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！

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;import com.fcplay.Base64;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 blocke.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RSAcipher = 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RSAcipher = 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RSAcipher = 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RSAcipher = 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 groupsif (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 spacesint 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 nullb1 = 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 charactersif (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 3cQlb3 = 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 whitespaceint 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="G:/tmp/";//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();}
}

 

看看运行截图：