VoNR-IPD: A Novel Timing-Based Network Steganography for Industrial Internet

Table 1

The main notations and symbols.

Notation	Description
Nor-IPDs	The normal VoNR IPDs
Syn-IPDs	The synchronization IPDs
Steg-IPDs	The steganographic IPDs
	The jittered normal VoNR IPDs
	The main distribution of VoNR jitter
	The IPD interval with larger probability
	The IPD interval with smaller probability
	The mapping interval of IPDs to secret bit “0” or “1”
,	The upper or lower limit of the corresponding IPD interval
	The ith secret bit of industrial data
	The ith steganographic IPD
	The ith normal VoNR IPD
M	The steganographic embedding mode
	The interval of embedding sdi into di
	The mapping interval of IPDs to embedding mode
,	The upper or lower limit of the corresponding IPD interval
md	The generated synchronization IPD
,	The intensity factor of antinoise