Historically, SIM Operating Systems contained minimal functionality and memory for simple applications such as contact details and SMS storage. However, as telecommunication technology rapidly progresses, so has the once humble SIM card.

New market entrants such as MVNOs have begun working closely with SIM manufacturers in order to create additional value-added services through SIM applets. 

But what are SIM applets? How do they add value for your business? We provide insights on this and more.  

Java card technology

Before diving headfirst into SIM applets, we must first introduce Java Card.

Java Card technology adapts the Java platform for use on smart cards and other devices with highly specialized environments. These are environments where memory and processing constraints are more severe than those of Java ME devices.  

Within telecommunications, Java Card technology primarily targets embedded devices such as the eSIM and iSIM. The technology also extends to Smart Cards such credit and debit cards, NFC mobile payment and IDs including passports.

The Java Card technology specification consists of three parts: 

1. Virtual Machine (VM) specification: defines a subset of the Java programming language and a VM
2. Runtime Environment specification: defines the runtime behavior
3. API specification: defines the core framework and extension Java packages and classes for applications 

Compiling the code results in a .cap file which can be loaded onto the SIM or IMSI profile. This can be at point of manufacture or uploaded remotely Over-The-Air (OTA).  

Essentially, Java Card offers a secure, interoperable execution platform to store and update applications on a resource-constrained device known as secure elements. It also allows users to program the devices and make them application specific. All without compromising on the highest security standards. 

In fact, the minimum system requirement to run Java Card is 16 kilobytes of read-only memory (ROM), 8 kilobytes of EEPROM, and 256 bytes of RAM. 

Java card + SIM = SIM applets   

Now that we’ve briefly delved into Java Card technology briefly, how does it fit into the SIM picture?

Java Card programs that run on an eUICC enabled SIM is a SIM applet. Multiple applets from different vendors can coexist securely within the SIM. Each dedicated to fulfilling a specific task.

SIM applets are a way for service providers to build features independent from standard MNO offerings. In an IoT context, applets can be useful for Quality of Service (QoS) testing, encryption, blockchain applications and more. 

The increasing demand and new use cases has also motivated the demand for different SIM applets. They are also highly customizable for the rapidly evolving IoT landscape.

SIM applets & the ZARIOT ecosystem 

At ZARIOT we have established an ecosystem of partners to create bespoke, yet highly secure applets. These can be easily integrated to produce tangible benefits. Here are some examples: 

With atsign’s IoT Trust solution, data retains its full integrity with full end-to-end encryption. Data sharing is also controlled by the data owner, meaning it can only be viewed and used with authorisation. 

IoT Trust saves on hardware investments as it can be retrofitted to any IoT device equipped with an eUICC SIM. It also reduces administrative costs by eliminating the need to administer IPs and VPNs while facilitating regulatory compliance such as GDPR and industry specific criteria like HIPPA. 

Wadaro’s SIMGEO and SIM QoS solutions provides a more granular “device eye view” of performance compared to the usual network perspective. Allowing the proactive validation of service availability and performance.  

This helps to streamline monitoring and troubleshooting by minimizing the need for engineers to physically attend to the deployment site. Overall reducing downtime and accelerating fault resolution. 

SmartAxiom applies embedded blockchain on ZARIOT SIMs to leverage an established tamper-proof root of trust for unrivalled security, attestation, and connectivity.

The protectionism and provenance offered enables the secure sharing of information while decreasing risk and compliance costs.

If you’d like to learn more about our customized SIM applets, our partners or our solutions, schedule a one-one-one meeting with us today. Otherwise, read more about our partnerships by clicking on the links above, or why wait? Try our SIMs today.