1:RsaUtil.JAVA
import org.Apache.commons.codec.binary.Base64;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.security.*;
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.HashMap;
import java.util.Map;
public class RsaUtil {
public static final String KEY_ALGORITHM = "RSA";
//public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
private static final String PUBLIC_KEY = "FrankPublic";
private static final String PRIVATE_KEY = "FrankPrivateKey";
/**
* 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;
//获得公钥
public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
//获得map中的公钥对象 转为key对象
Key key = (Key) keyMap.get(PUBLIC_KEY);
//byte[] publicKey = key.getEncoded();
//编码返回字符串
return encryptBASE64(key.getEncoded());
}
//获得私钥
public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
//获得map中的私钥对象 转为key对象
Key key = (Key) keyMap.get(PRIVATE_KEY);
//byte[] privateKey = key.getEncoded();
//编码返回字符串
return encryptBASE64(key.getEncoded());
}
//解码返回byte
public static byte[] decryptBASE64(String key) throws Exception {
return (new BASE64Decoder()).decodeBuffer(key);
}
//编码返回字符串
public static String encryptBASE64(byte[] key) throws Exception {
return (new BASE64Encoder()).encodeBuffer(key);
}
//map对象中存放公私钥
public static Map<String, Object> initKey() throws Exception {
//获得对象 KeyPAIrGenerator 参数 RSA 1024个字节
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
//通过对象 KeyPairGenerator 获取对象KeyPair
KeyPair keyPair = keyPairGen.generateKeyPair();
//通过对象 KeyPair 获取RSA公私钥对象RSAPublicKey RSAPrivateKey
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
//公私钥对象存入map中
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
* 获取私钥
*
* @param privateKey 私钥字符串
* @return
*/
public static PrivateKey getPrivateKey() throws Exception {
String privateKey="XXX";
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
byte[] decodedKey = Base64.decodeBase64(privateKey.getBytes());
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decodedKey);
return keyFactory.generatePrivate(keySpec);
}
/**
* 获取公钥
*
* @param publicKey 公钥字符串
* @return
*/
public static PublicKey getPublicKey() throws Exception {
String publicKey="XXX";
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
byte[] decodedKey = Base64.decodeBase64(publicKey.getBytes());
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(decodedKey);
return keyFactory.generatePublic(keySpec);
}
/**
* RSA加密
*
* @param data 待加密数据
* @return
*/
public static String encrypt(String data) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, getPublicKey());
int inputLen = data.getBytes().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.getBytes(), offset, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data.getBytes(), offset, inputLen - offset);
}
out.write(cache, 0, cache.length);
i++;
offset = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
// 获取加密内容使用base64进行编码,并以UTF-8为标准转化成字符串
// 加密后的字符串
return new String(Base64.encodeBase64String(encryptedData));
}
/**
* RSA解密
*
* @param data 待解密数据
* @return
*/
public static String decrypt(String data) throws Exception {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, getPrivateKey());
byte[] dataBytes = Base64.decodeBase64(data);
int inputLen = dataBytes.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(dataBytes, offset, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(dataBytes, offset, inputLen - offset);
}
out.write(cache, 0, cache.length);
i++;
offset = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
// 解密后的内容
return new String(decryptedData, "UTF-8");
}
}
2:调用方式
先调用 initKey() 方法 获取到一个Map对象,里面包含了公钥和私钥,key值就是上面定义的 PUBLIC_KEY 和 PRIVATE_KEY 两个常量
如果想看里面具体的 公钥和私钥字符串形式 将此Map对象做为参数,
传递到 getPublicKey(Map<String, Object> keyMap) 和 getPrivateKey(Map<String, Object> keyMap) 方法中即可获取到值
好了,看完以后,将需要加密的字符放到 encrypt(String data) 方法中进行加密,将需要解密的字符放到 decrypt(String data) 方法中进行解密
即可。