Security Enhancement for Multicast over Internet of Things by Dynamically Constructed Fountain Codes

Algorithm 1

DC fountain-encoding procedures .

BS records the rowers for full-0-lines and full-1-lines of

matrix and respectively stores them in matrix and .

Determine whether the matrix is empty.

If is not empty

Encoding rules are as follows:

(a) Randomly choose one element from denoted as .

(b) Take out all elements from denoted as

(c) The encoded fountain packet is the exclusive-or of:

,

where denotes the encoded fountain packet

during -th slot.

else

Switch to Step .

Determine whether the length of is smaller than .

If length

Encoding rules follow Algorithm 2.

else

Encoding rules follow Algorithm 3.