参加比赛做了面对医患的作品，中间用到RSA了，因为不止要加密字符串，还要加密图片，病例等。但java自带的类限制了加密长度。。。所以要采用分割加密，分割解密，不然会出现Data must not be longer than 117 bytes之类的问题
然后我就各种谷歌。。stackoverflow。。。就成功了
项目目录结构。。jdk是1.8，java8中带有Rsa的类
1.GetKey(读取公钥和私钥)
2.RsaTool(文件的加密和解密)
3.TesRsa(测试)
上代码
GetKey.java
package com.test;
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.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.Date;
import java.io.*;
import java.nio.ByteBuffer;
import javax.crypto.Cipher;
public class GetKey {
//生成公私钥
public static void geration(){KeyPairGenerator keyPairGenerator;
try {
keyPairGenerator = KeyPairGenerator.getInstance("RSA");
SecureRandom secureRandom = new SecureRandom(new Date().toString().getBytes());
keyPairGenerator.initialize(1024, secureRandom);
KeyPair keyPair = keyPairGenerator.genKeyPair();
byte[] publicKeyBytes = keyPair.getPublic().getEncoded();
FileOutputStream fos = new FileOutputStream("c:/key/PUBLIC_KEY.key");
fos.write(publicKeyBytes);
fos.close();
byte[] privateKeyBytes = keyPair.getPrivate().getEncoded();
fos = new FileOutputStream("c:/key/PRIVATE_KEY.key");
fos.write(privateKeyBytes);
fos.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static PublicKey getPublicKey(String filename) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int)f.length()];
dis.readFully(keyBytes);
dis.close();
X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePublic(spec);
}
public static PrivateKey getPrivateKey(String filename)throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int)f.length()];
dis.readFully(keyBytes);
dis.close();
PKCS8EncodedKeySpec spec =new PKCS8EncodedKeySpec(keyBytes);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePrivate(spec);
}
}
2.RsaTool.java
package com.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import javax.crypto.Cipher;
public class RsaTool {
public static void enCryptFor(File file)
{
try
{
//得到要加密文件
FileInputStream fileInputStream = new FileInputStream(file);
byte[] decryptedFileBytes = new byte[fileInputStream.available()];
fileInputStream.read(decryptedFileBytes);
fileInputStream.close();
//得到公钥
PublicKey publicKey =(RSAPublicKey)GetKey.getPublicKey("c:/key/PUBLIC_KEY.key");
//加密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
//Rsa要求不得超过117
int decryptedFileBytesChunkLength = 100;
int numberenOfDecryptedChunks = (decryptedFileBytes.length-1) / decryptedFileBytesChunkLength + 1;
//RSA需要输出128
int encryptedFileBytesChunkLength = 128;
int encryptedFileBytesLength = numberenOfDecryptedChunks * encryptedFileBytesChunkLength;
byte[] encryptedFileBytes = new byte[ encryptedFileBytesLength ];
int decryptedByteIndex = 0;
int encryptedByteIndex = 0;
for(int i = 0; i < numberenOfDecryptedChunks; i++)
{
if(i < numberenOfDecryptedChunks - 1)
{
encryptedByteIndex = encryptedByteIndex + cipher.doFinal(decryptedFileBytes, decryptedByteIndex, decryptedFileBytesChunkLength, encryptedFileBytes, encryptedByteIndex);
decryptedByteIndex = decryptedByteIndex + decryptedFileBytesChunkLength;
}
else
{
cipher.doFinal(decryptedFileBytes, decryptedByteIndex, decryptedFileBytes.length - decryptedByteIndex, encryptedFileBytes, encryptedByteIndex);
}
}
//保存
FileOutputStream fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(encryptedFileBytes);
fileOutputStream.flush();
fileOutputStream.close();
System.out.println("length: "+ decryptedFileBytes.length);
System.out.println("length: "+ encryptedFileBytes.length);
System.out.println("Encryption done");
}
catch (Exception e)
{
e.printStackTrace();
}
}
public static void deCryptFor(File file)
{
try
{
//得到要解密文件
FileInputStream fileInputStream = new FileInputStream(file);
byte[] encryptedFileBytes = new byte[fileInputStream.available()];
fileInputStream.read(encryptedFileBytes);
fileInputStream.close();
//得到密钥
PrivateKey privateKey =(RSAPrivateKey)GetKey.getPrivateKey("c:/key/PRIVATE_KEY.key");
//解密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
//RSA 需要输出128
int encryptedFileBytesChunkLength = 128;
int numberOfEncryptedChunks = encryptedFileBytes.length / encryptedFileBytesChunkLength;
//rsa每次输入长度不得超过117
int decryptedFileBytesChunkLength = 100;
int decryptedFileBytesLength = numberOfEncryptedChunks * encryptedFileBytesChunkLength;
byte[] decryptedFileBytes = new byte[decryptedFileBytesLength];
int decryptedByteIndex = 0;
int encryptedByteIndex = 0;
for(int i = 0; i < numberOfEncryptedChunks; i++)
{
if( i < numberOfEncryptedChunks -1 )
{
decryptedByteIndex = decryptedByteIndex + cipher.doFinal(encryptedFileBytes, encryptedByteIndex, encryptedFileBytesChunkLength, decryptedFileBytes, decryptedByteIndex);
encryptedByteIndex = encryptedByteIndex + encryptedFileBytesChunkLength;
}
else
{
decryptedByteIndex = decryptedByteIndex + cipher.doFinal(encryptedFileBytes, encryptedByteIndex, encryptedFileBytes.length - encryptedByteIndex, decryptedFileBytes, decryptedByteIndex);
}
}
//保存解密文件
FileOutputStream fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(decryptedFileBytes);
fileOutputStream.flush();
fileOutputStream.close();
System.out.println("length: "+ encryptedFileBytes.length);
System.out.println("length: "+ decryptedFileBytes.length);
System.out.println("Decryption done");
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
3.TestRsa
package com.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.security.PrivateKey;
import java.security.PublicKey;
import javax.crypto.Cipher;
public class TestRsa {
public static void main(String[] args) {
File file=new File("c:/key/123.xls");
RsaTool tool=new RsaTool();
tool.enCryptFor(file);
tool.deCryptFor(file);
}
}
测试结果：
未加密前-》
加密后-》
解密-》
欢迎大家指正。。。