Azin Azizifard - Department of Computer Engineering, Dezfoul Branch , Islamic Azad University, Dezfoul Iran
Mohamad Qermezkon - Department of Computer Engineering, Dezfoul Branch , Islamic Azad University, Dezfoul Iran
Tahereh Postizadeh - Department of Computer Engineering, Dezfoul Branch , Islamic Azad University, Dezfoul Iran
Hamid Barati - Department of Computer Engineering, Dezfoul Branch , Islamic Azad University, Dezfoul Iran

Today, optimal performance and cost advantages of using Internet telephonyare obvious. Despite current standardized techniques, voice transferring throughprotocol (VoIP) has lower security than traditional telephony. One of the mostimportant security issues which should be noticed in using VoIP is end -to-end user2identity, i.e. when there is a connection between user A and B, user A should beassured of the identity of user B, and vice versa. The authentication of identity is oneof so important information that could guarantee the security and integrity ofinformation [1]. In this study, the security of VoIP and data steganography throughthe protocol has been investigated. Finally, a technique for data steganography4over this protocol will be proposed using the method of Residue Number System3.Also, using the combination of RNS, DNA sequences, and Huffman compressingalgorithm, an algorithm is proposed for data steganography through VoIP. Thealgorithm improves security of the process of transmission of hidden text and canuse the bandwidth effectively.

Voice Over Internet Protocol, Steganography, Session Initiation Protocol (SIP), Residue Number System, DNAString, Huffman Algorithm