com.qxml.tools.encrypt.RSAUtils Maven / Gradle / Ivy
package com.qxml.tools.encrypt;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.BigInteger;
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.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.List;
import javax.crypto.Cipher;
/**
* @author Mr.Zheng
* @date 2014年8月22日 下午1:44:23
*/
public final class RSAUtils {
private static String RSA = "RSA";
private static final int MAX_ENCRYPT_BLOCK_1024 = 117;
private static final int MAX_DECRYPT_BLOCK_1024 = 128;
private static final int MAX_ENCRYPT_BLOCK_2048 = 245;
private static final int MAX_DECRYPT_BLOCK_2048 = 256;
private static final int CUR_ENCRYPT_BLOCK = MAX_ENCRYPT_BLOCK_1024;
private static final int CUR_DECRYPT_BLOCK = MAX_DECRYPT_BLOCK_1024;
private static int KEYBIT = 2048;// 密钥位数
/**
* 随机生成RSA密钥对(默认密钥长度为1024)
*
* @return
*/
public static KeyPair generateRSAKeyPair()
{
return generateRSAKeyPair(KEYBIT);
}
/**
* 随机生成RSA密钥对
*
* @param keyLength
* 密钥长度，范围：512～2048
* 一般1024
* @return
*/
public static KeyPair generateRSAKeyPair(int keyLength)
{
try
{
KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA);
kpg.initialize(keyLength);
return kpg.genKeyPair();
} catch (NoSuchAlgorithmException e)
{
e.printStackTrace();
return null;
}
}
/**
* 用公钥加密
* 每次加密的字节数，不能超过密钥的长度值减去11
*
* @param data
* 需加密数据的byte数据
* 公钥
* @return 加密后的byte型数据
*/
public static byte[] encryptData(byte[] data, PublicKey publicKey)
{
try
{
Cipher cipher = Cipher.getInstance(RSA);
// 编码前设定编码方式及密钥
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
// 传入编码数据并返回编码结果
return cipher.doFinal(data);
} catch (Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* 用私钥解密
*
* @param encryptedData
* 经过encryptedData()加密返回的byte数据
* @param privateKey
* 私钥
* @return
*/
public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey)
{
try
{
Cipher cipher = Cipher.getInstance(RSA);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return cipher.doFinal(encryptedData);
} catch (Exception e)
{
return null;
}
}
/**
* 用私钥加密
* 每次加密的字节数，不能超过密钥的长度值减去11
*
* @param data
* 需加密数据的byte数据
* 私钥
* @return 加密后的byte型数据
*/
public static byte[] encryptDataByPrivateKey(byte[] data, PrivateKey privateKey)
{
try
{
Cipher cipher = Cipher.getInstance(RSA);
// 编码前设定编码方式及密钥
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
// 传入编码数据并返回编码结果
return cipher.doFinal(data);
} catch (Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* 用公钥解密
*
* @param encryptedData
* 经过encryptedData()加密返回的byte数据
* @param publicKey
* 公钥
* @return
*/
public static byte[] decryptDataByPublicKey(byte[] encryptedData, PublicKey publicKey)
{
try
{
System.out.println("f decryptDataByPublicKey "+encryptedData.length);
Cipher cipher = Cipher.getInstance(RSA);
cipher.init(Cipher.DECRYPT_MODE, publicKey);
return cipher.doFinal(encryptedData);
} catch (Exception e)
{
e.printStackTrace();
return null;
}
}
/**
* 通过公钥byte[](publicKey.getEncoded())将公钥还原，适用于RSA算法
*
* @param keyBytes
* @return
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException,
InvalidKeySpecException
{
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PublicKey publicKey = keyFactory.generatePublic(keySpec);
return publicKey;
}
/**
* 通过私钥byte[]将公钥还原，适用于RSA算法
*
* @param keyBytes
* @return
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException,
InvalidKeySpecException
{
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
/**
* 使用N、e值还原公钥
*
* @param modulus
* @param publicExponent
* @return
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
public static PublicKey getPublicKey(String modulus, String publicExponent)
throws NoSuchAlgorithmException, InvalidKeySpecException
{
BigInteger bigIntModulus = new BigInteger(modulus);
BigInteger bigIntPrivateExponent = new BigInteger(publicExponent);
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PublicKey publicKey = keyFactory.generatePublic(keySpec);
return publicKey;
}
/**
* 使用N、d值还原私钥
*
* @param modulus
* @param privateExponent
* @return
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
public static PrivateKey getPrivateKey(String modulus, String privateExponent)
throws NoSuchAlgorithmException, InvalidKeySpecException
{
BigInteger bigIntModulus = new BigInteger(modulus);
BigInteger bigIntPrivateExponent = new BigInteger(privateExponent);
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent);
KeyFactory keyFactory = KeyFactory.getInstance(RSA);
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
/**
* 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 PublicKey loadPublicKey(String publicKeyStr) throws Exception
{
try
{
byte[] buffer = Base64Utils.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");
}
}
/**
* 从字符串中加载私钥
* 加载时使用的是PKCS8EncodedKeySpec（PKCS#8编码的Key指令）。
*
* @param privateKeyStr
* @return
* @throws Exception
*/
public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception
{
try
{
byte[] buffer = Base64Utils.decode(privateKeyStr);
// X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);
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");
}
}
/**
* 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 PublicKey loadPublicKey(InputStream in) throws Exception
{
try
{
return loadPublicKey(readKey(in));
} 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");
}
}
/**
* 从文件中加载私钥
*
* 私钥文件名
* @return 是否成功
* @throws Exception
*/
public static PrivateKey loadPrivateKey(InputStream in) throws Exception
{
try
{
return loadPrivateKey(readKey(in));
} 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");
}
}
/**
* 读取密钥信息
*
* @param in
* @return
* @throws IOException
*/
private static String readKey(InputStream in) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String readLine = null;
StringBuilder sb = new StringBuilder();
while ((readLine = br.readLine()) != null)
{
if (readLine.charAt(0) == '-')
{
continue;
} else
{
sb.append(readLine);
sb.append('\r');
}
}
return sb.toString();
}
/**
* 使用私钥将数据进行分段加密
*
* @param dataStr 要加密的数据
* @param privateKeyStr 私钥 Base64 字符串，X509 格式
* @return 加密后的 Base64 编码数据，加密失败返回 null
*/
public static String encryptByPrivateKey(String dataStr, String privateKeyStr) {
ByteArrayOutputStream bops = new ByteArrayOutputStream();
try {
Cipher cipher = Cipher.getInstance("RSA");
PrivateKey privateKey = loadPrivateKey(privateKeyStr);
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] bytes = dataStr.getBytes();
int inputLen = bytes.length;
int offLen = 0;//偏移量
int i = 0;
while(inputLen - offLen > 0){
byte [] cache;
if(inputLen - offLen > CUR_ENCRYPT_BLOCK){
cache = cipher.doFinal(bytes, offLen, CUR_ENCRYPT_BLOCK);
}else{
cache = cipher.doFinal(bytes, offLen,inputLen - offLen);
}
bops.write(cache);
i++;
offLen = CUR_ENCRYPT_BLOCK * i;
}
byte[] encryptedData = bops.toByteArray();
return Base64Utils.encode(encryptedData);
} catch (Exception e) {
e.printStackTrace();
return null;
} finally {
try {
bops.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 使用公钥将加密后的 Base64 字符串进行分段解密
*
* @param dataStr 加密后的 Base64 字符串
* @param publicKeyStr 公钥 Base64 字符串，PKCS8 格式
* @return 解密后的明文，解密失败返回 null
*/
public static String decryptByPublicKey(String dataStr, String publicKeyStr) {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
try {
Cipher cipher = Cipher.getInstance("RSA");
PublicKey publicKey = loadPublicKey(publicKeyStr);
cipher.init(Cipher.DECRYPT_MODE, publicKey);
byte[] bytes = Base64Utils.decode(dataStr);
int inputLen = bytes.length;
int offLen = 0;
int i = 0;
while(inputLen - offLen > 0){
byte[] cache;
if(inputLen - offLen > CUR_DECRYPT_BLOCK){
cache = cipher.doFinal(bytes,offLen,CUR_DECRYPT_BLOCK);
}else{
cache = cipher.doFinal(bytes,offLen,inputLen - offLen);
}
byteArrayOutputStream.write(cache);
i++;
offLen = CUR_DECRYPT_BLOCK * i;
}
byteArrayOutputStream.close();
byte[] byteArray = byteArrayOutputStream.toByteArray();
return new String(byteArray);
} catch (Exception e) {
e.printStackTrace();
return null;
} finally {
try {
byteArrayOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
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