Selective Encryption Algorithm Implementation for Video Call on Skype Client Alwi Alfiansyah Ramdan 1 , Rinaldi Munir 2 1 Informatics Engineering, Bandung Institute of Technology 2 Informatics Research Group, Bandung Institute of Technology Jl. Ganeca 10, Bandung, Indonesia 1 alfiansyah.ramdan@gmail.com 2 rinaldi-m@stei.itb.ac.id Abstract—Video calling is one of the widely used method of communicating. Encryption is applied to video call data to keep it secret. Real-time encryption is needed to support real-time communication such as video calling. Selective encryption is present as a solution to this problem. Skype is software that supports video calling. It cannot be ascertained whether Skype communication channel can be eavesdropped or not, since Skype communication protocol is very closed and concealed. Because of skype closed and concealed communication protocol, there is possibility that Skype party can eavesdrop communication in its communication channel. In this paper, we proposed a Skype client application made especially for video calling. Its main objective is to implement a selective encryption algorithm in video calling, especially via Skype. This Skype client is implemented in C++ programming language using Skypekit API from Skype. Testing proved that Skype client built support video calling with minor delay. Selective encryption algorithm is implemented to encrypt video in this Skype client. Keywords— selective encryption, Skype client, video call. I. INTRODUCTION Information is a primary needs in this era. Information can be obtained through communication. Video call is technology that is used as a medium of communication. Video calling enables two or more parties to communicate face to face even though the distance between the communicant is huge [8] . With this video call technology, distance and time problems in communication can be solved. However, there is another problem: the problem of security. This problem of security includes issues of confidentiality and the rights of access to information. There must be a mechanism that can be trusted to maintain the confidentiality of such information. The trick is to encrypt the sent information [4] . The standard encryption algorithm continues to grow. Currently, the standard encryption algorithm is AES [5] . In the use of video call, the encryption performed must support sending and receiving video call data quickly, so it does not interfere with the video call itself that is expected to occur in real-time (or close to) [7] . Selective encryption algorithm is algorithm that can support this real-time encryption. Selective encryption algorithm is a technique to encrypt compressed data file by simply doing the encryption on some part of data file and left the rest without encrypted [1] . Some examples of selective encryption algorithms are Real- time Video Encryption Algorithm (RVEA), Chaos-based Video Encryption Algorithm (CbVEA) and AEGIS. RVEA encrypts only the sign bits of I-Frames [3] . CbVEA encrypts only certain parts in accordance with the chaotic map [7] . AEGIS encrypt only the I-Frames and sequence header containing all encoding initialization parameters [9] . Skype is one example of software that supports video call. Skype is a software that allows users to communicate with each other using video chat, voice chat, or text chat via internet [6] . Skype claims that they have secured communication channel with encryption. The encryption used is RSA for key exchange, and Advanced Encryption Standard (AES) to encrypt transmitted information [14] . However, these secured channels’ presence cannot be ascertained where and when. It happens because Skype hide and conceal their system including their communication protocol from outsiders [6] . Because of this sealed Skype systems and obscurity of encryption used by Skype, there is possibility that Skype party can eavesdrop communication in its communication channels. Moreover, the Skype party cannot guarantee whether the Skype party can eavesdrop the communication in their communication channels or not [14] . In this paper, we present an implementation of selective encryption algorithm for video call on Skype client. We did some experiments to measure the processing time required to perform encryption/decryption process. II. MPEG-4 AVC/H.264 H.264/Advance Video Coding (AVC) is a method and format of video compression standard used by the industry from MPEG family. One important reason for the use of H.264/AVC as a standard and widespread use by the industry is the increased performance of H.264 than the previous video compression standard, MPEG-2. H.264 offers much better video compression performance than MPEG-2. H.264 allows video compression to produce much less number of bits than using MPEG-2 for the same picture quality and resolution on the video. Thus, there will be more video elements that can be stored or transmitted using H.264 format [13] . Jurnal Sarjana Institut Teknologi Bandung bidang Teknik Elektro dan Informatika Vol. 1, No. 2 Juli 2012