));
         String result = tempStr.substring(40, tempStr.length());
         return new String(decode(result.getBytes("UTF-8")));
       }
       catch(ArrayIndexOutOfBoundsException ex)
       {
         return "";
       }
     }

     /**
      * Decodes Base64 data into octects
      *
      * @param encoded string containing Base64 data
      * @return Array containind decoded data.
      */
     public static byte[] decode2(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;
     }

     private static boolean isWhiteSpace(char octect) {
         return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
     }     

     private static boolean isData(char octect) {
         return (octect < BASELENGTH && base64Alphabet[octect] != -1);
     }

     private static boolean isPad(char octect) {
         return (octect == PAD);
     }

     /**
      * 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;
     } 
}

Decipher工具类：

package com.alex.util;

import java.security.PrivateKey;
import java.security.PublicKey;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;


public class Decipher {
    /**
     * 解密
     * 
     * @param merchant_id
     * @param data
     * @param encryptkey
     * @return
     * @throws 
     */
    public static String decryptData(Map map) throws Exception {

        String encryptkey = map.get("encryptkey");
        String data = map.get("data");

        // 获取自己私钥解密
        PrivateKey pvkformPfx = RSA.getPvkformPfx("F:\\miyao\\demo\\user-rsa.pfx",
                "123456");
        String decryptData = RSA.decrypt(encryptkey, pvkformPfx);

        String post = AES.decryptFromBase64(data, decryptData);

        return post;
    }

    /**
     * 加密
     * 
     * @param merchant_id
     * @param data
     * @param encryptkey
     * @return
     * @throws 
     */
    public static Map encryptData(String json) throws Exception {
        System.out.println("json数据=============>" + json);

        // 获取公钥
        PublicKey pubKeyFromCrt = RSA.getPubKeyFromCRT("F:\\miyao\\demo\\public-rsa.cer");
        // 随机生成16数字
        String key = getRandom(16);
        // 使用RSA算法将自己随机生成的AESkey加密
        String encryptKey = RSA.encrypt(key, pubKeyFromCrt);
        // 使用AES算法用随机生成的AESkey，对json串进行加密
        String encryData = AES.encryptToBase64(json, key);

        System.out.println("密文key============>" + encryptKey);
        System.out.println("密文数据===========>" + encryData);

        Map map = new HashMap();
        map.put("data", encryData);
        map.put("encryptkey", encryptKey);

        return map;
    }

    public static Random random = new Random();

    public static String getRandom(int length) {
        StringBuilder ret = new StringBuilder();
        for (int i = 0; i < length; i++) {
            boolean isChar = (random.nextInt(2) % 2 == 0);// 输出字母还是数字
            if (isChar) { // 字符串
                int choice = (random.nextInt(2) % 2 == 0) ? 65 : 97; // 取得大写字母还是小写字母
                ret.append((char) (choice + random.nextInt(26)));
            } else { // 数字
                ret.append(Integer.toString(random.nextInt(10)));
            }
        }
        return ret.toString();
    }

    public static void main(String[] args) {

    }

}

RSA工具类：

package com.alex.util;

/*
 --------------------------------------------**********--------------------------------------------

 该算法于1977年由美国麻省理工学院MIT(Massachusetts Institute of Technology)的Ronal Rivest，Adi Shamir和Len Adleman三位年轻教授提出，并以三人的姓氏Rivest，Shamir和Adlernan命名为RSA算法，是一个支持变长密钥的公共密钥算法，需要加密的文件快的长度也是可变的!

 所谓RSA加密算法，是世界上第一个非对称加密算法，也是数论的第一个实际应用。它的算法如下：

 1.找两个非常大的质数p和q（通常p和q都有155十进制位或都有512十进制位）并计算n=pq，k=(p-1)(q-1)。

 2.将明文编码成整数M，保证M不小于0但是小于n。

 3.任取一个整数e，保证e和k互质，而且e不小于0但是小于k。加密钥匙（称作公钥）是(e, n)。

 4.找到一个整数d，使得ed除以k的余数是1（只要e和n满足上面条件，d肯定存在）。解密钥匙（称作密钥）是(d, n)。

 加密过程： 加密后的编码C等于M的e次方除以n所得的余数。

 解密过程： 解密后的编码N等于C的d次方除以n所得的余数。

 只要e、d和n满足上面给定的条件。M等于N。

 --------------------------------------------**********--------------------------------------------
 */


import javax.crypto.Cipher;

import org.apache.commons.lang.StringUtils;

import java.io.FileInputStream;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

public class RSA {

    /** 指定key的大小 */
    private static int KEYSIZE = 1024;
    public static final String CHAR_ENCODING = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA/ECB/PKCS1Padding";
    /**
     * 生成密钥对
     */
    public static Map generateKeyPair() throws Exception {
        /** RSA算法要求有一个可信任的随机数源 */
        SecureRandom sr = new SecureRandom();
        /** 为RSA算法创建一个KeyPairGenerator对象 */
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        /** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */
        kpg.initialize(KEYSIZE, sr);
        /** 生成密匙对 */
        KeyPair kp = kpg.generateKeyPair();
        /** 得到公钥 */
        Key publicKey = kp.getPublic();
        byte[] publicKeyBytes = publicKey.getEncoded();
        String pub = new String(Base64.encodeBase64(publicKeyBytes),
                CHAR_ENCODING);
        /** 得到私钥 */
        Key privateKey = kp.getPrivate();
        byte[] privateKeyBytes = privateKey.getEncoded();
        String pri = new String(Base64.encodeBase64(privateKeyBytes),
                CHAR_ENCODING);

        Map map = new HashMap();
        map.put("publicKey", pub);
        map.put("privateKey", pri);
        RSAPublicKey rsp = (RSAPublicKey) kp.getPublic();
        BigInteger bint = rsp.getModulus();
        byte[] b = bint.toByteArray();
        byte[] deBase64Value = Base64.encodeBase64(b);
        String retValue = new String(deBase64Value);
        map.put("modulus", retValue);
        return map;
    }

    /**
     * 通过PFX文件获得私钥
     *
     * @param //文件路径
     * @param //PFX密码
     * @return PrivateKey
     */
    public static PrivateKey getPvkformPfx(String strPfx, String strPassword)
            throws Exception {
        PrivateKey prikey = null;
        char[] nPassword = null;
        if ((strPassword == null) || strPassword.trim().equals("")) {
            nPassword = null;
        } else {
            nPassword = strPassword.toCharArray();
        }
        KeyStore ks = getKsformPfx(strPfx, strPassword);
        String keyAlias = getAlsformPfx(strPfx, strPassword);
        prikey = (PrivateKey) ks.getKey(keyAlias, nPassword);
        return prikey;
    }

    /**
     * 通过PFX文件获得KEYSTORE
     *
     * @param //文件路径
     * @param //PFX密码
     * @return KeyStore
     */
    public static KeyStore getKsformPfx(String strPfx, String strPassword)
            throws Exception {
        FileInputStream fis = null;
        Security
                .addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        KeyStore ks = KeyStore.getInstance("PKCS12", "BC");
        fis = new FileInputStream(strPfx);
        // If the keystore password is empty(""), then we have to set
        // to null, otherwise it won't work!!!
        char[] nPassword = null;
        if ((strPassword == null) || strPassword.trim().equals("")) {
            nPassword = null;
        } else {
            nPassword = strPassword.toCharArray();
        }
        ks.load(fis, nPassword);
        if (null != fis) {

            fis.close();

        }
        return ks;

    }

    /**
     * 通过PFX文件获得别名
     *
     * @param  //文件路径
     * @param //PFX密码
     * @return 别名
     */
    public static String getAlsformPfx(String strPfx, String strPassword)
            throws Exception {
        String keyAlias = null;
        KeyStore ks = getKsformPfx(strPfx, strPassword);
        Enumeration enumas = ks.aliases();
        keyAlias = null;
        // we are readin just one certificate.
        if (enumas.hasMoreElements()) {
            keyAlias = (String) enumas.nextElement();
        }
        return keyAlias;
    }

    /**
     * 获取公钥
     */
    public static PublicKey getPubKeyFromCRT(String crtFileName) throws Exception {
        InputStream is = new FileInputStream(crtFileName);
        CertificateFactory cf = CertificateFactory.getInstance("x509");
        Certificate cerCert = cf.generateCertificate(is);
        return cerCert.getPublicKey();
    }

    /**
     * 加密方法 source： 源数据
     */
    public static String encrypt(String source, String publicKey)
            throws Exception {
        Key key = getPublicKey(publicKey);
        /** 得到Cipher对象来实现对源数据的RSA加密 */
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] b = source.getBytes();
        /** 执行加密操作 */
        byte[] b1 = cipher.doFinal(b);
        return new String(Base64.encodeBase64(b1),
                CHAR_ENCODING);
    }
    /**
     * 加密方法 source： 源数据
     */
    public static String encrypt(String source, PublicKey pubKeyFromCrt)
            throws Exception {
        Key key = pubKeyFromCrt;
        /** 得到Cipher对象来实现对源数据的RSA加密 */
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] b = source.getBytes();
        /** 执行加密操作 */
        byte[] b1 = cipher.doFinal(b);
        return new String(Base64.encodeBase64(b1),
                CHAR_ENCODING);
    }
    /**
     * 解密算法 cryptograph:密文
     */
    public static String decrypt(String cryptograph, PrivateKey privateKey)
            throws Exception {
        Key key = privateKey;
        /** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
        Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] b1 = Base64.decodeBase64(cryptograph.getBytes());
        /** 执行解密操作 */
        byte[] b = cipher.doFinal(b1);
        return new String(b);
    }

    /**
     * 得到公钥
     * 
     * @param key
     *            密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static PublicKey getPublicKey(String key) throws Exception {
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(
                Base64.decodeBase64(key.getBytes()));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(keySpec);
        return publicKey;
    }

    /**
     * 得到私钥
     * 
     * @param key
     *            密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static PrivateKey getPrivateKey(String key) throws Exception {
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(
                Base64.decodeBase64(key.getBytes()));
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
        return privateKey;
    }

    /**
     * 签名
     */
    public static String sign(String content, String privateKey) {
        String charset = CHAR_ENCODING;
        try {
            PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(
                    Base64.decodeBase64(privateKey.getBytes()));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);

            Signature signature = Signature.getInstance("SHA1WithRSA");

            signature.initSign(priKey);
            signature.update(content.getBytes(charset));

            byte[] signed = signature.sign();

            return new String(Base64.encodeBase64(signed));
        } catch (Exception e) {

        }

        return null;
    }

    /**
     * 验签
     */
    public static boolean checkSign(String content, String sign, String publicKey)
    {
        try 
        {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode2(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));


            Signature signature = Signature
            .getInstance("SHA1WithRSA");

            signature.initVerify(pubKey);
            signature.update( content.getBytes("utf-8") );

            boolean bverify = signature.verify( Base64.decode2(sign) );
            return bverify;

        } 
        catch (Exception e) 
        {
            e.printStackTrace();
        }

        return false;
    }   
    /**
     * 生成RSA签名
     */
    public static String handleRSA(TreeMap map,
            String privateKey) {
        StringBuffer sbuffer = new StringBuffer();
        for (Map.Entry entry : map.entrySet()) {
            sbuffer.append(entry.getValue());
        }
        String signTemp = sbuffer.toString();

        String sign = "";
        if (StringUtils.isNotEmpty(privateKey)) {
            sign = RSA.sign(signTemp, privateKey);
        }
        return sign;
    }

    /**
     * 解密算法 cryptograph:密文
     */
    public static String decrypt(String cryptograph, String privateKey)
            throws Exception {
        Key key = getPrivateKey(privateKey);
        /** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] b1 = Base64.decodeBase64(cryptograph.getBytes());
        /** 执行解密操作 */
        byte[] b = cipher.doFinal(b1);
        return new String(b);
    }

}

测试类：

package com.alex.util;

import java.util.Map;

public class RSATest {
    public static void main(String[] args) throws Exception {
        String reqStr = "加密证书和RSA加密解密";
        //加密
        Map  map = Decipher.encryptData(reqStr);

        //解密
        String respStr = Decipher.decryptData(map);
        System.out.println("解密后的数据为=============>" + respStr);
    }
}

结果：

源码下载：http://download.csdn.net/detail/qq_32347977/9444440