3RGJQGxQ

1import java.io.UnsupportedEncodingException;
2import java.security.KeyPair;
3import java.security.KeyPairGenerator;
4import java.security.MessageDigest;
5import java.security.NoSuchAlgorithmException;
6import java.security.PrivateKey;
7import java.security.PublicKey;
8import java.util.Arrays;
9import java.util.Base64;
10
11import javax.crypto.Cipher;
12import javax.crypto.KeyGenerator;
13import javax.crypto.SecretKey;
14import javax.crypto.spec.SecretKeySpec;
15
16public class AES_RSA {
17
18    private static byte[] key;
19    private static SecretKeySpec secretKey;
20
21    public static void main(String[] args){
22        try {
23
24            //1. Generate Symmetric Key (AES with 128 bits)
25            String password = "123456";
26            KeyGenerator generator = KeyGenerator.getInstance("AES");
27            generator.init(128); // The AES key size in number of bits
28
29            setKey(password);
30
31            //2. Encrypt plain text using AES
32            String plainText = "Please encrypt me urgently...";
33            Cipher aesCipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
34            aesCipher.init(Cipher.ENCRYPT_MODE, secretKey);
35            byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
36
37            //3. Encrypt the key using RSA public key
38            KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
39            kpg.initialize(2048);
40            KeyPair keyPair = kpg.generateKeyPair();
41
42            PublicKey puKey = keyPair.getPublic();
43            PrivateKey prKey = keyPair.getPrivate();
44
45            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
46            cipher.init(Cipher.PUBLIC_KEY, puKey);
47            byte[] encryptedKey = cipher.doFinal(secretKey.getEncoded()/*Seceret Key From Step 1*/);
48
49            //4. Send encrypted data (byteCipherText) + encrypted AES Key (encryptedKey)
50            //5. On the client side, decrypt symmetric key using RSA private key
51            cipher.init(Cipher.PRIVATE_KEY, prKey);
52            byte[] decryptedKey = cipher.doFinal(encryptedKey);
53
54            //6. Decrypt the cipher using decrypted symmetric key
55            SecretKey originalKey = new SecretKeySpec(decryptedKey , 0, decryptedKey.length, "AES");
56            Cipher aesCipher1 = Cipher.getInstance("AES/ECB/PKCS5PADDING");
57            aesCipher1.init(Cipher.DECRYPT_MODE, originalKey);
58            byte[] bytePlainText = aesCipher1.doFinal(byteCipherText);
59            String plainText1 = new String(bytePlainText);
60
61            //7. Done! 'Please encrypt me urgently...'
62            System.out.println(plainText1);
63
64        }catch (Exception e) {}
65    }
66
67
68    public static void setKey(String myKey)
69    {
70        MessageDigest sha = null;
71        try {
72            key = myKey.getBytes("UTF-8");
73            sha = MessageDigest.getInstance("SHA-256");
74            key = sha.digest(key);
75            key = Arrays.copyOf(key, 16);
76            secretKey = new SecretKeySpec(key, "AES");
77        }
78        catch (NoSuchAlgorithmException e) {
79            e.printStackTrace();
80        }
81        catch (UnsupportedEncodingException e) {
82            e.printStackTrace();
83        }
84    }
85}