# The eIDAS Regulation: A Survey of Technological Trends for European Electronic Identity Schemes
## 9 Lessons Learned
### Security Considerations  
Based on our analysis in Section 3, 90% of eID means under analysis support either LoA substantial and/or high. This implies that these eID means to protect the service by demanding two authentication factors, which makes it difficult for an attacker to use someone else eID means. To provide a general comparison among the various technologies adopted by each eID means per LoA regarding the security level and resistance against different types of attackers, we leverage the MuFASA [61] tool. This tool aims to assist normal users and security experts--during the design phase of Multi-Factor Authentication (MFA) protocols--by providing a high-level report regarding possible risks associated with the specified MFA protocol and its resistance to a set of attacker models. Note that the tool supports a subset of attacker models defined in [8], namely: Device Thief (DT), Authenticator Duplicator (AD), Eavesdropping Software (ES), Shoulder Surfer (SS), Social Engineer (SE), Man in the Browser (MB), and Man in the Mobile (MM). The interested reader can refer to the NIST specification [8] and MuFASA document for the definition of the attacker models. In the following, we highlight some of the interesting findings by analyzing the eID means using MuFASA (Interested readers can refer to our companion website for checking the reports generated by MuFASA, regarding the security analysis of the solution). * All the eID means, independently of their adopted authentication factors, are not resistant against the (extremely powerful) MB attacker model;
* 12 eID means use PWD, which is the least secure authenticator and exposes these solutions to ES, SE, MB, and SS attacker models. However, it is worth mentioning that all the 12 eID means offer an additional authentication mechanism that provides a higher LoA, which can be used when necessary;
* Concerning the eID means with LoA S, the eID means that are using PWD + QR (1 eID mean) and/or PWD + PN (4 eID means) are more secure in comparison with the eID means that are using other authenticator types for LoA S (reported in Table 2). The main reasons are: (i) the number of successful attackers with higher risk is less than the other methods, and (ii) these methods are not susceptible to the ES attacker model, while this is not the case for the other available authenticator types for LoA S;
* Concerning the eID means with LoA S that are using PWD + SW and/or PWD + HW (13 eID means), the security of their solution can increase according to the features of the OTP generation provided by the SW/HW. In the case that the generation of OTP output is uniquely associated with the ongoing operation--dynamic linking [62]--the solution would be more secure in comparison to the one that does not consider dynamic linking. The main reason for the improvement of the security is related to the fact that: (i) the generated OTP is unique for that specific operation, and (ii) at the time of the operation, the identity of the demandant is displayed to the user and the user has to explicitly agree on the ongoing operation to generate the OTP;
* Concerning the eID means with LoA S that are adopting QR as an authenticator (10 eID means), the mobile app protection mechanism can affect the security level of the solution. Based on the results of our analysis using MuFASA, the usage of the fingerprint can improve the security w.r.t. the usage of PIN. In the following, we provide specific security considerations for the eID means using QR and/or PWD + SMS within their solutions. The QR authentication factor must be used with caution as this method is vulnerable to phishing attacks, as explained by the authors in [63; 64]. It is worth mentioning that some measures can be considered by the eID means to reduce such kinds of attack, namely [54]: (i) the eID means app can show the origin of the request (e.g., the domain where the response will be sent) and/or ask the user to confirm this origin.