Refactor randomized password generator into a separate module (#1663)

7 files changed, 52 insertions, 416 deletions

diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 443121cf..e171a814 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -79,6 +79,7 @@ dependencies {
   implementation(projects.formatCommon)
   implementation(projects.openpgpKtx)
   implementation(projects.passgen.diceware)
+  implementation(projects.passgen.random)
   implementation(libs.androidx.activity.ktx)
   implementation(libs.androidx.appcompat)
   implementation(libs.androidx.autofill)
diff --git a/app/src/main/java/dev/msfjarvis/aps/ui/dialogs/PasswordGeneratorDialogFragment.kt b/app/src/main/java/dev/msfjarvis/aps/ui/dialogs/PasswordGeneratorDialogFragment.kt
index ab51cc4e..a21e9a6a 100644
--- a/app/src/main/java/dev/msfjarvis/aps/ui/dialogs/PasswordGeneratorDialogFragment.kt
+++ b/app/src/main/java/dev/msfjarvis/aps/ui/dialogs/PasswordGeneratorDialogFragment.kt
@@ -14,6 +14,7 @@ import android.widget.EditText
 import android.widget.Toast
 import androidx.annotation.IdRes
 import androidx.appcompat.widget.AppCompatTextView
+import androidx.core.content.edit
 import androidx.core.os.bundleOf
 import androidx.fragment.app.DialogFragment
 import androidx.fragment.app.setFragmentResult
@@ -23,11 +24,12 @@ import com.github.michaelbull.result.runCatching
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import dev.msfjarvis.aps.R
 import dev.msfjarvis.aps.databinding.FragmentPwgenBinding
+import dev.msfjarvis.aps.passgen.random.MaxIterationsExceededException
+import dev.msfjarvis.aps.passgen.random.NoCharactersIncludedException
+import dev.msfjarvis.aps.passgen.random.PasswordGenerator
+import dev.msfjarvis.aps.passgen.random.PasswordLengthTooShortException
+import dev.msfjarvis.aps.passgen.random.PasswordOption
 import dev.msfjarvis.aps.ui.crypto.PasswordCreationActivity
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator.generate
-import dev.msfjarvis.aps.util.pwgen.PasswordGenerator.setPrefs
-import dev.msfjarvis.aps.util.pwgen.PasswordOption
 import dev.msfjarvis.aps.util.settings.PreferenceKeys
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.launchIn
@@ -96,10 +98,23 @@ class PasswordGeneratorDialogFragment : DialogFragment() {
   }
 
   private fun generate(passwordField: AppCompatTextView) {
-    setPreferences()
+    val passwordOptions = getSelectedOptions()
+    val passwordLength = getLength()
+    setPrefs(requireContext(), passwordOptions, passwordLength)
     passwordField.text =
-      runCatching { generate(requireContext().applicationContext) }.getOrElse { e ->
-        Toast.makeText(requireActivity(), e.message, Toast.LENGTH_SHORT).show()
+      runCatching { PasswordGenerator.generate(passwordOptions, passwordLength) }.getOrElse {
+        exception ->
+        val errorText =
+          when (exception) {
+            is MaxIterationsExceededException ->
+              requireContext().getString(R.string.pwgen_max_iterations_exceeded)
+            is NoCharactersIncludedException ->
+              requireContext().getString(R.string.pwgen_no_chars_error)
+            is PasswordLengthTooShortException ->
+              requireContext().getString(R.string.pwgen_length_too_short_error)
+            else -> requireContext().getString(R.string.pwgen_some_error_occurred)
+          }
+        Toast.makeText(requireActivity(), errorText, Toast.LENGTH_SHORT).show()
         ""
       }
   }
@@ -108,18 +123,34 @@ class PasswordGeneratorDialogFragment : DialogFragment() {
     return requireDialog().findViewById<CheckBox>(id).isChecked
   }
 
-  private fun setPreferences() {
-    val preferences =
-      listOfNotNull(
-        PasswordOption.NoDigits.takeIf { !isChecked(R.id.numerals) },
-        PasswordOption.AtLeastOneSymbol.takeIf { isChecked(R.id.symbols) },
-        PasswordOption.NoUppercaseLetters.takeIf { !isChecked(R.id.uppercase) },
-        PasswordOption.NoAmbiguousCharacters.takeIf { !isChecked(R.id.ambiguous) },
-        PasswordOption.FullyRandom.takeIf { !isChecked(R.id.pronounceable) },
-        PasswordOption.NoLowercaseLetters.takeIf { !isChecked(R.id.lowercase) }
-      )
+  private fun getSelectedOptions(): List<PasswordOption> {
+    return listOfNotNull(
+      PasswordOption.NoDigits.takeIf { !isChecked(R.id.numerals) },
+      PasswordOption.AtLeastOneSymbol.takeIf { isChecked(R.id.symbols) },
+      PasswordOption.NoUppercaseLetters.takeIf { !isChecked(R.id.uppercase) },
+      PasswordOption.NoAmbiguousCharacters.takeIf { !isChecked(R.id.ambiguous) },
+      PasswordOption.FullyRandom.takeIf { !isChecked(R.id.pronounceable) },
+      PasswordOption.NoLowercaseLetters.takeIf { !isChecked(R.id.lowercase) }
+    )
+  }
+
+  private fun getLength(): Int {
     val lengthText = requireDialog().findViewById<EditText>(R.id.lengthNumber).text.toString()
-    val length = lengthText.toIntOrNull()?.takeIf { it >= 0 } ?: PasswordGenerator.DEFAULT_LENGTH
-    setPrefs(requireActivity().applicationContext, preferences, length)
+    return lengthText.toIntOrNull()?.takeIf { it >= 0 } ?: PasswordGenerator.DEFAULT_LENGTH
+  }
+
+  /**
+   * Enables the [PasswordOption]s in [options] and sets [targetLength] as the length for generated
+   * passwords.
+   */
+  private fun setPrefs(ctx: Context, options: List<PasswordOption>, targetLength: Int): Boolean {
+    ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE).edit {
+      for (possibleOption in PasswordOption.values()) putBoolean(
+        possibleOption.key,
+        possibleOption in options
+      )
+      putInt("length", targetLength)
+    }
+    return true
   }
 }
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/PasswordGenerator.kt b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/PasswordGenerator.kt
deleted file mode 100644
index bd21ea0a..00000000
--- a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/PasswordGenerator.kt
+++ /dev/null
@@ -1,138 +0,0 @@
-/*
- * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
- * SPDX-License-Identifier: GPL-3.0-only
- */
-package dev.msfjarvis.aps.util.pwgen
-
-import android.content.Context
-import androidx.core.content.edit
-import dev.msfjarvis.aps.R
-import dev.msfjarvis.aps.util.extensions.clearFlag
-import dev.msfjarvis.aps.util.extensions.hasFlag
-import dev.msfjarvis.aps.util.settings.PreferenceKeys
-
-enum class PasswordOption(val key: String) {
-  NoDigits("0"),
-  NoUppercaseLetters("A"),
-  NoAmbiguousCharacters("B"),
-  FullyRandom("s"),
-  AtLeastOneSymbol("y"),
-  NoLowercaseLetters("L")
-}
-
-object PasswordGenerator {
-
-  const val DEFAULT_LENGTH = 16
-
-  const val DIGITS = 0x0001
-  const val UPPERS = 0x0002
-  const val SYMBOLS = 0x0004
-  const val NO_AMBIGUOUS = 0x0008
-  const val LOWERS = 0x0020
-
-  const val DIGITS_STR = "0123456789"
-  const val UPPERS_STR = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-  const val LOWERS_STR = "abcdefghijklmnopqrstuvwxyz"
-  const val SYMBOLS_STR = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
-  const val AMBIGUOUS_STR = "B8G6I1l0OQDS5Z2"
-
-  /**
-   * Enables the [PasswordOption] s in [options] and sets [targetLength] as the length for generated
-   * passwords.
-   */
-  fun setPrefs(ctx: Context, options: List<PasswordOption>, targetLength: Int): Boolean {
-    ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE).edit {
-      for (possibleOption in PasswordOption.values()) putBoolean(
-        possibleOption.key,
-        possibleOption in options
-      )
-      putInt("length", targetLength)
-    }
-    return true
-  }
-
-  fun isValidPassword(password: String, pwFlags: Int): Boolean {
-    if (pwFlags hasFlag DIGITS && password.none { it in DIGITS_STR }) return false
-    if (pwFlags hasFlag UPPERS && password.none { it in UPPERS_STR }) return false
-    if (pwFlags hasFlag LOWERS && password.none { it in LOWERS_STR }) return false
-    if (pwFlags hasFlag SYMBOLS && password.none { it in SYMBOLS_STR }) return false
-    if (pwFlags hasFlag NO_AMBIGUOUS && password.any { it in AMBIGUOUS_STR }) return false
-    return true
-  }
-
-  /** Generates a password using the preferences set by [setPrefs]. */
-  @Throws(PasswordGeneratorException::class)
-  fun generate(ctx: Context): String {
-    val prefs = ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE)
-    var numCharacterCategories = 0
-
-    var phonemes = true
-    var pwgenFlags = DIGITS or UPPERS or LOWERS
-
-    for (option in PasswordOption.values()) {
-      if (prefs.getBoolean(option.key, false)) {
-        when (option) {
-          PasswordOption.NoDigits -> pwgenFlags = pwgenFlags.clearFlag(DIGITS)
-          PasswordOption.NoUppercaseLetters -> pwgenFlags = pwgenFlags.clearFlag(UPPERS)
-          PasswordOption.NoLowercaseLetters -> pwgenFlags = pwgenFlags.clearFlag(LOWERS)
-          PasswordOption.NoAmbiguousCharacters -> pwgenFlags = pwgenFlags or NO_AMBIGUOUS
-          PasswordOption.FullyRandom -> phonemes = false
-          PasswordOption.AtLeastOneSymbol -> {
-            numCharacterCategories++
-            pwgenFlags = pwgenFlags or SYMBOLS
-          }
-        }
-      } else {
-        // The No* options are false, so the respective character category will be included.
-        when (option) {
-          PasswordOption.NoDigits,
-          PasswordOption.NoUppercaseLetters,
-          PasswordOption.NoLowercaseLetters -> {
-            numCharacterCategories++
-          }
-          PasswordOption.NoAmbiguousCharacters,
-          PasswordOption.FullyRandom,
-          // Since AtLeastOneSymbol is not negated, it is counted in the if branch.
-          PasswordOption.AtLeastOneSymbol -> {}
-        }
-      }
-    }
-
-    val length = prefs.getInt(PreferenceKeys.LENGTH, DEFAULT_LENGTH)
-    if (pwgenFlags.clearFlag(NO_AMBIGUOUS) == 0) {
-      throw PasswordGeneratorException(ctx.resources.getString(R.string.pwgen_no_chars_error))
-    }
-    if (length < numCharacterCategories) {
-      throw PasswordGeneratorException(
-        ctx.resources.getString(R.string.pwgen_length_too_short_error)
-      )
-    }
-    if (!(pwgenFlags hasFlag UPPERS) && !(pwgenFlags hasFlag LOWERS)) {
-      phonemes = false
-      pwgenFlags = pwgenFlags.clearFlag(NO_AMBIGUOUS)
-    }
-    // Experiments show that phonemes may require more than 1000 iterations to generate a valid
-    // password if the length is not at least 6.
-    if (length < 6) {
-      phonemes = false
-    }
-
-    var password: String?
-    var iterations = 0
-    do {
-      if (iterations++ > 1000)
-        throw PasswordGeneratorException(
-          ctx.resources.getString(R.string.pwgen_max_iterations_exceeded)
-        )
-      password =
-        if (phonemes) {
-          RandomPhonemesGenerator.generate(length, pwgenFlags)
-        } else {
-          RandomPasswordGenerator.generate(length, pwgenFlags)
-        }
-    } while (password == null)
-    return password
-  }
-
-  class PasswordGeneratorException(string: String) : Exception(string)
-}
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomNumberGenerator.kt b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomNumberGenerator.kt
deleted file mode 100644
index 8ef490cc..00000000
--- a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomNumberGenerator.kt
+++ /dev/null
@@ -1,31 +0,0 @@
-/*
- * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
- * SPDX-License-Identifier: GPL-3.0-only
- */
-package dev.msfjarvis.aps.util.pwgen
-
-import java.security.SecureRandom
-
-private val secureRandom = SecureRandom()
-
-/** Returns a number between 0 (inclusive) and [exclusiveBound](exclusive). */
-fun secureRandomNumber(exclusiveBound: Int) = secureRandom.nextInt(exclusiveBound)
-
-/** Returns `true` and `false` with probablity 50% each. */
-fun secureRandomBoolean() = secureRandom.nextBoolean()
-
-/**
- * Returns `true` with probability [percentTrue]% and `false` with probability `(100 - [percentTrue]
- * )`%.
- */
-fun secureRandomBiasedBoolean(percentTrue: Int): Boolean {
-  require(1 <= percentTrue) { "Probability for returning `true` must be at least 1%" }
-  require(percentTrue <= 99) { "Probability for returning `true` must be at most 99%" }
-  return secureRandomNumber(100) < percentTrue
-}
-
-fun <T> Array<T>.secureRandomElement() = this[secureRandomNumber(size)]
-
-fun <T> List<T>.secureRandomElement() = this[secureRandomNumber(size)]
-
-fun String.secureRandomCharacter() = this[secureRandomNumber(length)]
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPasswordGenerator.kt b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPasswordGenerator.kt
deleted file mode 100644
index c1a8aeb1..00000000
--- a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPasswordGenerator.kt
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
- * SPDX-License-Identifier: GPL-3.0-only
- */
-package dev.msfjarvis.aps.util.pwgen
-
-import dev.msfjarvis.aps.util.extensions.hasFlag
-
-object RandomPasswordGenerator {
-
-  /**
-   * Generates a random password of length [targetLength], taking the following flags in [pwFlags]
-   * into account, or fails to do so and returns null:
-   *
-   * - [PasswordGenerator.DIGITS]: If set, the password will contain at least one digit; if not set,
-   * the password will not contain any digits.
-   * - [PasswordGenerator.UPPERS]: If set, the password will contain at least one uppercase letter;
-   * if not set, the password will not contain any uppercase letters.
-   * - [PasswordGenerator.LOWERS]: If set, the password will contain at least one lowercase letter;
-   * if not set, the password will not contain any lowercase letters.
-   * - [PasswordGenerator.SYMBOLS]: If set, the password will contain at least one symbol; if not
-   * set, the password will not contain any symbols.
-   * - [PasswordGenerator.NO_AMBIGUOUS]: If set, the password will not contain any ambiguous
-   * characters.
-   */
-  fun generate(targetLength: Int, pwFlags: Int): String? {
-    val bank =
-      listOfNotNull(
-          PasswordGenerator.DIGITS_STR.takeIf { pwFlags hasFlag PasswordGenerator.DIGITS },
-          PasswordGenerator.UPPERS_STR.takeIf { pwFlags hasFlag PasswordGenerator.UPPERS },
-          PasswordGenerator.LOWERS_STR.takeIf { pwFlags hasFlag PasswordGenerator.LOWERS },
-          PasswordGenerator.SYMBOLS_STR.takeIf { pwFlags hasFlag PasswordGenerator.SYMBOLS },
-        )
-        .joinToString("")
-
-    var password = ""
-    while (password.length < targetLength) {
-      val candidate = bank.secureRandomCharacter()
-      if (pwFlags hasFlag PasswordGenerator.NO_AMBIGUOUS &&
-          candidate in PasswordGenerator.AMBIGUOUS_STR
-      ) {
-        continue
-      }
-      password += candidate
-    }
-    return password.takeIf { PasswordGenerator.isValidPassword(it, pwFlags) }
-  }
-}
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPhonemesGenerator.kt b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPhonemesGenerator.kt
deleted file mode 100644
index 5a5f5f21..00000000
--- a/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPhonemesGenerator.kt
+++ /dev/null
@@ -1,180 +0,0 @@
-/*
- * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
- * SPDX-License-Identifier: GPL-3.0-only
- */
-package dev.msfjarvis.aps.util.pwgen
-
-import dev.msfjarvis.aps.util.extensions.hasFlag
-import java.util.Locale
-
-object RandomPhonemesGenerator {
-
-  private const val CONSONANT = 0x0001
-  private const val VOWEL = 0x0002
-  private const val DIPHTHONG = 0x0004
-  private const val NOT_FIRST = 0x0008
-
-  private val elements =
-    arrayOf(
-      Element("a", VOWEL),
-      Element("ae", VOWEL or DIPHTHONG),
-      Element("ah", VOWEL or DIPHTHONG),
-      Element("ai", VOWEL or DIPHTHONG),
-      Element("b", CONSONANT),
-      Element("c", CONSONANT),
-      Element("ch", CONSONANT or DIPHTHONG),
-      Element("d", CONSONANT),
-      Element("e", VOWEL),
-      Element("ee", VOWEL or DIPHTHONG),
-      Element("ei", VOWEL or DIPHTHONG),
-      Element("f", CONSONANT),
-      Element("g", CONSONANT),
-      Element("gh", CONSONANT or DIPHTHONG or NOT_FIRST),
-      Element("h", CONSONANT),
-      Element("i", VOWEL),
-      Element("ie", VOWEL or DIPHTHONG),
-      Element("j", CONSONANT),
-      Element("k", CONSONANT),
-      Element("l", CONSONANT),
-      Element("m", CONSONANT),
-      Element("n", CONSONANT),
-      Element("ng", CONSONANT or DIPHTHONG or NOT_FIRST),
-      Element("o", VOWEL),
-      Element("oh", VOWEL or DIPHTHONG),
-      Element("oo", VOWEL or DIPHTHONG),
-      Element("p", CONSONANT),
-      Element("ph", CONSONANT or DIPHTHONG),
-      Element("qu", CONSONANT or DIPHTHONG),
-      Element("r", CONSONANT),
-      Element("s", CONSONANT),
-      Element("sh", CONSONANT or DIPHTHONG),
-      Element("t", CONSONANT),
-      Element("th", CONSONANT or DIPHTHONG),
-      Element("u", VOWEL),
-      Element("v", CONSONANT),
-      Element("w", CONSONANT),
-      Element("x", CONSONANT),
-      Element("y", CONSONANT),
-      Element("z", CONSONANT)
-    )
-
-  private class Element(str: String, val flags: Int) {
-
-    val upperCase = str.uppercase(Locale.ROOT)
-    val lowerCase = str.lowercase(Locale.ROOT)
-    val length = str.length
-    val isAmbiguous = str.any { it in PasswordGenerator.AMBIGUOUS_STR }
-  }
-
-  /**
-   * Generates a random human-readable password of length [targetLength], taking the following flags
-   * in [pwFlags] into account, or fails to do so and returns null:
-   *
-   * - [PasswordGenerator.DIGITS]: If set, the password will contain at least one digit; if not set,
-   * the password will not contain any digits.
-   * - [PasswordGenerator.UPPERS]: If set, the password will contain at least one uppercase letter;
-   * if not set, the password will not contain any uppercase letters.
-   * - [PasswordGenerator.LOWERS]: If set, the password will contain at least one lowercase letter;
-   * if not set and [PasswordGenerator.UPPERS] is set, the password will not contain any lowercase
-   * characters; if both are not set, an exception is thrown.
-   * - [PasswordGenerator.SYMBOLS]: If set, the password will contain at least one symbol; if not
-   * set, the password will not contain any symbols.
-   * - [PasswordGenerator.NO_AMBIGUOUS]: If set, the password will not contain any ambiguous
-   * characters.
-   */
-  fun generate(targetLength: Int, pwFlags: Int): String? {
-    require(pwFlags hasFlag PasswordGenerator.UPPERS || pwFlags hasFlag PasswordGenerator.LOWERS)
-
-    var password = ""
-
-    var isStartOfPart = true
-    var nextBasicType = if (secureRandomBoolean()) VOWEL else CONSONANT
-    var previousFlags = 0
-
-    while (password.length < targetLength) {
-      // First part: Add a single letter or pronounceable pair of letters in varying case.
-
-      val candidate = elements.secureRandomElement()
-
-      // Reroll if the candidate does not fulfill the current requirements.
-      if (!candidate.flags.hasFlag(nextBasicType) ||
-          (isStartOfPart && candidate.flags hasFlag NOT_FIRST) ||
-          // Don't let a diphthong that starts with a vowel follow a vowel.
-          (previousFlags hasFlag VOWEL &&
-            candidate.flags hasFlag VOWEL &&
-            candidate.flags hasFlag DIPHTHONG) ||
-          // Don't add multi-character candidates if we would go over the targetLength.
-          (password.length + candidate.length > targetLength) ||
-          (pwFlags hasFlag PasswordGenerator.NO_AMBIGUOUS && candidate.isAmbiguous)
-      ) {
-        continue
-      }
-
-      // At this point the candidate could be appended to the password, but we still have
-      // to determine the case. If no upper case characters are required, we don't add
-      // any.
-      val useUpperIfBothCasesAllowed =
-        (isStartOfPart || candidate.flags hasFlag CONSONANT) && secureRandomBiasedBoolean(20)
-      password +=
-        if (pwFlags hasFlag PasswordGenerator.UPPERS &&
-            (!(pwFlags hasFlag PasswordGenerator.LOWERS) || useUpperIfBothCasesAllowed)
-        ) {
-          candidate.upperCase
-        } else {
-          candidate.lowerCase
-        }
-
-      // We ensured above that we will not go above the target length.
-      check(password.length <= targetLength)
-      if (password.length == targetLength) break
-
-      // Second part: Add digits and symbols with a certain probability (if requested) if
-      // they would not directly follow the first character in a pronounceable part.
-
-      if (!isStartOfPart &&
-          pwFlags hasFlag PasswordGenerator.DIGITS &&
-          secureRandomBiasedBoolean(30)
-      ) {
-        var randomDigit: Char
-        do {
-          randomDigit = secureRandomNumber(10).toString(10).first()
-        } while (pwFlags hasFlag PasswordGenerator.NO_AMBIGUOUS &&
-          randomDigit in PasswordGenerator.AMBIGUOUS_STR)
-
-        password += randomDigit
-        // Begin a new pronounceable part after every digit.
-        isStartOfPart = true
-        nextBasicType = if (secureRandomBoolean()) VOWEL else CONSONANT
-        previousFlags = 0
-        continue
-      }
-
-      if (!isStartOfPart &&
-          pwFlags hasFlag PasswordGenerator.SYMBOLS &&
-          secureRandomBiasedBoolean(20)
-      ) {
-        var randomSymbol: Char
-        do {
-          randomSymbol = PasswordGenerator.SYMBOLS_STR.secureRandomCharacter()
-        } while (pwFlags hasFlag PasswordGenerator.NO_AMBIGUOUS &&
-          randomSymbol in PasswordGenerator.AMBIGUOUS_STR)
-        password += randomSymbol
-        // Continue the password generation as if nothing was added.
-      }
-
-      // Third part: Determine the basic type of the next character depending on the letter
-      // we just added.
-      nextBasicType =
-        when {
-          candidate.flags.hasFlag(CONSONANT) -> VOWEL
-          previousFlags.hasFlag(VOWEL) ||
-            candidate.flags.hasFlag(DIPHTHONG) ||
-            secureRandomBiasedBoolean(60) -> CONSONANT
-          else -> VOWEL
-        }
-      previousFlags = candidate.flags
-      isStartOfPart = false
-    }
-    return password.takeIf { PasswordGenerator.isValidPassword(it, pwFlags) }
-  }
-}
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 7b476587..c11e6f25 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -391,5 +391,6 @@
   <string name="pgp_key_import_succeeded">Successfully imported PGP key</string>
   <string name="pgp_key_import_succeeded_message">The key ID of the imported key is given below, please review it for correctness:\n%1$s</string>
   <string name="pref_category_pgp_title">PGP settings</string>
+  <string name="pwgen_some_error_occurred">Some error occurred</string>
 
 </resources>