JAVA實現RSA簽名、驗簽

對接API接口的時候往往為了安全考慮，需要實現數據簽名和驗簽，最常用的就是使用公私鑰對進行簽名驗簽，主要流程為：

1、生成公私鑰對

2、使用私鑰進行簽名

3、使用公鑰驗證簽名

這么最的主要目的是為了保證請求來源的合法性，參數的正確性（不被篡改）

廢話不多說，直接擼出工具類，本次工具類一共3個。Rsa.java、Base64.java、BaseHelper.java。生成簽名的時候將需要傳遞的參數bean通過BaseHelper.sortParamAll(bean)轉成K=V&K1=V1......的形式，然后調用Rsa.sign()方法即可生成簽名。

驗簽的時候獲取到傳遞過來的參數json串（jsonParams），同樣將業務參數通過BaseHelper.sortCheckParam(jsonParams)轉成K=V&K1=V1......的形式（剔除sign參數），然后調用Rsa.doCheck()方法驗證簽名是否通過。

傳遞參數示例：

{
    "name": "zhangsan",
    "age": "34",
    "amont": "100.00",
    "sign": "bpy8NrCnRq8lK9wVWI0EHNJVUgEpJFWlwOIIvMOUYfflQsvRzw8gCFNLpT/0pTOHeHwB/Cn8tMmXCzv9fnm8cUXlAAofsRYOneVseGt+ArgtsXGitjACA0L3Krbn2SsG+xEL/VbMGW2UwyLHx8FNz88ZzbORSKaERPC7tL3MWpQ=",
    "time": "20170831103259"
}

 

package cn.test;

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

/**
 * RSA工具類
 * 
 */
public class Rsa {

    public static final String SIGN_ALGORITHMS = "MD5WithRSA";

    /**
     * @param content:簽名的參數內容
     * @param privateKey：私鑰
     * @return
     */
    public static String sign(String content, String privateKey) {
        String charset = "utf-8";
        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(charset));

            byte[] signed = signature.sign();

            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * @param content：驗證參數的內容
     * @param sign：簽名
     * @param publicKey：公鑰
     * @return
     */
    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("utf-8"));

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

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

        return false;
    }
}

package cn.test;

/**
 * Base64 工具類
 * 
 */
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;
    }
}

package cn.test;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

import org.apache.log4j.Logger;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * 工具類
 */
public class BaseHelper {

    private final static Logger log = Logger.getLogger(BaseHelper.class);

    public static final String PARAM_EQUAL = "=";

    public static final String PARAM_AND = "&";

    public static String toJSONString(Object obj) {
        JSONObject json = new JSONObject();
        try {
            Map<String, String> map = bean2Parameters(obj);
            for (Map.Entry<String, String> entry : map.entrySet()) {
                json.put(entry.getKey(), entry.getValue());
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return json.toString();
    }

    /**
     * 對Object進行List<NameValuePair>轉換后按key進行升序排序，以key=value&...形式返回
     * 
     * @param list
     * @return
     */
    public static String sortParam(Object order) {
        Map<String, String> map = bean2Parameters(order);
        return sortParam(map);
    }

    public static String sortParamAll(Object order) {
        Map<String, String> map = bean2Parameters(order);
        return sortCheckParam(map);
    }

    /**
     * 對Object進行List<NameValuePair>轉換后按key進行升序排序，以key=value&...形式返回
     * 
     * @param list
     * @return
     */
    public static String sortCheckParam(Map<String, String> order) {
        if (order == null) {
            return null;
        }

        Map<String, String> parameters = new TreeMap<String, String>(new Comparator<String>() {
            public int compare(String obj1, String obj2) {
                return obj1.compareToIgnoreCase(obj2);
            }
        });
        parameters.putAll(order);

        StringBuffer sb = new StringBuffer();
        for (Map.Entry<String, String> entry : parameters.entrySet()) {
            if (null != entry.getValue() && !"".equals(entry.getValue()) && !entry.getKey().equals("sign")) {
                sb.append(entry.getKey());
                sb.append(PARAM_EQUAL);
                sb.append(entry.getValue());
                sb.append(PARAM_AND);
            }
        }

        String params = sb.toString();
        if (sb.toString().endsWith(PARAM_AND)) {
            params = sb.substring(0, sb.length() - 1);
        }
        log.info("待簽名串:" + params);
        return params;
    }

    /**
     * 將bean轉換成鍵值對列表
     * 
     * @param bean
     * @return
     */
    public static Map<String, String> bean2Parameters(Object bean) {
        if (bean == null) {
            return null;
        }

        Map<String, String> parameters = new HashMap<String, String>();

        if (null != parameters) {
            // 取得bean所有public 方法
            Method[] Methods = bean.getClass().getMethods();
            for (Method method : Methods) {
                if (method != null && method.getName().startsWith("get") && !method.getName().startsWith("getClass")) {
                    // 得到屬性的類名
                    String value = "";
                    // 得到屬性值
                    try {
                        String className = method.getReturnType().getSimpleName();
                        if (className.equalsIgnoreCase("int")) {
                            int val = 0;
                            try {
                                val = (Integer) method.invoke(bean);
                            } catch (InvocationTargetException e) {
                                e.printStackTrace();
                            }
                            value = String.valueOf(val);
                        } else if (className.equalsIgnoreCase("String")) {
                            try {
                                value = (String) method.invoke(bean);
                            } catch (InvocationTargetException e) {
                                e.printStackTrace();
                            }
                        }
                        if (value != null && value != "") {
                            // 添加參數
                            // 將方法名稱轉化為id，去除get，將方法首字母改為小寫
                            String param = method.getName().replaceFirst("get", "");
                            if (param.length() > 0) {
                                String first = String.valueOf(param.charAt(0)).toLowerCase();
                                param = first + param.substring(1);
                            }
                            parameters.put(param, value);
                        }
                    } catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

        return parameters;
    }

    /**
     * 對對Object轉換后, 以key=value&...形式返回按key進行升序排序，以key=value&...形式返回
     * 
     * @param order
     * @return
     */
    public static String sortParam(Map<String, String> order) {
        if (null == order) {
            return null;
        }

        Map<String, String> parameters = new TreeMap<String, String>(new Comparator<String>() {
            public int compare(String obj1, String obj2) {
                return obj1.compareToIgnoreCase(obj2);
            }
        });
        parameters.putAll(order);

        if (null != parameters) {
            StringBuffer sb = new StringBuffer();
            for (Map.Entry<String, String> entry : parameters.entrySet()) {

                if (null != entry.getValue() && !"".equals(entry.getValue()) && !entry.getKey().equals("id_type")
                        && !entry.getKey().equals("id_no") && !entry.getKey().equals("acct_name")
                        && !entry.getKey().equals("flag_modify") && !entry.getKey().equals("user_id")
                        && !entry.getKey().equals("no_agree") && !entry.getKey().equals("card_no")
                        && !entry.getKey().equals("test_mode")) {
                    sb.append(entry.getKey());
                    sb.append(PARAM_EQUAL);
                    sb.append(entry.getValue());
                    sb.append(PARAM_AND);
                }
            }

            String params = sb.toString();
            if (sb.toString().endsWith(PARAM_AND)) {
                params = sb.substring(0, sb.length() - 1);
            }
            log.info("待簽名串:" + params);
            return params;
        }

        return null;
    }
}