EVayPGZe

1import java.nio.file.Files; 
2import java.nio.file.Paths; 
3import java.security.*; 
4import javax.crypto.*; 
5import java.util.*; 
6import java.io.*; 
7
8public class passenc { 
9
10     String FileName = "encryptedtext12.txt"; //save encrypted text 
11        String FileName2 = "decryptedtext12.txt"; //save decrypted text 
12	 
13	Cipher AesCipher ; 
14	byte[] byteText ;  
15    public void enc(String tobe,String enctype) 
16    { 
17            
18        try{ 
19    	   //convert message to bytestream 
20	 
21        //AES cipher 
22                AesCipher= Cipher.getInstance(enctype); 
23		byteText=tobe.getBytes(); 
24                KeyGenerator KeyGen = KeyGenerator.getInstance(enctype);  //define key  generator 
25		KeyGen.init(128);                                           //initalize key generator 
26
27		SecretKey SecKey = KeyGen.generateKey();                //private key algorithm AES only one key used 
28
29		AesCipher.init(Cipher.ENCRYPT_MODE, SecKey);            //initialize AES encryption 
30		byte[] byteCipherText = AesCipher.doFinal(byteText);    //perform encryption 
31		Files.write(Paths.get(FileName), byteCipherText);       //write result to file 
32
33		byte[] cipherText = Files.readAllBytes(Paths.get(FileName)); 
34
35		AesCipher.init(Cipher.DECRYPT_MODE, SecKey);            //initialize AES decryption 
36		byte[] bytePlainText = AesCipher.doFinal(cipherText);   //perform decryption 
37		Files.write(Paths.get(FileName2), bytePlainText);       //write result to file 
38
39        } 
40        catch(Exception e) 
41        { 
42            e.printStackTrace(); 
43        } 
44    }	 
45    public void end(String tobe) 
46    { 
47        try{ 
48                AesCipher =Cipher.getInstance("RSA"); 
49                byteText=tobe.getBytes(); 
50                KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA"); 
51		KeyPair myPair = kpg.generateKeyPair();             
52		 
53		AesCipher.init(Cipher.ENCRYPT_MODE, myPair.getPublic());        //get public key tp encrypt 
54		byte[] byteCipherText = AesCipher.doFinal(byteText);            //perform encryption 
55		Files.write(Paths.get(FileName), byteCipherText);               //write to file 
56		 
57		byte[] cipherText = Files.readAllBytes(Paths.get(FileName));   
58		 
59		AesCipher.init(Cipher.DECRYPT_MODE, myPair.getPrivate());        //get private key to decrypt 
60		byte[] bytePlainText = AesCipher.doFinal(cipherText);           //perform decryption 
61		Files.write(Paths.get(FileName2), bytePlainText); 
62    } 
63        catch(Exception e){ 
64            e.printStackTrace(); 
65        } 
66    } 
67    public static void main(String[] args) throws Exception { 
68        	passenc obj=new passenc(); 
69        	System.out.println("Enter encryption type : 1 - AES 2 - RSA"); 
70        	BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); 
71                String enctype=br.readLine(); 
72                  
73                System.out.println("Enter message :"); 
74                String tobe=br.readLine(); 
75                if(enctype.equals("AES")){ 
76                obj.enc(tobe, enctype); 
77                } 
78                else{ 
79                obj.end(tobe); 
80                } 
81                
82    } 
83}