Rsa分段加解密方法

一、首先建一个 Base64Utils 的工具类：

package com.ifp.channel.mobilebank.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import com.sun.org.apache.xml.internal.security.utils.Base64;  
/**
 * <p>
 * BASE64编码解码工具包
 * </p>
 * <p>
 * 依赖javabase64-1.3.1.jar
 * </p>
 * 
 * @author IceWee
 * @date 2012-5-19
 * @version 1.0
 */
public class Base64Utils {
    /**
     * 文件读取缓冲区大小
     */
    private static final int CACHE_SIZE = 1024;
    
    /**
     * <p>
     * BASE64字符串解码为二进制数据
     * </p>
     * 
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
        return Base64.decode(base64.getBytes());
    }
    
    /**
     * <p>
     * 二进制数据编码为BASE64字符串
     * </p>
     * 
     * @param bytes
     * @return
     * @throws Exception
     */
    public static String encode(byte[] bytes) throws Exception {
        return new String(Base64.encode(bytes));
    }
    
    /**
     * <p>
     * 将文件编码为BASE64字符串
     * </p>
     * <p>
     * 大文件慎用，可能会导致内存溢出
     * </p>
     * 
     * @param filePath 文件绝对路径
     * @return
     * @throws Exception
     */
    public static String encodeFile(String filePath) throws Exception {
        byte[] bytes = fileToByte(filePath);
        return encode(bytes);
    }
    
    /**
     * <p>
     * BASE64字符串转回文件
     * </p>
     * 
     * @param filePath 文件绝对路径
     * @param base64 编码字符串
     * @throws Exception
     */
    public static void decodeToFile(String filePath, String base64) throws Exception {
        byte[] bytes = decode(base64);
        byteArrayToFile(bytes, filePath);
    }
    
    /**
     * <p>
     * 文件转换为二进制数组
     * </p>
     * 
     * @param filePath 文件路径
     * @return
     * @throws Exception
     */
    public static byte[] fileToByte(String filePath) throws Exception {
        byte[] data = new byte[0];
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
            data = out.toByteArray();
         }
        return data;
    }
    
    /**
     * <p>
     * 二进制数据写文件
     * </p>
     * 
     * @param bytes 二进制数据
     * @param filePath 文件生成目录
     */
    public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
        InputStream in = new ByteArrayInputStream(bytes);   
        File destFile = new File(filePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = in.read(cache)) != -1) {   
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        in.close();
    }
    
    
}

二、建一个 RSAUtils 工具类：

package com.Rsa;
import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
import com.ifp.channel.mobilebank.util.Base64Utils;
/** */
/**
 * <p>
 * RSA公钥/私钥/签名工具包
 * </p>
 * <p>
 * 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
 * </p>
 * <p>
 * 字符串格式的**在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的**加密，这样保证**的安全也就保证了数据的安全
 * </p>
 * 
 * @author IceWee
 * @date 2012-4-26
 * @version 1.0
 */
public class RSAUtils {
	/**
	 * 加密算法RSA
	 */
	public static final String KEY_ALGORITHM = "RSA";
	/**
	 * 签名算法
	 */
	public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
	/**
	 * 获取公钥的key
	 */
	private static final String PUBLIC_KEY = "RSAPublicKey";
	/**
	 * 获取私钥的key
	 */
	private static final String PRIVATE_KEY = "RSAPrivateKey";
	/**
	 * RSA最大加密明文大小
	 */
	private static final int MAX_ENCRYPT_BLOCK = 117;
	/**
	 * RSA最大解密密文大小
	 */
	private static final int MAX_DECRYPT_BLOCK = 128;
	/**
	 * <p>
	 * 生成**对(公钥和私钥)
	 * </p>
	 *
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> genKeyPair() throws Exception {
		KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
		keyPairGen.initialize(1024);
		KeyPair keyPair = keyPairGen.generateKeyPair();
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
		Map<String, Object> keyMap = new HashMap<String, Object>(2);
		keyMap.put(PUBLIC_KEY, publicKey);//公钥
		keyMap.put(PRIVATE_KEY, privateKey);//私钥
		return keyMap;
	}
	/**
	 * <p>
	 * 用私钥对信息生成数字签名
	 * </p>
	 *
	 * @param data
	 *            已加密数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 *
	 * @return
	 * @throws Exception
	 */
	public static String sign(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = Base64Utils.decode(privateKey);
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initSign(privateK);
		signature.update(data);
		return Base64Utils.encode(signature.sign());
	}
	/** */
	/**
	 * <p>
	 * 校验数字签名
	 * </p>
	 *
	 * @param data
	 *            已加密数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @param sign
	 *            数字签名
	 *
	 * @return
	 * @throws Exception
	 *
	 */
	public static boolean verify(byte[] data, String publicKey, String sign)
			throws Exception {
		byte[] keyBytes = Base64Utils.decode(publicKey);
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		PublicKey publicK = keyFactory.generatePublic(keySpec);
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initVerify(publicK);
		signature.update(data);
		return signature.verify(Base64Utils.decode(sign));
	}
	/** */
	/**
	 * <P>
	 * 私钥解密
	 * </p>
	 *
	 * @param encryptedData
	 *            已加密数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)  
            throws Exception {  
        byte[] keyBytes = Base64Utils.decode(privateKey);  
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);  
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);  
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);  
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.DECRYPT_MODE, privateK);  
        int inputLen = encryptedData.length;  
        ByteArrayOutputStream out = new ByteArrayOutputStream();  
        int offSet = 0;  
        byte[] cache;  
        int i = 0;  
        // 对数据分段解密  
        while (inputLen - offSet > 0) {  
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {  
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);  
            } else {  
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);  
            }  
            out.write(cache, 0, cache.length);  
            i++;  
            offSet = i * MAX_DECRYPT_BLOCK;  
        }  
        byte[] decryptedData = out.toByteArray();  
        out.close();  
        return decryptedData;  
    }  
	/** */
	/**
	 * <p>
	 * 公钥解密
	 * </p>
	 *
	 * @param encryptedData
	 *            已加密数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)  
            throws Exception {  
        byte[] keyBytes = Base64Utils.decode(publicKey);  
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);  
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);  
        Key publicK = keyFactory.generatePublic(x509KeySpec);  
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.DECRYPT_MODE, publicK);  
        int inputLen = encryptedData.length;  
        ByteArrayOutputStream out = new ByteArrayOutputStream();  
        int offSet = 0;  
        byte[] cache;  
        int i = 0;  
        // 对数据分段解密  
        while (inputLen - offSet > 0) {  
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {  
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);  
            } else {  
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);  
            }  
            out.write(cache, 0, cache.length);  
            i++;  
            offSet = i * MAX_DECRYPT_BLOCK;  
        }  
        byte[] decryptedData = out.toByteArray();  
        out.close();  
        return decryptedData;  
    }  
	/** */
	/**
	 * <p>
	 * 公钥加密
	 * </p>
	 *
	 * @param data
	 *            源数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String publicKey)  
            throws Exception {  
        byte[] keyBytes = Base64Utils.decode(publicKey);  
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);  
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);  
        Key publicK = keyFactory.generatePublic(x509KeySpec);  
        // 对数据加密  
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());  
        cipher.init(Cipher.ENCRYPT_MODE, publicK);  
        int inputLen = data.length;  
        ByteArrayOutputStream out = new ByteArrayOutputStream();  
        int offSet = 0;  
        byte[] cache;  
        int i = 0;  
        // 对数据分段加密  
        while (inputLen - offSet > 0) {  
            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {  
                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);  
            } else {  
                cache = cipher.doFinal(data, offSet, inputLen - offSet);  
            }  
            out.write(cache, 0, cache.length);  
            i++;  
            offSet = i * MAX_ENCRYPT_BLOCK;  
        }  
        byte[] encryptedData = out.toByteArray();  
        out.close();  
        return encryptedData;  
    }  
	/** */
	/**
	 * <p>
	 * 私钥加密
	 * </p>
	 *
	 * @param data
	 *            源数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	 public static byte[] encryptByPrivateKey(byte[] data, String privateKey)  
	            throws Exception {  
	        byte[] keyBytes = Base64Utils.decode(privateKey);  
	        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);  
	        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);  
	        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);  
	        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());  
	        cipher.init(Cipher.ENCRYPT_MODE, privateK);  
	        int inputLen = data.length;  
	        ByteArrayOutputStream out = new ByteArrayOutputStream();  
	        int offSet = 0;  
	        byte[] cache;  
	        int i = 0;  
	        // 对数据分段加密  
	        while (inputLen - offSet > 0) {  
	            if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {  
	                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);  
	            } else {  
	                cache = cipher.doFinal(data, offSet, inputLen - offSet);  
	            }  
	            out.write(cache, 0, cache.length);  
	            i++;  
	            offSet = i * MAX_ENCRYPT_BLOCK;  
	        }  
	        byte[] encryptedData = out.toByteArray();  
	        out.close();  
	        return encryptedData;  
	    }  
	/** */
	/**
	 * <p>
	 * 获取私钥
	 * </p>
	 *
	 * @param keyMap
	 *            **对
	 * @return
	 * @throws Exception
	 */
	public static String getPrivateKey(Map<String, Object> keyMap)
			throws Exception {
		Key key = (Key) keyMap.get(PRIVATE_KEY);
		return Base64Utils.encode(key.getEncoded());
	}
	/** */
	/**
	 * <p>
	 * 获取公钥
	 * </p>
	 *
	 * @param keyMap
	 *            **对
	 * @return
	 * @throws Exception
	 */
	public static String getPublicKey(Map<String, Object> keyMap)
			throws Exception {
		Key key = (Key) keyMap.get(PUBLIC_KEY);
		return Base64Utils.encode(key.getEncoded());
	}
}

三、编写一个测试类：  此代码引用类做了裁剪，可以自己创建一个类把下面类中的方法进行摘出使用，有问题可以给我留言看到会给你回复！

 package com.Rsa;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
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 java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class RsaEncryptionInterceptor{
	
	/*
	public void preHandle(IContext context) throws BaseException {
		System.out.println("RsaEncryptionInterceptor==========>进入Rsa解密前置拦截器");
		System.out.println("RsaEncryptionInterceptor==========>开始调用Rsa解密服务");
		try {
			System.out.println("接收到的所有参数：======== \n" + context);
			ClogicContext clContext = (ClogicContext) context;
			
			//接收传过来的参数，强转成字符串
			String parm = (String) clContext.getValue("RsaCode");
			if(parm != null && !parm.isEmpty()){
				System.out.println("RsaEncryptionInterceptor========>接收到的参数");
				System.out.println(parm);
				
				//去执行下面的解密逻辑，并返回解密后的参数
				String rsaOpen = RsaOpen(parm);
				
				System.out.println("RsaEncryptionInterceptor========解密之后的参数");
				System.out.println(rsaOpen);
				
				clContext.setValue("RsaCode", rsaOpen);
			}
			
		} catch (Exception e) {
			Trace.log(Trace.MODULE_INTERCEPTOR, Trace.LEVEL_ERROR, "错误:",e);
			e.printStackTrace();
		}
	}*/
	public static void main(String[] args) {
		String str = "{body:{custNo:00000000000000283413,isflag:0,ceMIICdwIBADANBgkqhk"
				+ "iG9w0BAQEFAASCAmEwggJdAgEAAoGBALO/ePNWqCHKNSw/sH4UGvTVPmbn"
		+"+TSkTyD/z+U6e8Nz533qcwwW9quo2MQcNioU1kHbRsPBFShTQfMbXFXiWHdzI/X4uDZHrLexn2oo"
		+"maf4qQDSUTVE+1QPqFR503LXcyMBVac9SEH18bA2zFfEj/oStIe3aiZX5lUyXCGtxz7hAgMBAAEC"
		+"gYEApKQkaFeep1ys+bvYsJM/4bSVdPLUG/jIlgRa6692/59hkb825AMArFl7O55PqpntauMr3VA1"
		+"Tft88+3C1NP/jNc9H+ldvXYP5grObcs5/r+rHgQysihJh//P+vRUnHMacGnjUOIjVS+dE5l35bKb"
		+"FzMVmzvAy6DU7XXi/nWjNUUCQQDsGiv+880bP0Oq6vEtUfTO99usmEcB1/yxp8TJq62oJEIa0Dx3"
		+"9K+R8MFwcb+GWW1FNKyaUNEX1CuofnXa1/PrAkEAwuV5p2tPqMTk7bmkmw3uflUJBVwJnZIBrmg7"
		+"+YcxnIgIRDk=";
		try {
			RsaOpen(str);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	
	public static String RsaOpen(String urlPath) throws Exception {
		Map<String, Object> keyMap = RSAUtils.genKeyPair();
		String publicKey = RSAUtils.getPublicKey(keyMap);
		String privateKey = RSAUtils.getPrivateKey(keyMap);
		System.err.println("公钥: \n\r" + publicKey);
		System.err.println("私钥： \n\r" + privateKey);
		System.err.println("公钥加密——私钥解密");
		String source = urlPath;
		System.out.println("\r加密前文字：\r\n" + source);
		byte[] data = source.getBytes();
		byte[] encodedData = RSAUtils.encryptByPublicKey(data, publicKey);
		System.out.println("加密后文字：\r\n" + new String(encodedData));
		byte[] decodedData = RSAUtils.decryptByPrivateKey(encodedData,
				privateKey);
		String target = new String(decodedData);
		System.out.println("解密后文字: \r\n" + target);
		
		return target;
	}
}