Versio 1.0.2

.idea/deploymentTargetDropDown.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="deploymentTargetDropDown">
+    <targetSelectedWithDropDown>
+      <Target>
+        <type value="QUICK_BOOT_TARGET" />
+        <deviceKey>
+          <Key>
+            <type value="VIRTUAL_DEVICE_PATH" />
+            <value value="$USER_HOME$/.android/avd/Nexus_4_API_22.avd" />
+          </Key>
+        </deviceKey>
+      </Target>
+    </targetSelectedWithDropDown>
+    <timeTargetWasSelectedWithDropDown value="2024-03-22T09:22:07.756257223Z" />
+  </component>
+</project>

README.md

@@ -1,5 +1,5 @@
 Ĉi tiu paĝo estas en aliaj lingvoj:
-[Rusa](README_RU.md)
+[Русский](README_RU.md)
 
 ---
 # Sekreto por Androido
@@ -28,4 +28,4 @@ Kaŝu sekretan mesaĝon en teksto!
 ---
 ## Komputilo
 
-[Sekreto](https://git.disroot.org/1010/Sekreto)
+[Sekreto](https://git.disroot.org/1010/Sekreto)

app/build.gradle.kts

@@ -11,8 +11,8 @@ android {
         applicationId = "com.example.sekreto"
         minSdk = 21
         targetSdk = 33
-        versionCode = 2
-        versionName = "1.0.1"
+        versionCode = 3
+        versionName = "1.0.2"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables {

app/src/main/java/com/example/sekreto/Crypto.kt

@@ -1,97 +1,118 @@
 package com.example.sekreto
 
+import java.nio.ByteBuffer
+import java.nio.charset.Charset
 import java.security.SecureRandom
+import javax.crypto.BadPaddingException
 import javax.crypto.Cipher
 import javax.crypto.SecretKey
 import javax.crypto.SecretKeyFactory
-import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.GCMParameterSpec
 import javax.crypto.spec.PBEKeySpec
 import javax.crypto.spec.SecretKeySpec
 
 class Crypto {
 
-    companion object {
-        private const val KEY_SIZE_BITS = 128
-        private const val ITERATION_COUNT = 10000
-        private const val SALT_SIZE_BYTES = 16
-        private const val AES_KEY_SIZE_BYTES = KEY_SIZE_BITS / 8
-        private const val IV_SIZE_BYTES = 16
+    private val TAG_LENGTH = 16
+    private val IV_LENGTH = 12
+    private val SALT_LENGTH = 16
+    private val KEY_LENGTH = 32
+    private val ITERATIONS = 65535
 
-        private fun generateSalt(): ByteArray {
-            val secureRandom = SecureRandom()
-            val salt = ByteArray(SALT_SIZE_BYTES)
-            secureRandom.nextBytes(salt)
-            return salt
+    private val CIPHER_ALGORITHM = "AES/GCM/NoPadding"
+    private val FACTORY_INSTANCE = "PBKDF2WithHmacSHA1"
+    private val UTF_8: Charset = Charsets.UTF_8
+
+    private fun getSecretKey(password: String, salt: ByteArray): SecretKey {
+        val spec = PBEKeySpec(password.toCharArray(), salt, ITERATIONS, KEY_LENGTH * 8)
+
+        val factory = SecretKeyFactory.getInstance(FACTORY_INSTANCE)
+        return SecretKeySpec(factory.generateSecret(spec).encoded, "AES")
+    }
+
+    private fun getRandomNonce(length: Int): ByteArray {
+        val nonce = ByteArray(length)
+        SecureRandom().nextBytes(nonce)
+        return nonce
+    }
+
+    private fun initCipher(mode: Int, secretKey: SecretKey, iv: ByteArray): Cipher {
+        val cipher = Cipher.getInstance(CIPHER_ALGORITHM)
+        cipher.init(mode, secretKey, GCMParameterSpec(TAG_LENGTH * 8, iv))
+        return cipher
+    }
+
+    private fun byte2hex(byteArray: ByteArray): String {
+        val stringBuilder = StringBuilder()
+        for (byte in byteArray) {
+            val hex = String.format("%02X", byte)
+            stringBuilder.append(hex)
         }
+        return stringBuilder.toString()
+    }
 
-        private fun generateKey(password: String, salt: ByteArray): SecretKey {
-            val keySpec = PBEKeySpec(password.toCharArray(), salt, ITERATION_COUNT, AES_KEY_SIZE_BYTES * 8)
-            val secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1")
-            val secretKey = secretKeyFactory.generateSecret(keySpec)
-            return SecretKeySpec(secretKey.encoded, "AES")
+    private fun hex2byte(hexString: String): ByteArray {
+        val byteArray = ByteArray(hexString.length / 2)
+        for (i in byteArray.indices) {
+            val index = i * 2
+            val hex = hexString.substring(index, index + 2)
+            val byte = hex.toInt(16).toByte()
+            byteArray[i] = byte
         }
+        return byteArray
+    }
 
-        private fun generateIV(): IvParameterSpec {
-            val iv = ByteArray(IV_SIZE_BYTES)
-            SecureRandom().nextBytes(iv)
-            return IvParameterSpec(iv)
-        }
+    private fun getAESKeyFromPassword(password: CharArray, salt: ByteArray): SecretKey {
+        val factory = SecretKeyFactory.getInstance(FACTORY_INSTANCE)
+        val spec = PBEKeySpec(password, salt, ITERATIONS, KEY_LENGTH * 8)
+        val secret = SecretKeySpec(factory.generateSecret(spec).encoded, "AES")
+        return secret
+    }
 
-        fun byte2hex(byteArray: ByteArray): String {
-            val stringBuilder = StringBuilder()
-            for (byte in byteArray) {
-                val hex = String.format("%02X", byte)
-                stringBuilder.append(hex)
-            }
-            return stringBuilder.toString()
-        }
+    fun encrypt(password: String, plainMessage: String): String {
+        val salt = getRandomNonce(SALT_LENGTH)
+        val secretKey = getSecretKey(password, salt)
 
-        fun hex2byte(hexString: String): ByteArray {
-            val byteArray = ByteArray(hexString.length / 2)
-            for (i in byteArray.indices) {
-                val index = i * 2
-                val hex = hexString.substring(index, index + 2)
-                val byte = hex.toInt(16).toByte()
-                byteArray[i] = byte
-            }
-            return byteArray
-        }
+        val iv = getRandomNonce(IV_LENGTH)
 
-        fun encrypt(plaintext: String, password: String): String {
-            val salt = generateSalt()
-            val secretKey = generateKey(password, salt)
+        val cipher = initCipher(Cipher.ENCRYPT_MODE, secretKey, iv)
 
-            val iv = generateIV()
-            val cipher = Cipher.getInstance("AES/CBC/PKCS7Padding")
-            cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv)
+        val encryptedMessageByte = cipher.doFinal(plainMessage.toByteArray(UTF_8))
 
-            val ciphertext = cipher.doFinal(plaintext.toByteArray(Charsets.UTF_8))
-            val encryptedData = ByteArray(salt.size + iv.iv.size + ciphertext.size)
+        val cipherByte = ByteBuffer.allocate(salt.size + iv.size + encryptedMessageByte.size)
+            .put(salt)
+            .put(iv)
+            .put(encryptedMessageByte)
+            .array()
 
-            System.arraycopy(salt, 0, encryptedData, 0, salt.size)
-            System.arraycopy(iv.iv, 0, encryptedData, salt.size, iv.iv.size)
-            System.arraycopy(ciphertext, 0, encryptedData, salt.size + iv.iv.size, ciphertext.size)
+        return byte2hex(cipherByte)
+    }
 
-            return byte2hex(encryptedData)
-        }
+    fun decrypt(cipherContent: String, password: String): String? {
+        try {
+            val decode = hex2byte(cipherContent)
+            val byteBuffer = ByteBuffer.wrap(decode)
 
-        fun decrypt(hexString: String, password: String): String? {
-            try {
-                val ciphertext = hex2byte(hexString)
-                val salt = ciphertext.copyOfRange(0, SALT_SIZE_BYTES)
-                val iv = ciphertext.copyOfRange(SALT_SIZE_BYTES, SALT_SIZE_BYTES + IV_SIZE_BYTES)
-                val encryptedData = ciphertext.copyOfRange(SALT_SIZE_BYTES + IV_SIZE_BYTES, ciphertext.size)
+            val salt = ByteArray(SALT_LENGTH)
+            byteBuffer.get(salt)
 
-                val secretKey = generateKey(password, salt)
+            val iv = ByteArray(IV_LENGTH)
+            byteBuffer.get(iv)
 
-                val cipher = Cipher.getInstance("AES/CBC/PKCS7Padding")
-                cipher.init(Cipher.DECRYPT_MODE, secretKey, IvParameterSpec(iv))
+            val content = ByteArray(byteBuffer.remaining())
+            byteBuffer.get(content)
 
-                val decryptedData = cipher.doFinal(encryptedData)
-                return decryptedData.toString(Charsets.UTF_8)
-            } catch (e: Exception) {
-                return null
-            }
+            val cipher = Cipher.getInstance(CIPHER_ALGORITHM)
+            val aesKeyFromPassword = getAESKeyFromPassword(password.toCharArray(), salt)
+            cipher.init(Cipher.DECRYPT_MODE, aesKeyFromPassword, GCMParameterSpec(TAG_LENGTH * 8, iv))
+            val plainText = cipher.doFinal(content)
+            return String(plainText, UTF_8)
+        } catch (e: BadPaddingException) {
+            e.printStackTrace()
+            return null
+        } catch (e: Exception) {
+            e.printStackTrace()
+            return null
         }
     }
 }

app/src/main/java/com/example/sekreto/HideActivity.kt

@@ -60,7 +60,7 @@ class HideActivity : AppCompatActivity() {
                 val warningDialog = WarningDialog()
                 warningDialog.show(supportFragmentManager, "warning_dialog")
             } else {
-                val hex = Crypto.encrypt(secret, password)
+                val hex = Crypto().encrypt(password, secret)
                 val hiding = Stegano.hex2hid(hex)
 
                 val startIndex = pub_msg.length / 2

app/src/main/java/com/example/sekreto/ViewActivity.kt

@@ -52,8 +52,7 @@ class ViewActivity : AppCompatActivity() {
 
             if (result.isNotEmpty() && password.isNotEmpty()) {
                 val extraction = Stegano.hid2hex(result)
-
-                val decrypt = Crypto.decrypt(extraction, password)
+                val decrypt = Crypto().decrypt(extraction, password)
 
                 if (decrypt != null) {