BitSIM is a thin, flexible card that can be stuck on any existing SIM card as an add-on hardware layer. BitSIM converts the SIM card into a fully encrypted bitcoin wallet compatible with a wide range of cell phones, including cheap and unsophisticated feature phones.
“BitSIM puts bitcoins on any SIM, on any mobile phone, for mass adoption and frictionless ecosystem uptake,” claims the BitSIM website. Users will be able to pay locally with NFC-enabled phones, but also send and receive bitcoin with a simple SMS to other users anywhere in the world.
The BitSIM website notes that this simple application can disrupt the $1 trillion remittance market, which is poorly served by companies such as Western Union.
BitSIM seems tailor-made for sending remittances to developing regions of the world where the adoption of cell phones is booming, but most users have only cheap-feature phones. And remittances are just the first application: The BitSIM technology could add a simple bitcoin payment layer to the Internet of Things (IoT), the upcoming pervasive network of smart, connected devices.
BitSIM, based in Hong Kong, is funded by Seedcoin, a seed-stage Bitcoin and blockchain startup virtual incubator.
In a video interview titled “BitSIM: Bitcoin Between SIM and Phone,” the startup’s founder, Leon Gerard Vandenberg, shows how, by slipping a zero-footprint SIM between the carrier’s SIM card and the phone, BitSIM “up-techs even ancient feature-phones with a new technology stack.” Providing NFC and fully-encrypted Bitcoin transactions over SMS, even a smart-contract-capable JVM runtime, BitSIM is “a stealthy technology injection that routes around the carrier monopolies without their permission.”
An interesting feature of the BitSIM add-on sticker is that it doesn’t require the authorization of the phone manufacturer, or of the carrier that provides the SIM.
“The hardware is called a ZSIM,” explains Vandenberg. “It’s a zero-footprint SIM that sits between the original SIM and the carrier’s cell phone and interposes SIM commands between the original SIM and the phone. So the phone thinks there is a SIM there, and the original SIM thinks there is a phone there.” (See this trending discussion on Reddit for explanations of how the BitSIM technology works.)
BitSIM’s ZSIM is a “thin SIM” (also known as “overlay SIM”), a chip embedded into a thin plastic sheet that sits on top of an ordinary SIM card, making available to the user services that were not foreseen by the carrier or the phone maker. Thin SIMs have been denounced as a security risk by phone carriers, but that is likely due to their potential to disrupt the carriers’ business models more than to an actual risk for consumers.
In a September 2014 interview with Brave New Coin, Vandenberg noted that, with the globally adopted use of SMS technology, BitSIM can literally bank the unbanked overnight by giving power back to users, effectively allowing anybody with a cell phone to be their own bank. “Anything running on top of the Bitcoin protocol is also within the reach of bitSIM users,” he said, and noted that bitSIM is a platform supported by a developer community.