废话不多述,封装完毕上代码
// It would take more than 10^12 years to brute-force a 128 bit seed using $1B worth of computing equipment.
public static final int DEFAULT_SEED_ENTROPY_BITS = 128;
public static final int DEFAULT_SEED_ENTROPY_BITS_15 = 160;
public synchronized boolean generateRandomSeed(final Context ctx, int size, String passphrase) {
String languageCode = Locale.getDefault().getLanguage();
Log.d("chendy", "default languageCode:" + languageCode);//zh
List<String> wordList = Bip39Reader.getBip39Words(ctx, "zh-Hans");
if (wordList.size() != Bip39Reader.WORD_LIST_SIZE) {
BRReportsManager.reportBug(new IllegalArgumentException("the list is wrong, size: " + wordList.size()), true);
return false;
}
int entropyBits=DEFAULT_SEED_ENTROPY_BITS;
if(size==Bip39Reader.WORD_DIGIT_CAPACITY_15){
entropyBits=DEFAULT_SEED_ENTROPY_BITS_15;
}
SecureRandom sr = new SecureRandom();
byte[] randomSeed = sr.generateSeed(size);
if (randomSeed.length != size)
throw new NullPointerException("failed to create the seed, seed length is not " +entropyBits+":"+ randomSeed.length);
List<String> mnemonicCode ;
if(false){
DeterministicSeed seed = new DeterministicSeed(sr,entropyBits,passphrase);
mnemonicCode = seed.getMnemonicCode();
Log.d("chendy", "a MnemonicCode:" + mnemonicCode);//zh
}else{
//或者用这个接口,复用前面的只产生了9个单词
randomSeed = BRCoreMasterPubKey.getEntropy(new SecureRandom(),entropyBits);
try {
mnemonicCode = BRCoreMasterPubKey.toMnemonic(wordList,randomSeed);
Log.d("chendy", "b MnemonicCode" );//zh
} catch (MnemonicException.MnemonicLengthException e) {
// cannot happen
throw new RuntimeException(e);
}
}
String mnemonic = org.bitcoinj.core.Utils.SPACE_JOINER.join(mnemonicCode);
Log.d("chendy", size+"位:" + mnemonic);//zh
if (mnemonicCode == null || mnemonicCode.size() == 0) {
BRReportsManager.reportBug(new NullPointerException("failed to encodeSeed"), true);
return false;
}
if (mnemonicCode.size() != size) {
BRReportsManager.reportBug(new NullPointerException("phrase does not have " +size+ " words:" +mnemonicCode.size() + ", lang: " + languageCode), true);
return false;
}
return true;
}
/**
* Convert entropy data to mnemonic word list.
*/
public static List<String> toMnemonic(List<String> wordList, byte[] entropy) throws MnemonicException.MnemonicLengthException {
if (entropy.length % 4 > 0)
throw new MnemonicException.MnemonicLengthException("Entropy length not multiple of 32 bits.");
if (entropy.length == 0)
throw new MnemonicException.MnemonicLengthException("Entropy is empty.");
// We take initial entropy of ENT bits and compute its
// checksum by taking first ENT / 32 bits of its SHA256 hash.
byte[] hash = Sha256Hash.hash(entropy);
boolean[] hashBits = bytesToBits(hash);
boolean[] entropyBits = bytesToBits(entropy);
int checksumLengthBits = entropyBits.length / 32;
Log.d("chendy","checksumLengthBits:"+checksumLengthBits);
// We append these bits to the end of the initial entropy.
boolean[] concatBits = new boolean[entropyBits.length + checksumLengthBits];
System.arraycopy(entropyBits, 0, concatBits, 0, entropyBits.length);
System.arraycopy(hashBits, 0, concatBits, entropyBits.length, checksumLengthBits);
// Next we take these concatenated bits and split them into
// groups of 11 bits. Each group encodes number from 0-2047
// which is a position in a wordlist. We convert numbers into
// words and use joined words as mnemonic sentence.
ArrayList<String> words = new ArrayList<>();
int nwords = concatBits.length / 11;
Log.d("chendy","nwords:"+nwords);
for (int i = 0; i < nwords; ++i) {
int index = 0;
for (int j = 0; j < 11; ++j) {
index <<= 1;
if (concatBits[(i * 11) + j])
index |= 0x1;
}
words.add(wordList.get(index));
}
return words;
}
private static boolean[] bytesToBits(byte[] data) {
boolean[] bits = new boolean[data.length * 8];
for (int i = 0; i < data.length; ++i)
for (int j = 0; j < 8; ++j)
bits[(i * 8) + j] = (data[i] & (1 << (7 - j))) != 0;
return bits;
}
public static byte[] getEntropy(SecureRandom random, int bits) {
checkArgument(bits <= MAX_SEED_ENTROPY_BITS, "requested entropy size too large");
//先产生一个16位随机字节数-->
byte[] seed = new byte[bits / 8];
random.nextBytes(seed);
return seed;
}