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Posted on 2012-05-19 16:54 IceWee 閱讀(42694) 評論(7) 編輯 收藏 所屬分類: Java 、 加解密
該工具類中用到了BASE64，需要借助第三方類庫：javabase64-1.3.1. jar
注意：
RSA加密明文最大長度117字節，解密要求密文最大長度為128字節，所以在加密和解密的過程中需要分塊進行。
RSA加密對明文的長度是有限制的，如果加密數據過大會拋出如下異常：  Exception in thread "main" javax.crypto.IllegalBlockSizeException: Data must not be longer than 117 bytes
at com.sun.crypto.provider.RSACipher.a(DashoA13*..)
at com.sun.crypto.provider.RSACipher.engineDoFinal(DashoA13*..)
at javax.crypto.Cipher.doFinal(DashoA13*..)RSAUtils.java package security;
import java.io.ByteArrayOutputStream;
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.Map;
import javax.crypto.Cipher;
  /** *//**
 * <p>
* RSA公鑰/私鑰/簽名工具包
* </p>
* <p>
* 羅納德·李維斯特（Ron [R]ivest）、阿迪·薩莫爾（Adi [S]hamir）和倫納德·阿德曼（Leonard [A]dleman）
* </p>
* <p>
* 字符串格式的密鑰在未在特殊說明情況下都為BASE64編碼格式<br/>
* 由于非對稱加密速度極其緩慢，一般文件不使用它來加密而是使用對稱加密，<br/>
* 非對稱加密算法可以用來對對稱加密的密鑰加密，這樣保證密鑰的安全也就保證了數據的安全
* </p>
*
* @author IceWee
* @date 2012-4-26
* @version 1.0
 */
public class RSAUtils  {
  /** *//**
* 加密算法RSA
 */
public static final String KEY_ALGORITHM = "RSA";
/** *//**
* 簽名算法
*/
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/** *//**
* 獲取公鑰的key
*/
private static final String PUBLIC_KEY = "RSAPublicKey";
/** *//**
* 獲取私鑰的key
*/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/** *//**
* 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;
/** *//**
* <p>
* 生成密鑰對(公鑰和私鑰)
* </p>
*
* @return
* @throws Exception
*/
public static Map<String, Object> genKeyPair() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/** *//**
* <p>
* 用私鑰對信息生成數字簽名
* </p>
*
* @param data 已加密數據
* @param privateKey 私鑰(BASE64編碼)
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return Base64Utils.encode(signature.sign());
}
/** *//**
* <p>
* 校驗數字簽名
* </p>
*
* @param data 已加密數據
* @param publicKey 公鑰(BASE64編碼)
* @param sign 數字簽名
*
* @return
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64Utils.decode(sign));
}
/** *//**
* <P>
* 私鑰解密
* </p>
*
* @param encryptedData 已加密數據
* @param privateKey 私鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公鑰解密
* </p>
*
* @param encryptedData 已加密數據
* @param publicKey 公鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公鑰加密
* </p>
*
* @param data 源數據
* @param publicKey 公鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 對數據加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 私鑰加密
* </p>
*
* @param data 源數據
* @param privateKey 私鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 獲取私鑰
* </p>
*
* @param keyMap 密鑰對
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64Utils.encode(key.getEncoded());
}
/** *//**
* <p>
* 獲取公鑰
* </p>
*
* @param keyMap 密鑰對
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64Utils.encode(key.getEncoded());
}
}
Base64Utils.java  package security;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import it.sauronsoftware.base64.Base64;
  /** *//**
 * <p>
* BASE64編碼解碼工具包
* </p>
* <p>
* 依賴javabase64-1.3.1.jar
* </p>
*
* @author IceWee
* @date 2012-5-19
* @version 1.0
 */
public class Base64Utils {
  /** *//**
* 文件讀取緩沖區大小
 */
private static final int CACHE_SIZE = 1024;
/** *//**
* <p>
* BASE64字符串解碼為二進制數據
* </p>
*
* @param base64
* @return
* @throws Exception
*/
public static byte[] decode(String base64) throws Exception {
return Base64.decode(base64.getBytes());
}
/** *//**
* <p>
* 二進制數據編碼為BASE64字符串
* </p>
*
* @param bytes
* @return
* @throws Exception
*/
public static String encode(byte[] bytes) throws Exception {
return new String(Base64.encode(bytes));
}
/** *//**
* <p>
* 將文件編碼為BASE64字符串
* </p>
* <p>
* 大文件慎用，可能會導致內存溢出
* </p>
*
* @param filePath 文件絕對路徑
* @return
* @throws Exception
*/
public static String encodeFile(String filePath) throws Exception {
byte[] bytes = fileToByte(filePath);
return encode(bytes);
}
/** *//**
* <p>
* BASE64字符串轉回文件
* </p>
*
* @param filePath 文件絕對路徑
* @param base64 編碼字符串
* @throws Exception
*/
public static void decodeToFile(String filePath, String base64) throws Exception {
byte[] bytes = decode(base64);
byteArrayToFile(bytes, filePath);
}
/** *//**
* <p>
* 文件轉換為二進制數組
* </p>
*
* @param filePath 文件路徑
* @return
* @throws Exception
*/
public static byte[] fileToByte(String filePath) throws Exception {
byte[] data = new byte[0];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}
/** *//**
* <p>
* 二進制數據寫文件
* </p>
*
* @param bytes 二進制數據
* @param filePath 文件生成目錄
*/
public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
}
}
RSATester.java package security;
import java.util.Map;
public class RSATester {
static String publicKey;
static String privateKey;
static {
try {
Map<String, Object> keyMap = RSAUtils.genKeyPair();
publicKey = RSAUtils.getPublicKey(keyMap);
privateKey = RSAUtils.getPrivateKey(keyMap);
System.err.println("公鑰: \n\r" + publicKey);
System.err.println("私鑰： \n\r" + privateKey);
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception {
test();
testSign();
}
static void test() throws Exception {
System.err.println("公鑰加密——私鑰解密");
String source = "這是一行沒有任何意義的文字，你看完了等于沒看，不是嗎？";
System.out.println("\r加密前文字：\r\n" + source);
byte[] data = source.getBytes();
byte[] encodedData = RSAUtils.encryptByPublicKey(data, publicKey);
System.out.println("加密后文字：\r\n" + new String(encodedData));
byte[] decodedData = RSAUtils.decryptByPrivateKey(encodedData, privateKey);
String target = new String(decodedData);
System.out.println("解密后文字: \r\n" + target);
}
static void testSign() throws Exception {
System.err.println("私鑰加密——公鑰解密");
String source = "這是一行測試RSA數字簽名的無意義文字";
System.out.println("原文字：\r\n" + source);
byte[] data = source.getBytes();
byte[] encodedData = RSAUtils.encryptByPrivateKey(data, privateKey);
System.out.println("加密后：\r\n" + new String(encodedData));
byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, publicKey);
String target = new String(decodedData);
System.out.println("解密后: \r\n" + target);
System.err.println("私鑰簽名——公鑰驗證簽名");
String sign = RSAUtils.sign(encodedData, privateKey);
System.err.println("簽名:\r" + sign);
boolean status = RSAUtils.verify(encodedData, publicKey, sign);
System.err.println("驗證結果:\r" + status);
}
}
Feedback
# re: java RSA加密解密 回復 更多評論
2012-11-15 12:12 by
樓主不厚道，import it.sauronsoftware.base64.Base64;在哪兒？
# re: java RSA加密解密 回復 更多評論
2012-11-15 21:53 by
@yours
自己下載一下吧！百度一下javabase64-1.3.1.jar！GCD不給力，谷歌被和諧了，詛咒一下！~
# re: java RSA加密解密[未登錄] 回復 更多評論
2013-05-05 12:08 by
很不錯，不過Base64的那個其實可以直接用common-codec里面的工具，沒必要自己寫一份了，呵呵
# re: java RSA加密解密 回復 更多評論
2013-07-22 20:02 by
如果被加密的明文使用
String ming = ((char) 134) + "";
即使用asc碼大于127或者小于0的這種字符組成字符串
加密之后再解密
拿明文ming對比解密的數據，使用equal方法，會得到false，意思就是加解密肯定出了問題，我目測應該是加密的時候出的問題
這種問題如何解決，謝謝！
# re: java RSA加密解密 回復 更多評論
2014-06-03 15:08 by
數據量大了 如10M 那么無法加密和解密了
# re: java RSA加密解密 回復 更多評論
2014-08-27 15:06 by
我把數據加密存儲到本地，然后退出程序，再次進入程序，對讀取到保存的加密字符串，然后解密，這是后解密就會出亂碼問題。。可能是因為每次產生的privatekey都不同導致的，怎么解決？LZ
# re: java RSA加密解密 回復 更多評論
2015-12-06 02:30 by
沒有主函數？
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