Manually create entropy for better performance

Way faster than brute forcing randomly generated seeds

package.json

@@ -5,6 +5,7 @@
   "author": "Luke Childs <lukechilds123@gmail.com>",
   "license": "MIT",
   "dependencies": {
-    "bip39": "^2.5.0"
+    "bip39": "^2.5.0",
+    "randombytes": "^2.0.6"
   }
 }

src/index.js

@@ -1,13 +1,42 @@
+const randomBytes = require('randombytes');
 const bip39 = require('bip39');
 
-const dogeSeed = (entropy = 128) => {
-    const dogeModifiers = ["so", "such", "many", "much", "very"];
-    while (true) {
-        const mnemonic = bip39.generateMnemonic(entropy).split(' ');
-        if(dogeModifiers.includes(mnemonic[0]) && dogeModifiers.includes(mnemonic[2]) && mnemonic[0] !== mnemonic[2]) {
-            return mnemonic.join(' ');
-        }
-    }
+const MUCH = '10010001000';
+const SUCH = '11011000011';
+const VERY = '11110010111';
+
+const bytesToBinary = buffer => buffer
+  .toString('hex')
+  .match(/.{2}/g)
+  .map(byte => parseInt(byte, 16).toString(2).padStart(8, '0'))
+  .join('');
+
+const binaryToBytes = binaryString => Buffer.from(
+  binaryString
+    .match(/(.{1,8})/g)
+    .map(binary => parseInt(binary, 2))
+);
+
+const randomNumberBetween = (min, max) => Math.floor(parseInt(randomBytes(1).toString('hex'), 16) / 256 * (max - min + 1) + min);
+
+const dogeSeed = (strength = 128) => {
+  const entropy = randomBytes(strength / 8);
+  const words = bytesToBinary(entropy).match(/.{1,11}/g);
+
+  const dogeModifiers = [
+    MUCH,
+    SUCH,
+    VERY
+  ];
+
+  const index = randomNumberBetween(0, dogeModifiers.length - 1);
+  words[0] = dogeModifiers[index];
+  dogeModifiers.splice(index, 1);
+  words[2] = dogeModifiers[randomNumberBetween(0, dogeModifiers.length - 1)];
+
+  const dogefiedEntropy = binaryToBytes(words.join(''));
+
+  return bip39.entropyToMnemonic(dogefiedEntropy);
 };
 
 module.exports = dogeSeed;

yarn.lock

@@ -77,7 +77,7 @@ pbkdf2@^3.0.9:
     safe-buffer "^5.0.1"
     sha.js "^2.4.8"
 
-randombytes@^2.0.1:
+randombytes@^2.0.1, randombytes@^2.0.6:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/randombytes/-/randombytes-2.0.6.tgz#d302c522948588848a8d300c932b44c24231da80"
   integrity sha512-CIQ5OFxf4Jou6uOKe9t1AOgqpeU5fd70A8NPdHSGeYXqXsPe6peOwI0cUl88RWZ6sP1vPMV3avd/R6cZ5/sP1A==