RSA 签名、验证、加密、解密帮助类

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.PrivateKey;

import java.security.PublicKey;

import java.security.Signature;

import java.security.SignatureException;

import java.security.spec.EncodedKeySpec;

import java.security.spec.InvalidKeySpecException;

import java.security.spec.PKCS8EncodedKeySpec;

import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;

/**

* RSA 签名、验证、加密、解密帮助类

*

* @author sam

*

*/

public class RsaHelper

{

// 签名对象

private Signature sign;

private static final RsaHelper rsaHelper = new RsaHelper();

private String pubkey;

private String prikey;

private RsaHelper()

{

try

{

sign = Signature.getInstance("SHA1withRSA");

}

catch (NoSuchAlgorithmException nsa)

{

System.out.println("" + nsa.getMessage());

}

}

public static RsaHelper getInstance()

{

return rsaHelper;

}

private PrivateKey getPrivateKey(String privateKeyStr)

{

try

{

byte[] privateKeyBytes = b64decode(privateKeyStr);

KeyFactory keyFactory = KeyFactory.getInstance("RSA");

EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyBytes);

return keyFactory.generatePrivate(privateKeySpec);

}

catch (InvalidKeySpecException e)

{

System.out.println("Invalid Key Specs. Not valid Key files." + e.getCause());

return null;

}

catch (NoSuchAlgorithmException e)

{

System.out.println("There is no such algorithm. Please check the JDK ver." + e.getCause());

return null;

}

}

private PublicKey getPublicKey(String publicKeyStr)

{

try

{

byte[] publicKeyBytes = b64decode(publicKeyStr);

KeyFactory keyFactory = KeyFactory.getInstance("RSA");

EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(publicKeyBytes);

return keyFactory.generatePublic(publicKeySpec);

}

catch (InvalidKeySpecException e)

{

System.out.println("Invalid Key Specs. Not valid Key files." + e.getCause());

return null;

}

catch (NoSuchAlgorithmException e)

{

System.out.println("There is no such algorithm. Please check the JDK ver." + e.getCause());

return null;

}

}

/**

* RSA 数据签名

*

* @param toBeSigned

*            (待签名的原文)

* @param priKey

*            (RSA私钥）

* @return （返回RSA签名后的数据签名数据base64编码）

*/

public String signData(String toBeSigned, String priKey)

{

try

{

PrivateKey privateKey = getPrivateKey(priKey);

byte[] signByte = toBeSigned.getBytes("utf-8");

Signature rsa = Signature.getInstance("SHA1withRSA");

rsa.initSign(privateKey);

rsa.update(signByte);

return b64encode(rsa.sign());

}

catch (NoSuchAlgorithmException ex)

{

System.out.println(ex);

}

catch (InvalidKeyException in)

{

System.out.println("Invalid Key file.Please check the key file path" + in.getCause());

}

catch (Exception se)

{

System.out.println(se);

}

return null;

}

/**

* RSA 数据签名验证

*

* @param signature

*            （RSA签名数据（base64编码）

* @param data

*            （待验证的数据原文）

* @param pubKey

*            （RSA公钥数据）

* @return 返回验证结果（TRUE:验证成功；FALSE:验证失败）

*/

public boolean verifySignature(String signature, String data, String pubKey)

{

try

{

byte[] signByte = b64decode(signature);

byte[] dataByte = data.getBytes("utf-8");

PublicKey publicKey = getPublicKey(pubKey);

sign.initVerify(publicKey);

sign.update(dataByte);

return sign.verify(signByte);

}

catch (SignatureException e)

{

e.printStackTrace();

}

catch (Exception e)

{

e.printStackTrace();

}

return false;

}

/**

* base64编码

*

* @param data

* @return

*/

private String b64encode(byte[] data)

{

return new BASE64Encoder().encode(data);

}

/**

* base64解码

*

* @param data

* @return

*/

private byte[] b64decode(String data)

{

try

{

return new BASE64Decoder().decodeBuffer(data);

}

catch (Exception ex)

{

}

return null;

}

/**

* RSA数据加密

*

* @param data

*            （需要加密的数据）

* @param pubKey

*            （RSA公钥）

* @return 返回加密后的密文（BASE64编码）

*/

public String encryptData(String data, String pubKey)

{

try

{

byte[] dataByte = data.getBytes("utf-8");

PublicKey publicKey = getPublicKey(pubKey);

Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

cipher.init(Cipher.ENCRYPT_MODE, publicKey);

return b64encode(cipher.doFinal(dataByte));

}

catch (Exception e)

{

return null;

}

}

/**

* RSA数据解密

*

* @param encryptedData

*            （需要解密的数据base64编码数据）

* @param priKey

*            （RSA的私钥）

* @return 返回解密后的原始明文

*/

public String decryptData(String encryptedData, String priKey)

{

try

{

byte[] encryData = b64decode(encryptedData);

PrivateKey privateKey = getPrivateKey(priKey);

Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

cipher.init(Cipher.DECRYPT_MODE, privateKey);

return new String(cipher.doFinal(encryData), "utf-8");

}

catch (Exception e)

{

return null;

}

}

/**

* 得到私钥字符串（经过base64编码）

*

* @return

*/

public static String getPriKeyString(PrivateKey key) throws Exception

{

byte[] keyBytes = key.getEncoded();

String s = (new BASE64Encoder()).encode(keyBytes);

return s;

}

/**

* 得到公钥字符串（经过base64编码）

*

* @return

*/

public static String getPubKeyString(PublicKey key) throws Exception

{

byte[] keyBytes = key.getEncoded();

String s = (new BASE64Encoder()).encode(keyBytes);

return s;

}

/**

* 生成密钥 自动产生RSA1024位密钥

*

* @throws NoSuchAlgorithmException

* @throws IOException

*/

public void getAutoCreateRSA() throws NoSuchAlgorithmException, IOException

{

try

{

KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");

kpg.initialize(1024);

KeyPair kp = kpg.genKeyPair();

PublicKey puk = kp.getPublic();

PrivateKey prk = kp.getPrivate();

pubkey = getPubKeyString(puk);

prikey = getPriKeyString(prk);

System.out.print("pubkey==:"+pubkey.replaceAll("\r", "").replaceAll("\n", ""));

System.out.print("prikey==:"+prikey.replaceAll("\r", "").replaceAll("\n", ""));

}

catch (Exception e)

{

e.printStackTrace();

}

}

public String getPubkey()

{

return pubkey;

}

public void setPubkey(String pubkey)

{

this.pubkey = pubkey;

}

public String getPrikey()

{

return prikey;

}

public void setPrikey(String prikey)

{

this.prikey = prikey;

}

}