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1package com.klyovan.textencryptioncs;
2
3import android.app.Fragment;
4import android.os.Bundle;
5import android.support.v7.app.AppCompatActivity;
6import android.util.Base64;
7import android.view.View;
8import android.widget.Button;
9import android.widget.EditText;
10import android.widget.TextView;
11import android.widget.Toast;
12
13import java.io.UnsupportedEncodingException;
14import java.security.InvalidKeyException;
15import java.security.NoSuchAlgorithmException;
16import java.security.spec.InvalidKeySpecException;
17import java.security.spec.KeySpec;
18
19import javax.crypto.Cipher;
20import javax.crypto.NoSuchPaddingException;
21import javax.crypto.SecretKey;
22import javax.crypto.SecretKeyFactory;
23import javax.crypto.spec.DESedeKeySpec;
24
25import butterknife.BindView;
26import butterknife.ButterKnife;
27
28/**
29 * A simple {@link Fragment} subclass.
30 * Created by Klyovan Ihor
31 */
32
33public class MainActivity extends AppCompatActivity implements View.OnClickListener {
34
35    //encryption type
36    public static final String EncryptionScheme = "DESede";
37    //text format
38    private static final String TestUniCodeFormat = "UTF8";
39    //
40    byte[] arrayBytes;
41    SecretKey key;
42    @BindView(R.id.et_encryption_key)
43    EditText etEncryptionKey;
44    @BindView(R.id.et_text_to_encrypt)
45    EditText etTextToEncrypt;
46    @BindView(R.id.btn_encrypt)
47    Button btnEncrypt;
48    @BindView(R.id.tv_encryption_out)
49    TextView tvEncryptionOutPut;
50    @BindView(R.id.et_encrypted_text)
51    EditText etEncryptedText;
52    @BindView(R.id.btn_decrypt)
53    Button btnDecrypt;
54    @BindView(R.id.tv_decrypted_output)
55    TextView tvDecryptionOut;
56    private KeySpec ks;
57    private SecretKeyFactory skf;
58    private Cipher cipher;
59    private String myEncryptionKey, myEncryptionScheme;
60    private String strEncrytion, strDecryption;
61
62    @Override
63    protected void onCreate(Bundle savedInstanceState) {
64        super.onCreate(savedInstanceState);
65        setContentView(R.layout.activity_main);
66        ButterKnife.bind(this);
67
68        btnEncrypt.setOnClickListener(this);
69        btnDecrypt.setOnClickListener(this);
70
71
72    }
73
74
75    @Override
76    public void onClick(View v) {
77
78        switch (v.getId()) {
79            case R.id.btn_encrypt:
80                if (etEncryptionKey.getText().length() >= 24) {
81                    if (etTextToEncrypt.getText().toString().length() > 1) {
82                        initEncryption();
83                        strEncrytion = encrypt(etTextToEncrypt.getText().toString());
84                        tvEncryptionOutPut.setText(strEncrytion);
85                        etEncryptedText.setText(strEncrytion);
86                    } else {
87                        etTextToEncrypt.setError("введите текст");
88                    }
89                } else {
90                    etEncryptionKey.setError("ключ должен быть больше 24");
91                }
92                break;
93            case R.id.btn_decrypt:
94                if (etEncryptionKey.getText().length() >= 24) {
95                    initEncryption();
96                    strDecryption = decrypt(etEncryptedText.getText().toString());
97                    tvDecryptionOut.setText(strDecryption);
98
99                } else {
100                    etEncryptionKey.setError("ключ должен быть больше 24");
101                }
102                break;
103        }
104    }
105    private void initEncryption() {
106        //getting encryption
107        myEncryptionKey = etEncryptionKey.getText().toString();
108        myEncryptionScheme = EncryptionScheme;
109        try {
110            Toast.makeText(this, "Triple DES зашифрован", Toast.LENGTH_SHORT).show();
111            arrayBytes = myEncryptionKey.getBytes(TestUniCodeFormat);
112            ks = new DESedeKeySpec(arrayBytes);
113            skf = SecretKeyFactory.getInstance(myEncryptionScheme);
114            cipher = Cipher.getInstance(myEncryptionScheme);
115            key = skf.generateSecret(ks);
116        } catch (UnsupportedEncodingException e) {
117            e.printStackTrace();
118        } catch (NoSuchPaddingException e) {
119            e.printStackTrace();
120        } catch (NoSuchAlgorithmException e) {
121            e.printStackTrace();
122        } catch (InvalidKeyException e) {
123            e.printStackTrace();
124        } catch (InvalidKeySpecException e) {
125            e.printStackTrace();
126        }
127    }
128    public String encrypt(String unencryptedString) {
129        String encryptedString = null;
130        try {
131            cipher.init(Cipher.ENCRYPT_MODE, key);
132            byte[] plainText = unencryptedString.getBytes(TestUniCodeFormat);
133            byte[] encryptedText = cipher.doFinal(plainText);
134            encryptedString = new String(Base64.encodeToString(encryptedText, Base64.DEFAULT));
135        } catch (Exception e) {
136            e.printStackTrace();
137        }
138        return encryptedString;
139    }
140
141
142    public String decrypt(String encryptedString) {
143        String decryptedText = null;
144        try {
145            cipher.init(Cipher.DECRYPT_MODE, key);
146            byte[] encryptedText = Base64.decode(encryptedString, Base64.DEFAULT);
147            byte[] plainText = cipher.doFinal(encryptedText);
148            decryptedText = new String(plainText);
149        } catch (Exception e) {
150            e.printStackTrace();
151        }
152        return decryptedText;
153    }
154
155}