RSA验证

工具类：

import java.io.File;
import java.io.IOException;
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.LinkedList;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.codec.binary.Base64;



/** 
 * 经典的数字签名算法RSA 
 * 数字签名 
 * @author xpwang 
 * */  
public class RSAUtil {  
    //数字签名，密钥算法  
    public static final String KEY_ALGORITHM="RSA";  
    /** 
     * 数字签名 
     * 签名/验证算法 
     * */  
    public static final String SIGNATURE_ALGORITHM="MD5withRSA";  

    /** 
     * 签名 
     * @param data待签名数据 
     * @param privateKey 密钥 
     * @return byte[] 数字签名 
     * */  
    public static byte[] sign(byte[] data,byte[] privateKey) throws Exception{  

        //取得私钥  
        PKCS8EncodedKeySpec pkcs8KeySpec=new PKCS8EncodedKeySpec(privateKey);  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //生成私钥  
        PrivateKey priKey=keyFactory.generatePrivate(pkcs8KeySpec);  
        //实例化Signature  
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);  
        //初始化Signature  
        signature.initSign(priKey);  
        //更新  
        signature.update(data);  
        return signature.sign();  
    }  
    /** 
     * 校验数字签名 
     * @param data 待校验数据 
     * @param publicKey 公钥 
     * @param sign 数字签名 
     * @return boolean 校验成功返回true，失败返回false 
     * */  
    public static boolean verify(byte[] data,byte[] publicKey,byte[] sign) throws Exception{  
        //转换公钥材料  
        //实例化密钥工厂  
        KeyFactory keyFactory=KeyFactory.getInstance(KEY_ALGORITHM);  
        //初始化公钥  
        //密钥材料转换  
        X509EncodedKeySpec x509KeySpec=new X509EncodedKeySpec(publicKey);  
        //产生公钥  
        PublicKey pubKey=keyFactory.generatePublic(x509KeySpec);  
        //实例化Signature  
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);  
        //初始化Signature  
        signature.initVerify(pubKey);  
        //更新  
        signature.update(data);  
        //验证  
        return signature.verify(sign);  
    }  
    public static boolean verify(String data,String publicKey,String sign) throws Exception{  

        return verify(data.getBytes(),publicKey.getBytes(),sign.getBytes()); 
    }  

}  

秘钥生成：

/** 
 * 经典的数字签名算法RSA 
 * 数字签名 
 * @author xpwang 
 * */  
public class RSAUtil {  
    //数字签名，密钥算法  
    public static final String KEY_ALGORITHM="RSA";  

    public static final String SIGNATURE_ALGORITHM="MD5withRSA";  
   // RSA密钥长度，RSA算法的默认密钥长度是1024 密钥长度必须是64的倍数，在512到65536位之间 
    private static final int KEY_SIZE=512;  
    //公钥  
    private static final String PUBLIC_KEY="RSAPublicKey";  
    //私钥  
    private static final String PRIVATE_KEY="RSAPrivateKey";  


   /** 
     * 初始化密钥对 
     * @return Map 甲方密钥的Map 
     * */
    public static Map<String,Object> initKey() throws Exception{  
        //实例化密钥生成器  
        KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance(KEY_ALGORITHM);  
        //初始化密钥生成器  
        keyPairGenerator.initialize(KEY_SIZE);  
        //生成密钥对  
        KeyPair keyPair=keyPairGenerator.generateKeyPair();  
        //甲方公钥  
        RSAPublicKey publicKey=(RSAPublicKey) keyPair.getPublic();  
        //甲方私钥  
        RSAPrivateKey privateKey=(RSAPrivateKey) keyPair.getPrivate();  
        //将密钥存储在map中  
        Map<String,Object> keyMap=new HashMap<String,Object>();  
        keyMap.put(PUBLIC_KEY, publicKey);  
        keyMap.put(PRIVATE_KEY, privateKey);  
        return keyMap;  

    }  


    public static byte[] getPrivateKey(Map<String, Object> keyMap) {
         Key key=(Key) keyMap.get(PRIVATE_KEY);  
            return key.getEncoded();  
    }
    public static byte[] getPublicKey(Map<String, Object> keyMap) {
         Key key=(Key) keyMap.get(PUBLIC_KEY);  
            return key.getEncoded();  
    }  
}