Slipsteg

Slipsteg, short for SLIP steganography, is a class of covert communication techniques that hide information within SLIP-framed network traffic. The approach leverages the Serial Line Internet Protocol (SLIP), historically used to encapsulate IP packets over serial connections. In slipsteg, secret data is encoded into elements of the SLIP stream that are either ignored by ordinary processing or interpreted only by a cooperating endpoint.

Techniques in slipsteg fall mainly into two categories: payload-based and timing-based. Payload-based methods encode bits into the data portion of SLIP frames by using neutral or reserved regions, or by exploiting peculiarities of certain SLIP variants. Timing-based methods convey information by modulating the spacing or delays between consecutive SLIP frames. The effectiveness of these methods depends on the specific SLIP implementation, the network path, and the presence of processing devices that might alter or discard unusual framing.

Applications and limitations. Slipsteg is primarily discussed in the context of information security research and covert-channel studies. It illustrates how protocol design choices can enable hidden communication channels within seemingly simple systems. In practice, slipsteg faces challenges such as susceptibility to noise, packet loss, and interference from middleboxes or network appliances, which can degrade reliability and raise detectability concerns. As a result, it is typically explored as a controlled, scholarly concept rather than a broadly deployed technique.

See also. Covert channels, steganography, network security, traffic analysis.