Code simplify

src/main/kotlin/core/security/MasterPasswordManager.kt

@@ -12,61 +12,31 @@ import javax.crypto.spec.SecretKeySpec
 
 object MasterPasswordManager {
 
-    /**
-     * Converts a string to a SecureString equivalent in Kotlin (emulated).
-     * Kotlin doesn't have a `SecureString`, so use char arrays for sensitive data.
-     */
-    fun convertToSecureString(value: String): CharArray {
-        return value.toCharArray()
-    }
+    fun convertToSecureString(value: String): CharArray = value.toCharArray()
 
-    /**
-     * Converts a char array back to a regular string.
-     */
-    fun convertToUnsecureString(secureString: CharArray): String {
-        return String(secureString)
-    }
+    fun convertToUnsecureString(secureString: CharArray): String = String(secureString)
 
-    /**
-     * Encrypts a string using AES (Advanced Encryption Standard) algorithm.
-     */
     fun encryptString(plainText: String, key: ByteArray): String {
         val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
-        val iv = ByteArray(cipher.blockSize)
-        SecureRandom().nextBytes(iv)
-        val ivSpec = IvParameterSpec(iv)
-        cipher.init(Cipher.ENCRYPT_MODE, SecretKeySpec(key, "AES"), ivSpec)
-
+        val iv = ByteArray(cipher.blockSize).apply { SecureRandom().nextBytes(this) }
+        cipher.init(Cipher.ENCRYPT_MODE, SecretKeySpec(key, "AES"), IvParameterSpec(iv))
         val encrypted = cipher.doFinal(plainText.toByteArray(StandardCharsets.UTF_8))
-        val combined = iv + encrypted
-
-        return Base64.getEncoder().encodeToString(combined)
+        return Base64.getEncoder().encodeToString(iv + encrypted)
     }
 
-    /**
-     * Decrypts a string that was encrypted using AES (Advanced Encryption Standard) algorithm.
-     */
     fun decryptString(encryptedText: String, key: ByteArray): String {
         val combined = Base64.getDecoder().decode(encryptedText)
         val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
         val iv = combined.copyOf(cipher.blockSize)
         val encrypted = combined.copyOfRange(cipher.blockSize, combined.size)
-        val ivSpec = IvParameterSpec(iv)
-
-        cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(key, "AES"), ivSpec)
-        val decrypted = cipher.doFinal(encrypted)
-
-        return String(decrypted, StandardCharsets.UTF_8)
+        cipher.init(Cipher.DECRYPT_MODE, SecretKeySpec(key, "AES"), IvParameterSpec(iv))
+        return String(cipher.doFinal(encrypted), StandardCharsets.UTF_8)
     }
 
-    /**
-     * Derives a cryptographic key from a password and a secret key using PBKDF2 algorithm.
-     */
     fun getKey(secretKey: String): ByteArray {
         val salt = secretKey.toByteArray(StandardCharsets.UTF_8)
         val spec: KeySpec = PBEKeySpec(secretKey.toCharArray(), salt, 10000, 256)
-        val factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256")
-        return factory.generateSecret(spec).encoded
+        return SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256").generateSecret(spec).encoded
     }
 
-}
+}