## Security Analysis
### Traceable  
Figure 11 shows the characteristics of the blockchain structure. Any event message received by \(SCC\) automatically chains the message with the sender's signatures to the blockchain. The chaining flow is shown as follows:  
1. In the event trigger phase, once the event is triggered from the \(\mathit{IMC}\) in the client's house, the \(SCC\) receives the message and sends \((R_{\mathit{IMC}_{1}},h_{\mathit{IMC}_{1}},Si_{\mathit{IMC}_{1}},Si_{\mathit{ SIMC}_{2}},M_{\mathit{Event}_{1}})\) to the \(BCC\), then the \(BCC\) calculates the hash with the message, and creates that information as the first block.
2. Next, the \(SCC\) sends \((R_{SCC_{2}},h_{SCC_{2}},Si_{SSCC_{3}},Si_{SSCC_{4}},M_{\mathit{Event}_{2}})\) to the \(BCC\), then the \(BCC\) calculates the hash value of the first block and chains that information as the second block.
3. In the task allocation phase, the \(SCC\) sends \((R_{SCC_{3}},h_{SCC_{3}},Si_{SSCC_{3}},Si_{SSCC_{4}},M_{\mathit{Event}_{3}})\) to the \(BCC\), then the \(BCC\) calculates the hash value with the message and hash value in the second block and chains that information as the third block.  
Continuously, when any event message needs to chain to the \(BCC\), the \(SCC\) needs to send the parameters, the signatures, and the message from the sender, then calculate the current block's hash value with the message and the previous block's hash value. Therefore, the processing of the event can be recorded in detail and can be traced.  
The phase of creating the blockchain with signatures is defined as follows:  
Figure 11: The event message chaining process in the blockchain.  
1. Event-trigger phase The message from the _IMC_ in the client's house is: \[Sig_{IMC_{1}}=1-{r_{3}}^{-1}\cdot{Prk_{IMC}}\cdot H(M_{Event_{1}})\text{mod}p\] (106) \[Sig_{IMC_{2}}=M_{Event_{1}}+{Prk_{IMC}}\text{mod}p\] (107) SCC's staff confirm received the message from the _IMC_: \[Sig_{SCC_{3}}=1-{r_{4}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{2}})\text{mod}p\] (108) \[Sig_{SCC_{4}}=M_{Event_{2}}+{Prk_{SCC}}\text{mod}p\] (109) 2. Task allocating phase The messages are sent to the _SG_: \[Sig_{SCC_{5}}=1-{r_{5}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{3}})\text{mod}p\] (110) \[Sig_{SCC_{6}}=M_{Event_{3}}+{Prk_{SCC}}\text{mod}p\] (111) The message from the _SG_ is: \[Sig_{SCC_{1}}=1-{r_{6}}^{-1}\cdot{Prk_{SC}}\cdot H(M_{Event_{4}})\text{mod}p\] (112) \[Sig_{SG_{2}}=M_{Event_{4}}+{Prk_{SG}}\text{mod}p\] (113) SCC's staff confirm received the messages from the _SG_: \[Sig_{SCC_{7}}=1-{r_{7}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{5}})\text{mod}p\] (114) \[Sig_{SCC_{8}}=M_{Event_{5}}+{Prk_{SCC}}\text{mod}p\] (115) 3. Task accomplished phase The message from the _SG_ is: \[Sig_{SCC_{9}}=1-{r_{9}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{6}})\text{mod}p\] (116) \[Sig_{SCC_{4}}=M_{Event_{6}}+{Prk_{SG}}\text{mod}p\] (117) The messages are sent to the _C_: \[Sig_{SCC_{9}}=1-{r_{9}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{7}})\text{mod}p\] (118) \[Sig_{SCC_{10}}=M_{Event_{7}}+{Prk_{SCC}}\text{mod}p\] (119) The message from the \(C\) is: \[Sig_{SCC_{1}}=1-{r_{10}}^{-1}\cdot{Prk_{C}}\cdot H(M_{Event_{8}})\text{mod}p\] (120) \[Sig_{C_{2}}=M_{Event_{8}}+{Prk_{C}}\text{mod}p\] (121) SCC's staff confirm the received messages from the _C_: \[Sig_{SCC_{11}}=1-{r_{11}}^{-1}\cdot{Prk_{SCC}}\cdot H(M_{Event_{9}})\text{ mod}p\] (122) \[Sig_{SCC_{12}}=M_{Event_{9}}+{Prk_{SCC}}\text{mod}p\] (123) Therefore, the accessing party can easily track and verify the transactions via the blockchain.