转载自 https://www.cnblogs.com/waliwaliwa/p/7503000.html
什么是RSA加密算法
RSA是一种典型的非对称性加密算法，具体介绍可参考阮一峰的日志 RSA算法原理
下面是使用RSA算法对传输内容进行加密的一个简要Java案例，主要用到了三个类，大体实现如下：
对内容进行RSA加密和解密校验的类
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec; 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 * @return 布尔值 */ 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; } } Base64基础类
public 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; } } 在过滤器的Request中对加签的请求进行验签，在Response中对返回的参数加签。
import java.nio.charset.Charset;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Value; import com.alibaba.fastjson.JSONObject; public class ChannelSignature implements ServletChannelInterceptor{ private final static Logger logger = (Logger) LoggerFactory.getLogger(ChannelSignature.class); private static final String DEFAULT_CHARSET = "UTF-8"; /是否签名验签，true:验签 ,false:不进行验签/ private boolean verifySignFlag; /私钥路径/ @Value("${privateKey}") private String privateKey; /公钥路径/ @Value("${publicKey}") private String publicKey; @Override public void onRequest(ChannelContext<HttpServletRequest, HttpServletResponse> channelContext, ContextEx contextEx) throws FcsiException{ if(!verifySignFlag){logger.debug("don't need verif");return;} Object object = channelContext.getRequestPayload(); String json = new String((byte[])object,Charset.forName(DEFAULT_CHARSET)); JSONObject jsonObject = JSONObject.parseObject(json); String requestParamStr = jsonObject.getString("requestData"); String vSign = jsonObject.getString("sign"); logger.debug("verif sign begin ... ... requestParamStr:{} signStr:{}",requestParamStr,vSign); Boolean verifResult = RSASignature.doCheck(requestParamStr, vSign, publicKey); if(!verifResult){throw new SignatureException(MsgConstants.IFP_230002,"验签异常");} logger.debug("verif sign end ... ... signResult:{}",verifResult); } @Override public void onResponse(ChannelContext<HttpServletRequest, HttpServletResponse> channelContext, ContextEx contextEx, Throwable ex) { JSONObject jsonObject = null; if(ex instanceof SignatureException ){jsonObject = getSignatureExceptionRespData(ex); sign(channelContext,jsonObject);return;} Object object = channelContext.getResponsePalyload(); if(null == object){logger.debug("responsePalyload is null");return;} String json = new String((byte[])object,Charset.forName("UTF8")); jsonObject = JSONObject.parseObject(json); sign(channelContext,jsonObject); } /** * 对响应数据进行签名，并将响应结果放至ResponsePayload * @param channelContext * @param jsonObject */ private void sign(ChannelContext<HttpServletRequest, HttpServletResponse> channelContext, JSONObject jsonObject) { String responseParamStr = jsonObject.getString("responseData"); logger.debug("generate sign begin ... ... signParamStr:{}",responseParamStr); String sign=RSASignature.sign(responseParamStr,privateKey); //对原始报文进行签名 logger.debug("generate sign end ... ... signStr:{}",sign); jsonObject.put("sign", sign); String str = jsonObject.toString(); channelContext.setResponsePayload((Object)str.getBytes(Charset.forName(DEFAULT_CHARSET))); } /** * 组装签名异常响应数据 * @param ex * @return */ private JSONObject getSignatureExceptionRespData(Throwable ex) { String code = ((SignatureException) ex).getCode(); String defaultMessage = ((SignatureException) ex).getMessage(); String[] errMessageStr= defaultMessage.split("]"); String msg = errMessageStr[1]; JSONObject jsonObject = new JSONObject();jsonObject.put("code", code); jsonObject.put("msg", msg); JSONObject respJsonObject = new JSONObject(); respJsonObject.put("responseData", jsonObject); return respJsonObject; } public boolean isVerifySignFlag() { return verifySignFlag; } public void setVerifySignFlag(boolean verifySignFlag) { this.verifySignFlag = verifySignFlag; } }