**What did the increasing use of Machine to Machine (M2M) applications drive the need for?**
The increasing use of Machine to Machine (M2M) applications drove the need for *embedded and inaccessible SIM cards within the device.*
**What does the term eSIM refer to as defined by GSMA?**
As defined by GSMA, the term eSIM refers to:
> "The explicit functionality of the operating system to store multiple MNO profiles and perform remote provisioning and management of the profiles after they're issued."
**What are the two things GSMA selected to ensure that eSIM technology would not compromise mobile network security standards?**
The two things GSMA selected to ensure that eSIM technology would not compromise mobile network security standards are:
1. Global Platform (GP) card management standards.
2. State-of-the-art algorithms (ECC, AES).
**Is every non-removable SIM an eSIM?**
*No*, not every non-removable SIM is an eSIM.
> **What does and doesn't define eSIM?**
> *Functionality* defines eSIM. *Form factor* doesn't define eSIM.
**What is the key to access a cellular network regardless of SIM type?**
Regardless of SIM type, *the MNO / operator profile* is the key to access a cellular network.
**What has been the core functionality of the operator profile since the inception of the first digital mobile standard?**
Since the inception of the first digital mobile standard, the core functionality of the operator profile has been *the storage of subscriber credentials and the implementation of algorithms used for network access authentication.*
**What are the three components an operator profile must contain at least?**
The three components an operator profile must contain at least are:
1. A Mobile Network Operator Security Domain (MNO-SD).
2. A Network Access Application (NAA).
3. A file system.
> **What does the Mobile Network Operator Security Domain (MNO-SD) do?**
> The Mobile Network Operator Security Domain (MNO-SD) *manages the applications in the operator profile on behalf of the profile issuer (the MNO).*
> > **What is the Mobile Network Operator Security Domain (MNO-SD) equivalent to on regular SIMs?**
> > The Mobile Network Operator Security Domain (MNO-SD) is equivalent to *the Issuer Security Domain (ISD)* on regular SIMs.
>
> **What does the Network Access Application (NAA) do?**
> The Network Access Application (NAA) is *an application such as SIM, USIM, and ISIM which is selected by the device in order to access the related mobile network.*
>
> **What does the file system of an operator profile contain?**
> The File System of an operator profile contains:
> 1. Data files (Elementary Files or EF) that store subscriber network information.
> 2. Directory files (Dedicated Files or DF / ADF / MF) that allow functional grouping of files.
>
> **What can further be a part of an operator profile depending on the requirements of the operator?**
> Depending on the requirements of the operator, an operator profile can further have *more applications and Supplemental Security Domains (SSDs).*
**What is central to the security architecture of eSIM?**
The *Security Domain (SD)* is central to the security architecture of eSIM.
> **What is a Security Domain (SD)?**
> A Security Domain (SD) is a special application which has:
> * Key material.
> * Algorithms for cryptographic operations.
> * Specific privileges managing the card's applications.
>
> > **What are the two things a Security Domain (SD) provides?**
> > The two things a Security Domain (SD) provides are:
> > 1. A trusted security level for the authentication of system entities.
> > 2. The protection of the integrity and confidentiality of the communication.
**What are the three Security Domains (SDs) defined for eSIM?**
The three Security Domains (SDs) defined for eSIM are:
1. Issuer Security Domain Root (ISD-R).
2. Issuer Security Domain Profile (ISD-P).
3. eUICC Controlling Authority Security Domain (ECASD).
> **What does the Issuer Security Domain Root (ISD-R) do?**
> The Issuer Security Domain Root (ISD-R) *performs eSIM management functions on ISD-Ps.*
>
> **What does the Issuer Security Domain Profile (ISD-P) do?**
> The Issuer Security Domain Profile (ISD-P) *hosts a unique profile.*
>
> **What does the eUICC Controlling Authority Security Domain (ECASD) do?** [(1)](https://www.gsma.com/newsroom/wp-content/uploads/SGP_05_v1_1.pdf)
> The eUICC Controlling Authority Security Domain (ECASD) *provides services to the ISD-Rs and ISD-Ps in order to perform confidential key establishments.*
>
> **What are the two types of Security Domains which are installed and personalized by the eUICC Manufacturer (EUM)?**
> The two types of Security Domains which are installed and personalized by the eUICC Manufacturer (EUM) are:
> 1. The ISD-R.
> 2. The ECASD.
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