/// <summary>
/// Obtains the word list for a given language for mnemonic phrases, or if it does not exist,
/// creates one from the given words.
/// </summary>
/// <param name="language">The language of the word list to obtain.</param>
/// <param name="words">The array of words to use to create the word list if one was not already parsed.</param>
/// <returns>Returns a word list for the given language, used for mnemonic phrases.</returns>
public static WordList GetWordList(WordListLanguage language, string[] words)
{
// Try to get our word list
bool success = _cachedWordLists.TryGetValue(language, out WordList result);
if (success)
{
return(result);
}
// If we couldn't get it, parse a new one
WordList wordList = new WordList(language, words);
// Set it in our lookup
_cachedWordLists[language] = wordList;
// Return our word list.
return(wordList);
}
/// <summary>
/// Obtains the word list for a given language for mnemonic phrases, or if it does not exist,
/// reads one from the given filename.
/// </summary>
/// <param name="language">The language of the word list to obtain.</param>
/// <param name="fileName">The filename of the word list to read from if one was not already parsed.</param>
/// <returns>Returns a word list for the given language, used for mnemonic phrases.</returns>
public static WordList GetWordList(WordListLanguage language, string fileName)
{
// Try to get our word list
bool success = _cachedWordLists.TryGetValue(language, out WordList result);
if (success)
{
return(result);
}
// If we couldn't get it, parse a new one
string allText = File.ReadAllText(fileName);
WordList wordList = new WordList(language, allText);
// Set it in our lookup
_cachedWordLists[language] = wordList;
// Return our word list.
return(wordList);
}
/// <summary>
/// Initializes a mnemonic phrase from the given mnemonic string.
/// </summary>
/// <param name="mnemonic">The mnemonic string to initialize this mnemonic phrase from, for key derivation.</param>
public MnemonicPhrase(string mnemonic)
{
// If our argument is null, we throw an exception, otherwise we set our mnemonic string.
MnemonicString = mnemonic.Trim() ?? throw new ArgumentException("Provided mnemonic string was null or empty.");
// Determine the word list (language) the mnemonic string belongs to by checking indicies.
WordList = WordList.GetWordList(MnemonicString);
// Obtain our words from our mnemonic.
MnemonicWords = WordList.SplitMnemonic(MnemonicString);
// Verify our word count is valid
if (MnemonicWords.Length < MNEMONIC_WORDS_MINIMUM || MnemonicWords.Length > MNEMONIC_WORDS_MAXIMUM)
{
throw new ArgumentException($"Provided entropy data of this size would represent {MnemonicWords.Length} words. Should be between {MNEMONIC_WORDS_MINIMUM}-{MNEMONIC_WORDS_MAXIMUM} (inclusive).");
}
// Initialize our indices array.
Indices = new int[MnemonicWords.Length];
// Loop for each index we want to resolve for the words in our mnemonics
for (int i = 0; i < Indices.Length; i++)
{
// Determine the word index for the indexed word.
int currentWordIndex = WordList.GetWordIndex(MnemonicWords[i]);
// If the index is invalid, throw an exception.
if (currentWordIndex < 0)
{
throw new ArgumentException($"Could not resolve word \"{MnemonicWords[i]}\" in word list for language \"{WordList.Language}\".");
}
// Set the word index.
Indices[i] = currentWordIndex;
}
}
/// <summary>
/// Obtains the word list for a given language for mnemonic phrases, or if it does not exist,
/// parses one from the embedded word list resources in this assembly.
/// </summary>
/// <param name="language">The language of the word list to obtain.</param>
/// <returns>Returns a word list for the given language, used for mnemonic phrases.</returns>
public static WordList GetWordList(WordListLanguage language)
{
lock (_cachedWordLists)
{
// Try to get our word list
bool success = _cachedWordLists.TryGetValue(language, out WordList result);
if (success)
{
return(result);
}
// Obtain the appropriate word list from our resource files.
Assembly currentAssembly = Assembly.GetExecutingAssembly();
string resourceName = null;
switch (language)
{
case WordListLanguage.Chinese_Simplified:
resourceName = "wordlist_chinese_simplified.txt";
break;
case WordListLanguage.Chinese_Traditional:
resourceName = "wordlist_chinese_traditional.txt";
break;
case WordListLanguage.English:
resourceName = "wordlist_english.txt";
break;
case WordListLanguage.French:
resourceName = "wordlist_french.txt";
break;
case WordListLanguage.Italian:
resourceName = "wordlist_italian.txt";
break;
case WordListLanguage.Japanese:
resourceName = "wordlist_japanese.txt";
break;
case WordListLanguage.Korean:
resourceName = "wordlist_korean.txt";
break;
case WordListLanguage.Spanish:
resourceName = "wordlist_spanish.txt";
break;
}
// If our resource name is null, throw an exception
if (resourceName == null)
{
throw new ArgumentException($"Could not obtain an embedded word list for language \"{resourceName}\".");
}
// Obtain our full resource name (it should end with the resource filename).
resourceName = currentAssembly.GetManifestResourceNames().First(x =>
{
int targetIndex = x.Length - resourceName.Length;
if (targetIndex < 0)
{
return(false);
}
return(x.LastIndexOf(resourceName, StringComparison.OrdinalIgnoreCase) == targetIndex);
});
// Open a stream on the resource
Stream stream = currentAssembly.GetManifestResourceStream(resourceName);
// Read all the text from the stream.
StreamReader streamReader = new StreamReader(stream);
string allText = streamReader.ReadToEnd();
streamReader.Close();
stream.Close();
// Create a word list instance
WordList wordList = new WordList(language, allText);
// Set it in our cached word lists
_cachedWordLists[language] = wordList;
// Return our word list
return(wordList);
}
}
/// <summary>
/// Initializes a mnemonic phrase for the given language, with the optionally given entropy data (or newly generated data if none is provided).
/// </summary>
/// <param name="wordListLanguage">The language to create a mnemonic phrase in.</param>
/// <param name="entropy">The optionally given entropy data to generate a mnemonic phrase from. If null, generates new entropy data of the maximum size.</param>
public MnemonicPhrase(WordListLanguage wordListLanguage, byte[] entropy = null)
{
// Set our word list
WordList = WordList.GetWordList(wordListLanguage);
// If our entropy is null, initialize a new set.
if (entropy == null)
{
// Create a buffer of random bytes (entropy) using our RNG.
int maximumEntropySize = (MNEMONIC_ENTROPY_BITS_PER_CHECKSUM_BIT * (MNEMONIC_WORDS_MAXIMUM / MNEMONIC_WORDS_PER_CHECKSUM_BIT)) / 8;
entropy = new byte[maximumEntropySize];
_random.GetBytes(entropy);
}
// Verify our entropy size is divisible by the range of a checksum.
int entropySizeBits = (entropy.Length * 8);
if (entropySizeBits % MNEMONIC_ENTROPY_BITS_PER_CHECKSUM_BIT != 0)
{
throw new ArgumentException($"Provided entropy data must be divisible by {MNEMONIC_ENTROPY_BITS_PER_CHECKSUM_BIT}");
}
// Calculate our component sizes.
int checksumBitcount = entropySizeBits / MNEMONIC_ENTROPY_BITS_PER_CHECKSUM_BIT;
int wordCount = checksumBitcount * MNEMONIC_WORDS_PER_CHECKSUM_BIT;
// Verify our word count is valid
if (wordCount < MNEMONIC_WORDS_MINIMUM || wordCount > MNEMONIC_WORDS_MAXIMUM)
{
throw new ArgumentException($"Provided entropy data of this size would represent {wordCount} words. Should be between {MNEMONIC_WORDS_MINIMUM}-{MNEMONIC_WORDS_MAXIMUM} (inclusive).");
}
// Calculate our SHA256 hash of the entropy.
byte[] checksum = sha256Provider.ComputeHash(entropy);
// Now we write the entropy followed by the checksum bits (which we will use to interpret a mnemonic from later).
BitStream bitStream = new BitStream();
bitStream.WriteBytes(entropy);
bitStream.WriteBytes(checksum, checksumBitcount);
// Move back to the start of the data
bitStream.Position = 0;
bitStream.BitPosition = 0;
// Read every word index, which are represented by 11-bit unsigned integers. At the same time, we resolve our mnemonic words.
int wordIndexCount = (int)(bitStream.BitLength / MNEMONIC_WORD_INDEX_BITCOUNT);
Indices = new int[wordIndexCount];
MnemonicWords = new string[Indices.Length];
for (int i = 0; i < Indices.Length; i++)
{
Indices[i] = (int)bitStream.ReadUInt64(MNEMONIC_WORD_INDEX_BITCOUNT);
MnemonicWords[i] = WordList.Words[Indices[i]];
}
// Close the bitstream.
bitStream.Close();
// Join all strings into a mnemonic sentence.
MnemonicString = WordList.JoinMnemonic(MnemonicWords);
}
