kYbj08t7

1Klasa potrzebna do inkrypcji i dekrypcji 
2package com.example.notesh;
3
4
5import android.content.Context;
6import android.content.SharedPreferences;
7import android.os.Build;
8import android.security.keystore.KeyGenParameterSpec;
9import android.security.keystore.KeyProperties;
10import android.util.Base64;
11
12import androidx.annotation.RequiresApi;
13
14import java.io.IOException;
15import java.security.InvalidAlgorithmParameterException;
16import java.security.KeyStore;
17import java.security.KeyStoreException;
18import java.security.NoSuchAlgorithmException;
19import java.security.NoSuchProviderException;
20import java.security.UnrecoverableKeyException;
21import java.security.cert.CertificateException;
22
23import javax.crypto.Cipher;
24import javax.crypto.KeyGenerator;
25import javax.crypto.NoSuchPaddingException;
26import javax.crypto.SecretKey;
27import javax.crypto.spec.IvParameterSpec;
28
29
30public class SecretKeyUtils {
31
32    @RequiresApi(api = Build.VERSION_CODES.M)
33    public static void CheckAndGeneratePassword()
34    {
35        try {
36            SecretKey key = getSecretKey();
37            if (key == null)
38            {
39                generateSecretKey(new KeyGenParameterSpec.Builder(
40                        "NoteHSecretKey",
41                        KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
42                        .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
43                        .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
44                        .build());
45            }
46        } catch (Exception e)
47        {
48            System.out.println("CheckAndGeneratePassword: " + e.toString());
49        }
50    }
51
52
53
54    @RequiresApi(api = Build.VERSION_CODES.M)
55    public static void generateSecretKey(KeyGenParameterSpec keyGenParameterSpec) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidAlgorithmParameterException {
56        KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
57        keyGenerator.init(keyGenParameterSpec);
58        keyGenerator.generateKey();
59    }
60
61    public static SecretKey getSecretKey() throws KeyStoreException, CertificateException, NoSuchAlgorithmException, IOException, UnrecoverableKeyException {
62        KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
63
64       
65        keyStore.load(null);
66        return ((SecretKey)keyStore.getKey("NoteHSecretKey", null));
67    }
68
69    public static Cipher getCipher() throws NoSuchPaddingException, NoSuchAlgorithmException {
70        return Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/"
71                + KeyProperties.BLOCK_MODE_CBC + "/"
72                + KeyProperties.ENCRYPTION_PADDING_PKCS7);
73    }
74
75    public static String encryptNote(String note, Context context)
76    {
77        try {
78
79
80            Cipher cipher = getCipher();
81            SecretKey secretKey = getSecretKey();
82            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
83
84            byte[] iv = cipher.getIV();
85
86            SharedPreferences sharedPref = context.getSharedPreferences("szyfr", Context.MODE_PRIVATE);
87            SharedPreferences.Editor editor = sharedPref.edit();
88
89            editor.putString("ivi", Base64.encodeToString(iv, Base64.DEFAULT));
90            editor.commit();
91
92            byte[] encryptedInfo = cipher.doFinal(note.getBytes("UTF-8"));
93
94            return Base64.encodeToString(encryptedInfo, Base64.NO_WRAP);
95        }catch (Exception e)
96        {
97            System.out.println("Error while encrypting: " + e.toString());
98        }
99
100        return "";
101    }
102
103    public static String decryptNote(String note, Context context)
104    {
105        try {
106
107            SharedPreferences sharedPref = context.getSharedPreferences("note",Context.MODE_PRIVATE);
108            String ivArray = sharedPref.getString("ivi","");
109            byte[] iv = Base64.decode(ivArray, Base64.DEFAULT);
110
111            Cipher cipher = getCipher();
112            SecretKey secretKey = getSecretKey();
113            cipher.init(Cipher.DECRYPT_MODE, secretKey,new IvParameterSpec(iv));
114            return new String(cipher.doFinal(Base64.decode(note,Base64.NO_WRAP)));
115        }catch (Exception e)
116        {
117            System.out.println("Error while encrypting: " + e.toString());
118        }
119
120        return "";
121    }
122