首次放到 git

utils/browser-random-bytes.js

@@ -0,0 +1,43 @@
+'use strict';
+
+var convert = require('./convert');
+var defineProperty = require('./properties').defineProperty;
+
+var crypto = global.crypto || global.msCrypto;
+if (!crypto || !crypto.getRandomValues) {
+
+    console.log('WARNING: Missing strong random number source; using weak randomBytes');
+
+    crypto = {
+        getRandomValues: function(buffer) {
+            for (var round = 0; round < 20; round++) {
+                for (var i = 0; i < buffer.length; i++) {
+                    if (round) {
+                        buffer[i] ^= parseInt(256 * Math.random());
+                    } else {
+                        buffer[i] = parseInt(256 * Math.random());
+                    }
+                }
+            }
+
+            return buffer;
+        },
+        _weakCrypto: true
+    };
+}
+
+function randomBytes(length) {
+    if (length <= 0 || length > 1024 || parseInt(length) != length) {
+        throw new Error('invalid length');
+    }
+
+    var result = new Uint8Array(length);
+    crypto.getRandomValues(result);
+    return convert.arrayify(result);
+};
+
+if (crypto._weakCrypto === true) {
+    defineProperty(randomBytes, '_weakCrypto', true);
+}
+
+module.exports = randomBytes;