Algorithm 2: Simplified Fountain Code Encoder (SFCEA)

Input: P: byte array of shellcode, l: slice size (in bytes), s: encryption seed Output: Encoded packet $(I,C)$ where I: slice indices; C: encoded data 1 Step 1: Encrypt the shellcode: 2 $P_a\leftarrow P_a\oplus s,\forall a\in \{0,1,\dots ,|P|-1\}$; 3 Step 2: Calculate the number of slices: 4 $X\leftarrow \lceil \left|P\right|/l\rceil$; 5 Step 3: Randomly select the degree: 6 $d\in [1,X]$; 7 Step 4: Initialize the packet data: 8 $C\leftarrow {\left\{0\right\}}^l$; 9 Step 5: Randomly choose d indices: 10 $I\subseteq \{0,1,\dots ,X-1\}$; 17 Step 7: Return the encoded packet: $(I,C)$;