Java 非對稱式加密

標籤：

 1 package test; 2  3 import java.io.FileInputStream; 4 import java.io.FileOutputStream; 5 import java.io.ObjectInputStream; 6 import java.io.ObjectOutputStream; 7 import java.security.Key; 8 import java.security.KeyPair; 9 import java.security.KeyPairGenerator;10 11 import javax.crypto.Cipher;12 13 public class testcase {14 15     public static void main(String[] args) throws Exception {16         PublicEnrypt();17         privateDecrypt();18 19     }20     //加密21     public static void PublicEnrypt() throws Exception{22         // 執行個體化加密工具，使用RSA演算法23         Cipher cipher=Cipher.getInstance("RSA");24         // 執行個體化Key25         KeyPairGenerator keypairGenerator=KeyPairGenerator.getInstance("RSA");26         // 獲得一對鑰匙27         KeyPair keyPair=keypairGenerator.generateKeyPair();28         // 擷取公開金鑰29         Key publicKey=keyPair.getPublic();30         // 擷取私密金鑰31         Key privateKey=keyPair.getPrivate();32         // 用公開金鑰加密33         cipher.init(Cipher.ENCRYPT_MODE, publicKey);34         byte []result =cipher.doFinal("資料內容".getBytes("UTF-8"));35         // 將私密金鑰寫入檔案36         saveKey(privateKey,"zxx_private.key");37         // 加密後的資料存放區38         saveData(result,"public_encryt.dat");        39         System.out.println(new String(result,"UTF-8"));40     }41     //解密42     public static void privateDecrypt() throws Exception{43         //執行個體化加密工具44         Cipher cipher=Cipher.getInstance("RSA");45         // 擷取私密金鑰46         Key privateKey=readKey("zxx_private.key");47         // 擷取加密後的資訊48         byte[] src=readData("public_encryt.dat");49         // 用私密金鑰解密50         cipher.init(Cipher.DECRYPT_MODE, privateKey);51         byte[] result=cipher.doFinal(src);52         System.out.println(new String(result,"UTF-8"));53     }54     // 儲存資料55     public static void saveData(byte[] result,String fileName) throws Exception{56         FileOutputStream fosData=new FileOutputStream(fileName);57         fosData.write(result);58         fosData.close();59     }60     // 儲存密鑰61     public static void saveKey(Key key,String fileName) throws Exception{62         FileOutputStream fosKey=new FileOutputStream(fileName);63         ObjectOutputStream oosSecretKey=new ObjectOutputStream(fosKey);64         oosSecretKey.writeObject(key);65         oosSecretKey.close();66         fosKey.close();    67     }68       //讀取密鑰69     public static Key readKey(String fileName) throws Exception{70         FileInputStream fisKey=new FileInputStream(fileName);71         ObjectInputStream oisKey=new ObjectInputStream(fisKey);72         Key key=(Key)oisKey.readObject();73         oisKey.close();74         fisKey.close();75         return key;76     }77        // 讀取資料78     public static byte[] readData(String fileName) throws Exception{79         FileInputStream fisDat=new FileInputStream(fileName);80         byte[] src=new byte[fisDat.available()];81         int len=fisDat.read(src);82         int total=0;83         while(total<src.length){84             total+=len;85             len=fisDat.read(src, total, src.length-total);86         }87         fisDat.close();88          return src;89     }90     91 }

 

Java 非對稱式加密