TheArchive/session-android
1
0
Fork 0
mirror of https://github.com/oxen-io/session-android.git synced 2025-02-19 20:08:27 +00:00
Code Issues Packages Projects Releases Wiki Activity

Move MnemonicCodec to core

Browse Source
This commit is contained in:
Niels Andriesse 2019-05-29 15:17:19 +10:00
parent 289cc42a9e
commit a8caa4afc5
5 changed files with 0 additions and 141 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
assets/mnemonic/english.txt
View File

File diff suppressed because one or more lines are too long

1
assets/mnemonic/japanese.txt
View File

File diff suppressed because one or more lines are too long

1
assets/mnemonic/portuguese.txt
View File

File diff suppressed because one or more lines are too long

1
assets/mnemonic/spanish.txt
View File

File diff suppressed because one or more lines are too long

137
src/org/thoughtcrime/securesms/loki/Mnemonic.kt
View File

@ -1,137 +0,0 @@
package org.thoughtcrime.securesms.loki
import android.content.Context
import java.util.zip.CRC32
class MnemonicCodec(val context: Context) {
class Language(val context: Context, val configuration: Configuration) {
data class Configuration(val filename: String, val prefixLength: Int) {
companion object {
val english = Configuration("english", 3)
val japanese = Configuration("japanese", 3)
val portuguese = Configuration("portuguese", 4)
val spanish = Configuration("spanish", 4)
}
}
companion object {
val wordSetCache = mutableMapOf<Language, List<String>>()
val truncatedWordSetCache = mutableMapOf<Language, List<String>>()
}
fun loadWordSet(): List<String> {
val cachedResult = wordSetCache[this]
return if (cachedResult != null) {
cachedResult
} else {
val contents = context.assets.open(configuration.filename + ".txt").bufferedReader().readLine()
val result = contents.split(",")
wordSetCache[this] = result
result
}
}
fun loadTruncatedWordSet(): List<String> {
val cachedResult = wordSetCache[this]
return if (cachedResult != null) {
cachedResult
} else {
val prefixLength = configuration.prefixLength
val result = loadWordSet().map { it.substring(0 until prefixLength) }
truncatedWordSetCache[this] = result
result
}
}
}
sealed class DecodingError(val description: String) : Error() {
object Generic : DecodingError("Something went wrong. Please check your mnemonic and try again.")
object InputTooShort : DecodingError("Looks like you didn't enter enough words. Please check your mnemonic and try again.")
object MissingLastWord : DecodingError("You seem to be missing the last word of your mnemonic. Please check what you entered and try again.")
object InvalidWord : DecodingError("There appears to be an invalid word in your mnemonic. Please check what you entered and try again.")
object VerificationFailed : DecodingError("Your mnemonic couldn't be verified. Please check what you entered and try again.")
}
fun encode(hexEncodedString: String, languageConfiguration: Language.Configuration = Language.Configuration.english): String {
var string = hexEncodedString
val language = Language(context, languageConfiguration)
val wordSet = language.loadWordSet()
val prefixLength = languageConfiguration.prefixLength
val result = mutableListOf<String>()
val n = wordSet.size
val characterCount = string.length
for (chunkStartIndex in 0 until characterCount step 2) {
val chunkEndIndex = chunkStartIndex + 8
val p1 = string.substring(0 until chunkStartIndex)
val p2 = swap(string.substring(chunkStartIndex until chunkEndIndex))
val p3 = string.substring(chunkEndIndex until characterCount)
string = p1 + p2 + p3
}
for (chunkStartIndex in 0 until characterCount step 2) {
val chunkEndIndex = chunkStartIndex + 8
val x = string.substring(chunkStartIndex until chunkEndIndex).toInt(16)
val w1 = x % n
val w2 = ((x / n) + w1) % n
val w3 = (((x / n) / n) + w2) % n
result += listOf ( wordSet[w1], wordSet[w2], wordSet[w3] )
}
val checksumIndex = determineChecksumIndex(result, prefixLength)
val checksumWord = result[checksumIndex]
result.add(checksumWord)
return result.joinToString(" ")
}
fun decode(mnemonic: String, languageConfiguration: Language.Configuration = Language.Configuration.english): String {
val words = mnemonic.split(" ").toMutableList()
val language = Language(context, languageConfiguration)
val truncatedWordSet = language.loadTruncatedWordSet()
val prefixLength = languageConfiguration.prefixLength
var result = ""
val n = truncatedWordSet.size
// Check preconditions
if (words.size < 12) { throw DecodingError.InputTooShort }
if (words.size % 3 != 0) { throw DecodingError.MissingLastWord }
// Get checksum word
val checksumWord = words.removeAt(words.lastIndex)
// Decode
for (chunkStartIndex in 0 until words.size step 3) {
try {
val w1 = truncatedWordSet.indexOf(words[chunkStartIndex].substring(0 until prefixLength))
val w2 = truncatedWordSet.indexOf(words[chunkStartIndex + 1].substring(0 until prefixLength))
val w3 = truncatedWordSet.indexOf(words[chunkStartIndex + 2].substring(0 until prefixLength))
val x = w1 + n * ((n - w1 + w2) % n) + n * n * ((n - w2 + w3) % n)
if (x % n != w1) { throw DecodingError.Generic }
val string = "0000000" + x.toString(16)
result += swap(string.substring(string.lastIndex - 8 until string.lastIndex))
} catch (e: Exception) {
throw DecodingError.InvalidWord
}
}
// Verify checksum
val checksumIndex = determineChecksumIndex(words, prefixLength)
val expectedChecksumWord = words[checksumIndex]
if (expectedChecksumWord.substring(0 until prefixLength) != checksumWord.substring(0 until prefixLength)) { throw DecodingError.VerificationFailed }
// Return
return result
}
private fun swap(x: String): String {
val p1 = x.substring(6 until 8)
val p2 = x.substring(4 until 6)
val p3 = x.substring(2 until 4)
val p4 = x.substring(0 until 2)
return p1 + p2 + p3 + p4
}
private fun determineChecksumIndex(x: List<String>, prefixLength: Int): Int {
val bytes = x.joinToString { it.substring(0 until prefixLength) }.toByteArray()
val crc32 = CRC32()
crc32.update(bytes)
val checksum = crc32.value
return checksum.toInt() % x.size
}
}