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1/*
2 * You need to install
3 * Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files
4 * for using 256-bit key
5 */
6
7import java.util.Arrays;
8import java.util.Base64;
9import javax.crypto.Cipher;
10import javax.crypto.spec.IvParameterSpec;
11import javax.crypto.spec.SecretKeySpec;
12// import javax.xml.bind.DatatypeConverter;
13
14public class AES256Test {
15    private String encrypt(String clearText, String secretKey, String initVector) {
16        try {
17            byte[] bytePass = secretKey.getBytes("utf-8");
18            byte[] byteV = initVector.getBytes("utf-8");
19
20            byte[] byteKey = Arrays.copyOf(bytePass, 32);
21            byte[] byteIV = Arrays.copyOf(byteV, 16);
22            // System.out.println(DatatypeConverter.printHexBinary(byteKey));
23            // System.out.println(DatatypeConverter.printHexBinary(byteIV));
24
25            SecretKeySpec skeySpec = new SecretKeySpec(byteKey, "AES");
26            IvParameterSpec ivSpec = new IvParameterSpec(byteIV);
27
28            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
29            cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivSpec);
30
31            byte[] byteText = clearText.getBytes("utf-8");
32            byte[] buf = cipher.doFinal(byteText);
33
34            byte[] byteBase64 = Base64.getEncoder().encode(buf);
35            String data = new String(byteBase64);
36
37            return data;
38        }
39        catch(Exception ex) {
40            return ex.getMessage();
41        }
42    }
43
44    private String decrypt(String data, String secretKey, String initVector) {
45        try {
46            byte[] byteData = Base64.getDecoder().decode(data.getBytes("utf-8"));
47            byte[] bytePass = secretKey.getBytes("utf-8");
48            byte[] byteV = initVector.getBytes("utf-8");
49
50            byte[] byteKey = Arrays.copyOf(bytePass, 32);
51            byte[] byteIV = Arrays.copyOf(byteV, 16);
52
53            SecretKeySpec skeySpec = new SecretKeySpec(byteKey, "AES");
54            IvParameterSpec ivSpec = new IvParameterSpec(byteIV);
55
56            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
57            cipher.init(Cipher.DECRYPT_MODE, skeySpec, ivSpec);
58
59            byte[] byteText = cipher.doFinal(byteData);
60            String clearText = new String(byteText);
61
62            return clearText;
63        }
64        catch(Exception ex) {
65            return ex.getMessage();
66        }
67    }
68
69    public static void main(String[] args) {
70        String clearText = "hello";
71        String secretKey = "TheBestSecretKey";
72        String initVector = "1234567890abcdef";
73
74        String data = new AES256Test().encrypt(clearText, secretKey, initVector);
75        clearText = new AES256Test().decrypt(data, secretKey, initVector);
76
77        System.out.println("Encrypted String: " + data);
78        System.out.println("Decrypted: " + clearText);
79    }
80}