eSIM Technical Guide
Architecture, standards, and practical implementation for European travelers.
eSIM Architecture
The eSIM ecosystem is built on a layered architecture defined by GSMA RSP specifications. The eUICC (embedded Universal Integrated Circuit Card) is a tamper-resistant secure element containing a Java Card operating system. It stores operator profiles - packages of authentication keys, network credentials, and service parameters.
The LPA (Local Profile Assistant) is the software layer managing profile downloads and providing the user interface. It mediates between the eUICC and external provisioning servers.
GSMA Standards
| Spec | Scope | Version |
|---|---|---|
| SGP.22 | Consumer devices | v3.0 (2023) |
| SGP.02 | M2M/IoT | v4.2 (2020) |
| SGP.21 | Consumer architecture | v3.0 (2023) |
Remote SIM Provisioning
RSP is the process by which operator profiles are securely delivered to eUICC chips. The SM-DP+ server prepares and stores encrypted profiles. The SM-DS (Discovery Service) helps devices find available profiles.
QR code decoded by LPA - SM-DP+ address extracted
eUICC presents certificate to SM-DP+ for authentication
Encrypted profile package downloaded to device
eUICC decrypts and installs profile in secure storage
Device registers on carrier network
Activation
iPhone: Settings - Cellular - Add Cellular Plan - scan QR. Android: Settings - Network - SIM Management - Add eSIM - scan QR. Activate before departure over Wi-Fi for best results.
European Coverage
Europe has excellent eSIM support. All major countries have 4G LTE coverage exceeding 97% of population. 5G is available in major cities. Most regional eSIM plans use roaming partnerships with local operators.
Security Architecture
eSIM profiles are cryptographically bound to specific eUICC chips using PKI certificates. Private keys never leave the secure element. This makes unauthorized profile transfer significantly harder than physical SIM swapping.