package com.ming.util;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
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.SecureRandom;
import java.security.Signature;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
/**
* RSA加密，支持分片加密
* <pre>
* BCD码（Binary-Coded Decimal）亦称二进码十进数或二-十进制代码。
* 用4位二进制数来表示1位十进制数中的0~9这10个数码。
* 是一种二进制的数字编码形式，用二进制编码的十进制代码。
* 注：日常所说的BCD码大都是指8421BCD码形式
* @author Ming
*
*/
public class RSAUtil {
/** 指定加密算法为RSA */
private static String ALGORITHM = "RSA";
/** 指定key的大小 */
private static int KEYSIZE = 1024;
/** 指定公钥存放文件 */
private static String PUBLIC_KEY_FILE = "PublicKey";
/** 指定私钥存放文件 */
private static String PRIVATE_KEY_FILE = "PrivateKey";
public static final String KEY_ALGORITHM = "RSA";
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/**
* 生成密钥对
*/
public static void generateKeyPair() throws Exception {
if (getpublickey() == null || getprivatekey() == null) {
/** RSA算法要求有一个可信任的随机数源 */
SecureRandom sr = new SecureRandom();
/** 为RSA算法创建一个KeyPairGenerator对象 */
KeyPairGenerator kpg = KeyPairGenerator.getInstance(ALGORITHM);
/** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */
kpg.initialize(KEYSIZE, sr);
/** 生成密匙对 */
KeyPair kp = kpg.generateKeyPair();
/** 得到公钥 */
Key publicKey = kp.getPublic();
/** 得到私钥 */
Key privateKey = kp.getPrivate();
/** 用对象流将生成的密钥写入文件 */
ObjectOutputStream oos1 = new ObjectOutputStream(new FileOutputStream(PUBLIC_KEY_FILE));
ObjectOutputStream oos2 = new ObjectOutputStream(new FileOutputStream(PRIVATE_KEY_FILE));
oos1.writeObject(publicKey);
oos2.writeObject(privateKey);
/** 清空缓存，关闭文件输出流 */
oos1.close();
oos2.close();
}
}
/**
* 产生签名
*
* @param data
* @param privateKey
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
// 解密由base64编码的私钥
byte[] keyBytes = decryptBASE64(privateKey);
// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
// 取私钥对象
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(priKey);
signature.update(data);
return encryptBASE64(signature.sign());
}
/**
* 验证签名
*
* @param data
* @param publicKey
* @param sign
* @return
* @throws Exception
*/
public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
// 解密由base64编码的公钥
byte[] keyBytes = decryptBASE64(publicKey);
// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
// 取公钥对象
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(pubKey);
signature.update(data);
// 验证签名是否有效
return signature.verify(decryptBASE64(sign));
}
/**
* BASE64解密
*
* @param key
* @return
* @throws Exception
*/
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}
/**
* BASE64加密
*
* @param key
* @return
* @throws Exception
*/
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}
/**
* 加密方法 source： 源数据
*/
public static String encrypt(String source) throws Exception {
generateKeyPair();
/** 将文件中的公钥对象读出 */
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
Key key = (Key) ois.readObject();
ois.close();
/** 得到Cipher对象来实现对源数据的RSA加密 */
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, key);
int MaxBlockSize = KEYSIZE / 8;
int len = (MaxBlockSize - 11) / 8;
String[] datas = splitString(source, len);
StringBuffer mi = new StringBuffer();
for (String s : datas) {
mi.append(bcd2Str(cipher.doFinal(s.getBytes())));
}
return mi.toString();
}
/**
* 字符串分片
*
* @param string
* 源字符串
* @param len
* 单片的长度（keysize/8）
* @return
*/
public static String[] splitString(String string, int len) {
int x = string.length() / len;
int y = string.length() % len;
int z = 0;
if (y != 0) {
z = 1;
}
String[] strings = new String[x + z];
String str = "";
for (int i = 0; i < x + z; i++) {
if (i == x + z - 1 && y != 0) {
str = string.substring(i * len, i * len + y);
} else {
str = string.substring(i * len, i * len + len);
}
strings[i] = str;
}
return strings;
}
/**
* bcd 转 Str
*
* @param bytes
* @return
*/
public static String bcd2Str(byte[] bytes) {
char temp[] = new char[bytes.length * 2], val;
for (int i = 0; i < bytes.length; i++) {
val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);
temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
val = (char) (bytes[i] & 0x0f);
temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');
}
return new String(temp);
}
/**
* 解密
*
* @param cryptograph
* :密文
* @return 解密后的明文
* @throws Exception
*/
public static String decrypt(String cryptograph) throws Exception {
generateKeyPair();
/** 将文件中的私钥对象读出 */
@SuppressWarnings("resource")
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
Key key = (Key) ois.readObject();
/** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, key);
int key_len = KEYSIZE / 8;
byte[] bytes = cryptograph.getBytes();
byte[] bcd = ASCII2BCD(bytes, bytes.length);
StringBuffer sBuffer = new StringBuffer();
byte[][] arrays = splitArray(bcd, key_len);
for (byte[] arr : arrays) {
sBuffer.append(new String(cipher.doFinal(arr)));
}
return sBuffer.toString();
}
/**
* ASCII 转 BCD
*
* @param ascii
* @param asc_len
* @return
*/
public static byte[] ASCII2BCD(byte[] ascii, int asc_len) {
byte[] bcd = new byte[asc_len / 2];
int j = 0;
for (int i = 0; i < (asc_len + 1) / 2; i++) {
bcd[i] = asc2bcd(ascii[j++]);
bcd[i] = (byte) (((j >= asc_len) ? 0x00 : asc2bcd(ascii[j++])) + (bcd[i] << 4));
}
return bcd;
}
/**
* asc转bcd
*
* @param asc
* @return
*/
public static byte asc2bcd(byte asc) {
byte bcd;
if ((asc >= '0') && (asc <= '9'))
bcd = (byte) (asc - '0');
else if ((asc >= 'A') && (asc <= 'F'))
bcd = (byte) (asc - 'A' + 10);
else if ((asc >= 'a') && (asc <= 'f'))
bcd = (byte) (asc - 'a' + 10);
else
bcd = (byte) (asc - 48);
return bcd;
}
/**
* 字节数组分片
*
* @param data
* @param len
* @return
*/
public static byte[][] splitArray(byte[] data, int len) {
int x = data.length / len;
int y = data.length % len;
int z = 0;
if (y != 0) {
z = 1;
}
byte[][] arrays = new byte[x + z][];
byte[] arr;
for (int i = 0; i < x + z; i++) {
arr = new byte[len];
if (i == x + z - 1 && y != 0) {
System.arraycopy(data, i * len, arr, 0, y);
} else {
System.arraycopy(data, i * len, arr, 0, len);
}
arrays[i] = arr;
}
return arrays;
}
/** 将文件中的公钥对象读出 */
public static String getpublickey() {
try {
@SuppressWarnings("resource")
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));
Key key = (Key) ois.readObject();
String publickey = encryptBASE64(key.getEncoded());
return publickey;
} catch (Exception e) {
LogUtil.exception(e);
}
return null;
}
/** 将文件中的私钥对象读出 */
public static String getprivatekey() {
try {
@SuppressWarnings("resource")
ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));
Key key = (Key) ois.readObject();
String privatekey = encryptBASE64(key.getEncoded());
return privatekey;
} catch (Exception e) {
LogUtil.exception(e);
}
return null;
}
public static void main(String[] args) {
try {
String s = encrypt("allming.com");
System.out.println("加密："+s);
System.out.println("解密："+decrypt(s));
} catch (Exception e) {
e.printStackTrace();
}
}
}
JAVA RSA 加密 解密 工具类 支持分片
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转载自mingzijian.iteye.com/blog/2356357
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