The capacity of a packet length covert channel

Covert channels are used for information hiding and realize one of the most serious security threat. Widespread IP networks allow for designing such channels on the basis of special properties of packet data transfer. Packet length covert channels are resistant to traffic encryption, but some difficulties to detect them are known. It makes significant an investigation of capacity limitation methods. This work presents a technique to estimate and limit the capacity of the covert channels based on the packet length modulation by traffic padding.