Concealment of Information in Inactive Audio Frames of VoIP

-Steganography is the hiding of a secret message within an ordinary message and the extraction of secret message at its destination. In digital steganography, electronic communications may include steganographic coding inside of a transport layer, such as a document file, image file, program or protocol. This paper describes how to segregate the audio that are streaming in the Voice over Internet Protocol (VoIP) and a steganography algorithm for embedding data in the inactive frames of low bit rate audio streams.VoIP is an IP telephony term for a set of facilities used to manage the delivery of voice information over the Internet. Voice activity detection (VAD), is a technique used in speech processing in which the presence or absence of human speech is detected. The main uses of VAD are in speech coding and speech recognition, it can avoid unnecessary coding/transmission of silence packets in Voice over Internet Protocol applications, saving on computation and on network bandwidth. This VAD algorithm decides whether the current audio frame is an active voice or inactive voice. The experimental results show the VAD process. The purpose of segregating the audio frames is to embed the data in audio frame. These audio frames are encoded with G.723.1 source codec.