This year, a brand new integrated chip called the eSIM is set to replace the SIM card. We take a look at the technology behind this new feature
The SIM (Subscriber Identity Module) card has stood up to a number of transformations over the years. It was first introduced in the early 90s, together with GSM mobile communications. Since then, its physical form has changed and shrunk continuously over the years, but its core function and code that is stored inside it has remained the same. Every mobile or smartphone user requires a SIM card in order to be able to establish a connection with his or her provider’s network. Without a SIM card, the only thing that works is the emergency call feature. If the customer signs a contract with different proviers, they will get a different SIM for each provider.
There are also devices with multiple SIM slots (dual-SIM). The customer can use this function to log onto another wireless network when he is abroad. In some cases, telcos also offer a multi-SIM facility: This involves the presence of multiple SIMs within the framework of a single contract, so that the customer will be able to connect to the network using a mobile phone, a tablet or a smart watch.
An eSIM In Every Mobile Device
The dual-SIM and multi-SIM constructs show that the SIM card does not belong to an era in which everything is networked and the devices are always becoming smaller and thinner. In this case, the SIM slot is the only problem. Companies that produce hardware for internet of things have already responded.
This group includes suppliers for the automobile sector such as Infineon, which produce special chips. In addition to facilitating the communications involving the individual components in the car, these chips also play the role of a SIM by establishing a connection with the networks. Cars need robustly soldered chips, not sensitive SIM cards. Such an embedded SIM (or eSIM) is being produced in the well-established SON-8 designs.
All the big players in the mobile communications industry – from network providers like Deutsche Telekom to device manufacturers such as Samsung and Apple – want to pull the eSIM out of the mechanical world and integrate it into the daily routine of their mobile communication customers. The Groupe Speciale Mobile Association (GSMA) is currently developing a standard whose final version is supposed to be targeted at the market. In the future, all mobile devices are supposed to be connected to the network providers via the eSIM as the SIM slot is supposed to be removed completely from new mobile phones and tablets.
Instead, a chip will be integrated into the circuit board of the device. Since the eSIM is firmly embedded, it must be programmable: If the owner of the mobile phone switches over to a new provider, his new access data is written onto the chip, and the data associated with the previous provider is deactivated. The eSIM can also save data associated with multiple providers, which means that it can practically replace the dual-SIM facility. At the same time, each eSIM device can be activated for a specific user; this means that the multi-SIM construct will finally become part of our daily routine. From the customer’s point of view, this will translate to a smaller degree of effort and a larger measure of flexibility, in case he wishes to rapidly switch over to a new telco provider.
Telco Data Over The Web
But first, the industry has to set a standard and set up a new infrastructure, in order to ensure that the transfer of data onto the eSIM is protected. This process begins with the production of the eSIM, whereby two data sets are pre-installed: The first one contains information regarding a discovery server on the internet, which facilitates the first contact procedure, while the other one stores certificates.
The eSIM can use these certificates to check whether the data really is coming from the discovery server, and to authenticate itself over the server. If a customer buys the smartphone with the eSIM and signs a contract with a telco, it should provide him with a code, which the customer enters into his smartphone. The eSIM then makes contact with the discovery server and sends the code that the customer received when he signed the contract.
Discovery Servers To Process eSIM
On the other hand, the telco creates a profile for the eSIM after the contract has been signed. He sends this profile to a special service (subscription manager data preparation), which combines the profile with the appropriate certificate. Once the discovery server receives the code from the eSIM, it contacts the service and asks for the provider package. It then transfers and saves the profile (along with the certificate for the eSIM), and activates it. The owner of the mobile phone is now registered as a customer in the provider’s network.
The eSIM can also save multiple provider profiles, but only one is activated at any given time.
The discovery server represents the central point of the distribution system. Only the discovery server is allowed to create, activate or delete the provider profiles on the eSIM. Neither the customer nor the network operator can access it.
The GSMA has not yet decided who is to be allowed to offer the discovery servers. SIM producers such as Gemalto and providers such as T-Mobile in the USA already have a corresponding infrastructure for their eSIM ranges. Since discovery servers are allowed to programme eSIMs over the internet, a robust encryption system is necessary.
The GSMA has specified minimum requirements for the certificate-based authentication procedure and the connection establishment. The specified key sizes are practically unbreakable. The smartphones are the only things that are missing: The eSIMequipped iPhone 7 is expected to be launched in September.