Generated wallet addresses do not seem random in MyEtherWallet

Question

I have generated a couple (well, dozens) of accounts with MyEtherWallet (currently v3.5.6), and strangely every single one of them starts with "0xff...".

I remember doing the same experiment in an older version and getting completely (well, seemingly more) random addresses. But now the first two digits are always F. I tried changing the password too. Did something change in the algorithm? Is this a bug?

Answer 1

It looks like this is an intentional choice by MEW: the relevant code is here.

while (true) {
   var privKey = ethUtil.crypto.randomBytes(32)
   if (ethUtil.privateToAddress(privKey)[0] === 0xFF) {
       return new Wallet(privKey)
    }
}

It's essentially generating a vanity address: it generates addresses until the first byte is ff.

The commit: https://github.com/kvhnuke/etherwallet/commit/119d741ba3d154d46ffeaab886ca324b3b257644