Regarding [this concatSig method](https://github.com/MetaMask/metamask-plugin/blob/master/app/scripts/lib/idStore.js#L517), noted by @denisgranha padding zeros concatenating it in this way if some of the values or r/s is less than 64 bytes we have a problem with the final string
Regarding this concatSig method, noted by @denisgranha
padding zeros
concatenating it in this way
if some of the values or r/s is less than 64 bytes
we have a problem with the final string