# Secure Aviation Control through a Streamlined ADS-B Perception System
## 3 Related Work
### Securing ADS-B
#### 3.2.1 Cryptography and Fingerprinting  
This subsection will discuss the solutions based on using cryptography and fingerprinting of the signals to provide a secure framework for ADS-B. There were different takes and efforts to try to secure ADS-B using cryptography. Initially, [PERSON] et al. [2] suggested that using public key cryptography and fingerprinting is the security measure \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ref.** & \multicolumn{2}{c}{**Approach**} & \multicolumn{2}{c}{**Contributions**} & \multicolumn{2}{c}{**Limitations**} \\ \hline
[13] — & Demonstrated a low-cost attack on ADS-B. & — & Showed the availability of low-cost attack setup. & — & The study suggested that no mitigation methods were used to avoid or deal with this attack. \\ \hline
[13] — & Low-cost jammer to interference with signals communicated within an ADS-B communication channel. & — & Able to deform the signals, either fully or partially. & — & No security measures were suggested. \\ \hline
[15] — & Interference attack by sending forged signals. & — & Achieved a fairly high error rate of 32.39\%. & — & They did not provide ways to intercept such signals from reaching aircraft. \\ \hline
[16] — & Transmitted multiple fake signals to flood communication channels. & — & ADS-B is weak in terms of security and prone to attacks. & — & No suggestions to improve ADS-B security. \\ \hline
[17] — & Autopilot responses to ghost aircraft injection. & — & Performed ghost aircraft injection attack. & — & This study suggested no security measures and only focused on the reactions of the autopilot. \\ \hline
[18] — & A drone simulator will be used to assess the reaction of 50 participants to injected messages. & — & Showed how pilots would react to spoofed data an attacker sends. The reactions yielded multiple perspectives, and they based the reactions on the nationalities of the participants. & — & More in-depth testing is required to show why pilots made certain decisions after receiving false information. \\ \hline
[19] — & Radiofrequency attacks on ADS-B messages. & — & A huge loss was reported after performing radio frequency attacks. & — & This study suggested no measures to make the collision avoidance system within an aircraft. \\ \hline  & & & & ADS-B is currently unreliable for full deployment. & — & It did not provide any suggestions on implying verification or validation methods into the ADS-B protocol or any security practices to enhance the security. \\ \hline
[20] — & Presented a new type of attack; teleporting ghost aircraft. & — & The ADS-B protocol lacks any verification or validation of the information. & — & This study suggested no measures to make the collision avoidance system prone to this attack. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Cont. that ADS-B needs to be dependable and trustworthy. Unfortunately, this would require protocol changes, making it costly, especially over time. [PERSON] et al. [21] proposed a detection model that detects malicious messages by fingerprinting wireless radio signals. Still, even though their proposed method is unfamiliar, only 50 percent of the malicious signals were detected. Additionally, [PERSON] et al. [22] improved on a previous framework by merging cryptography and timestamp validation, and even though it had huge value, it did not affect the ADS-B messages with any form of alteration that could cause any corruption. [PERSON] et al. [23] tried another method that combined the information of consecutive signals sent by the two antennas on an aircraft to detect attacks that used a single transmitter. On the other hand, the authors in [24] replaced the cyclic redundancy check found at the end of an ADS-B message with a HASH produced by HMAC. They made a compound of different messages in the same digest. They verified them together to have enough space to add the hash into the ADS-B messages to verify all of the messages when they were received. In another study, [PERSON] et al.