Quote from: Cred on June 09, 2014, 07:08:44 PM

After just reading on another thread about the difficulty of entered a high entropy private it seems that what is needed is a device that has no connectivity and whose purpose is only to sign transactions.

Is anyone working on something like this or is the idea flawed?

I am working on something like this. Its called sigsafe and it is an electronic key tag that signs bitcoin transactions over a non-exploitable air gap. The device is probably too simple to be considered a hardware wallet; instead, its more like a paper wallet that can produce ECDSA signatures. The device has both high-security applications such as implementing a cold/hot wallet system where the cold wallet can only send coins to the hot wallet, and low-security applications such as a tap and pay tag for purchasing retail items at PoS terminals. Because the device uses the NFC standard, it is highly interoperable with existing phones, laptops, PoS terminals, and other RFID readers. In fact, when HTML5 browsers begin to support the Web NFC API, it should be possible to create webpages that request signatures from the sigsafe to complete an online payment or to login to a website using the bitID protocol and a single tap.

Here's the project development thread: https://bitcointalk.org/index.php?topic=610453.0

And here's a rendering of the device: