# A Low-Complexity Security Scheme for Drone Communication Based on PUF and LDPC
## 3 Security Architecture
### Error Correction Schemes
#### 3.4.3 Decoding Algorithm Selection
## 4 Security Analysis

### Informal Security Analysis

In our model, considering the limited resources of drones, the drones are considered vulnerable to attacks, while the ground stations and databases are marked as difficult-to-attack objects (using widely recognized high-security-level authentication and encryption systems). Therefore, we only need to consider the security between the ground stations and drones, as well as that among the drones. According to the communication scheme of this study, the dynamic key between drones is distributed by the GS after authorization and the dynamic secret key is iterated by calculating the hash value, and only needs to synchronize the link state (packet loss rate) with each other during the negotiation process and are fully encrypted throughout. Therefore, the security of drone communication is determined based on the security at the time of takeoff authorization. The information that can be known in an open channel is shown in Table 3. A comparison of security with other protocols is shown in Table 6.

1. Resistance of replay attack: All messages transmitted in the channel have timestamps added that cannot be tampered with. 2. Resistance of man-in-the-middle (MITM) attack: All the information of the whole group network is encrypted. Except for the group network information, which is broadcasted, all the information is encrypted using the P2P secret key assigned by the GS, and the keys are dynamic and do not need to be negotiated in the channel so that no third party can eavesdrop. Thus, an intermediary is not be able to interfere with the authentication process. 3. Mutual authentication: The GS judges the legality of the drone based on whether or not the drone correctly decodes the \(ID_{\delta}\). The drone judges the legality of the GS based on comparing the \(ID_{\delta}\) with the power-up response \(ID\), and since the number of erroneous bits added by the GS is not large, the \(ID\) should have a similarity to the \(ID_{\delta}\) higher than 98.8% (see Figure 6 for the ECC performance of this paper). 4. Resistance of impersonation attack: The protocol in this paper is based on PUFs and requires the GS to bootstrap the extraction of PUFs. Therefore, an attacker cannot obtain PUF information and cannot impersonate a drone. In addition, this paper assumes that the security of the GS is authenticated by the database and supervised by the administrator, so the GS cannot be spoofed by default. 5. Resistance of DoS attack: An attacker who wants to block the authentication process needs to obtain the static key of the drone (obtaining the key requires capturing the drone). However, the static secret key is unique for each drone, so it is not reasonable to use the static secret key to attack the drone. The protocol in this paper is semi-automated and requires an administrator to assign drones. The GS does not initiate authentication on a missing drone; then, the static key obtained by the attacker is invalid. 6. Resistance of physical capture attack: Because all encryption information at the drone end is provided by the ground station during authorization and the ROM only stores the static key, if the static key is obtained by reverse engineering the assembly instructions stored in the program memory, using this key in a conventional attack can only obtain half of the challenge from the ground station and the drone's response. Since the fingerprint PUF is not available, the challenge given by the drone is not available, nor is the information about the identity PUF. In addition, once the captured drone loses power, all authentication information is lost. * Provision of forward and backward secrecy: The proposed protocol authentication process includes a challenge of fingerprint PUF, fingerprint, extracted information of identity PUF, ID with noise, and parity with noise.