diff options
Diffstat (limited to 'app/src/main/java/dev/msfjarvis/aps/util/pwgen')
4 files changed, 386 insertions, 0 deletions
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 new file mode 100644 index 00000000..ae26c7e3 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/PasswordGenerator.kt @@ -0,0 +1,139 @@ +/* + * Copyright © 2014-2020 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.settings.PreferenceKeys +import dev.msfjarvis.aps.util.extensions.clearFlag +import dev.msfjarvis.aps.util.extensions.hasFlag + +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 new file mode 100644 index 00000000..aae8d987 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomNumberGenerator.kt @@ -0,0 +1,33 @@ +/* + * Copyright © 2014-2020 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 new file mode 100644 index 00000000..f6341087 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPasswordGenerator.kt @@ -0,0 +1,45 @@ +/* + * Copyright © 2014-2020 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 new file mode 100644 index 00000000..408974d5 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/pwgen/RandomPhonemesGenerator.kt @@ -0,0 +1,169 @@ +/* + * Copyright © 2014-2020 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.toUpperCase(Locale.ROOT) + val lowerCase = str.toLowerCase(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) } + } +} |