ASN.1 and eUICC

Changing your Mobile Network Operator (MNO), even doing so temporarily while travelling internationally, required you to replace your SIM with a new one. In today’s world where everything can be done remotely using online services, it is unreasonable to require a user to go to a store to obtain a new SIM card or wait for days for one to be delivered.

The Embedded Universal Integrated Circuit Card (eUICC) is an embedded SIM card. It differs from an ordinary (replaceable) SIM card in that it’s built into mobile, M2M, and IoT devices and cannot be replaced. When such a device is produced it already contains a smart SIM card (eUICC), containing no information specific to an MNO or an individual user.

With eUICC, there is no need to manually install and replace MNO specific SIM cards. Preparing an eUICC for use is called provisioning and entails downloading a certain MNO specific file, called a profile, to the eUICC. The profile is a data structure specified in ASN.1 and encoded in ASN.1 DER (Distinguished Encoding Rules). Its format is specified in the eUICC Profile Package: Interoperable Format Technical Specification from the SIMAlliance. ASN.1, an international standard supporting features such as compact binary encodings, interoperability, and platform independence, is a perfect choice for the format of eUICC profile.

eUICC vendors can use OSS’ ASN-1Step to manually create eUICC profiles. They would receive provisioning information for a set of devices from a carrier, enter the information in the Value Editor of ASN-1Step, and encode to DER in order to create one or more eUICC profiles which can be transferred to the eUICC of target devices. Profiles can also be viewed or modified using ASN-1Step.

A Remote Provisioning System (RSP) allows for remote provisioning of the eUICC with a Mobile Network Operator (MNO) profile. The RSP also enables the secure, dynamic changing of profiles.

The OSS ASN.1 Tools can be used on the network elements of Remote Provisioning Systems to create and parse profiles. Various interfaces of the RSP nodes exchange profiles (encoded in ASN.1 DER), for example, the interface ES9+ between the SM-DP+ (Subscription Manager Data Preparation) and the LPD (Local Profile Download), and the interface ES11 between the LDS (Local Discovery Service) and the SM-DS (Subscription Manager Discovery Service). These interfaces can be implemented using the OSS ASN.1 Tools. The ASN.1 specification used by the RSPs is found in the GSMA RSP Technical Specification document. The specification is passed to the ASN.1 compiler to generate programming language specific structures or classes. The compiler generated code along with the high performance OSS ASN.1 runtime libraries are used to create applications for use on the RSP nodes to create and parse profiles.

Visit this link for more information about the OSS ASN.1 products and to download a trial. Online documentation for the ASN.1 products can be accessed here. If you have any questions about using the OSS ASN.1 products in eUICC applications, please contact info@oss.com.