Application of Digital Forensics to Identify Human Voices Using the System Development Life Cycle (SDLC) Method

Published Online February 2022 in MECS                                  and Computer Science

• 1.    Introduction

• 2.    Related Works

The development of multimedia technology has made it easy to produce sound recordings. An example is the features and applications on cellphones that can make it easy to perform various types of recordings, either in the form of telephone conversations or other personal recordings. This convenience on the one hand will help efforts to collect digital evidence. Therefore, it is not surprising that various cases handled by law enforcers at this time have involved voice recordings as an important piece of evidence for investigations and various case disclosures. In this case, a common problem faced in cases involving recorded evidence is how to ensure the originality of the voice of the perpetrator which is the key in case investigation and disclosure. Based on data from the [1]National Police-Criminal Investigation Unit, namely January-October the National Police in Indonesia handled 1,763 cybercrime cases. From this figure, the police have at least completed 835 cybercrime cases. In this data, the highest cybercrime is fraud. To tackle cyber cases besides security management which aims to prevent cyber cases, handling procedures are also needed if the incident has already occurred and has resulted in a violation of the law, where one of the procedures carried out is digital forensics.

The number of audio forensic frameworks and investigative guidance documents that are currently developing has not provided an answer to the need for a standard framework for audio forensic investigations. As research conducted by Zjalic, (2017) p.55, proposes a framework for the audio forensic enhancement process, the framework consists of 4 main stages with 18 sub- stages that can be done in the audio forensic enhancement process [2], then Huizen, et al (2016) ) p.2., which developed an audio forensic acquisition technique framework and produced 7 stages, namely

Based on the SDLC explanation, there is a problem in this research, how is the application of Digital Forensics for Digital Audio identification using the Systems Development Life Cycle (SDLC) method, with the aim that the application of Digital Forensics for Digital Audio identification uses the Systems Development Life Cycle (SDLC) method. Audio identification for audio forensic investigations, with the human voice identification framework that will be developed, this framework can make it easy for investigators to carry out investigations related to audio evidence, as a reference for further research related to the same research studies related to development. human voice identification framework and audio forensic investigation techniques.

Several studies have been conducted previously became a reference in this research, including the Application of a System Development Life Cycle (SDLC) in Developing an Audio Forensic Framework, [9]. In this study, the analysis technique used is pictorial statistical analysis, formant analysis, and spectrogram analysis on three audio recording analyzes without manipulation of audio objects.

• [10], Malukan research related to the evidentiary process efforts to support audio originality or the similarity of audio sources of evidence with suspects by using the pitch concept approach, statistical formant and bandwidth analysis, graphical distribution, and spectrograms.

In another study conducted by [11], this method has characteristics that can record the history of input, so it can be assumed that the method can see the previous digital forensic investigation framework (DFIF) sequence to form a new DFIF. Where this is meant is combining 6 types of frameworks and eliminating the same stages into one new framework with the sequential logic method.

• [12], basic empathy steps in contacting Audio forensics. The goal is to combine four types of frameworks with the sequential Logic method.

• 3.    Material and Method

  Systems Development Life Cycle (SDLC) or the system development life cycle is basically a model and methodology that can be used to develop an existing system. According to [13] Systems Development Life Cycle (SDLC) has 5 stages such as planning, analysis, design, implementation, and maintenance (Rhodes, 2012) page 1.

In several studies above, no one has conducted an analysis related to audio recordings with different types of sound with different objects. So that this research is expected to be able to become a guide in the analysis of audio recordings, especially different audio recordings between objects.

Fig.1. SDLC stages

Source: The Systems Development Life Cycle (SDLC) as a Standard: Beyond the Documentation (2012).

• 1)    Planning or the planning stage aims to identify and prioritize the system being developed, and what it wants to achieve. Planning is also the initial stage of the process of developing a framework. Where aims to extract the stages in the framework and audio forensic investigation techniques and the targets to be achieved.

• 2)    The analysis is the research phase of an existing system to design a new system or update an existing system. At this stage, literature study activities are carried out to determine a case that can be handled by the system, as well as to identify the previous system for system development. The analysis process is carried out on the evidence found which will later be used in identifying the crimes that occurred and then submitted to support the trial process.

• 3)    The design or system design stage is the stage for determining the process stages or techniques for implementing a new system or a system developed from the previous system. The design process also requires an analysis of the function of each stage or the technique is built. Where this stage is the process of eliminating the same stages in the framework and the audio forensic investigation technique which is used as a reference for developing the framework.

• 4)    Implementation or the implementation stage is the stage for implementing a design that is built to be developed and conducting trials on the system. At this stage, the framework development process will be carried out based on the stages of the framework and previous audio forensic investigation techniques. The framework development process will be made in the form of a state chart diagram using the Microsoft Visio program. The form of the framework development will be made sequentially based on the initial stages and sub-stages from the beginning to the final stage to form a complete framework so that it can be used for audio forensic investigations.

• 5)    The maintenance stage is the process of maintaining the system during use to remain able to operate properly. In the process of developing a digital audio identification framework in this study using the Systems Development Life Cycle (SDLC) method, this method is used because at the time of framework development there will be several stages that will be added and eliminated or removed without maintaining the meaning or initial arrangement of the existing framework. This framework is expected to be able to meet the standards for forensic investigation and handling of audio evidence/sound recordings.

The Application of Digital Forensics identifies the human voice using SDLC.

Figure 2 explains that this research methodology was used based on a review of previous related studies. This research method aims to develop research that has existed before. In this research, can be used the application of Digital Forensics for Digital Audio identification using the Systems Development Life Cycle (SDLC) method. This research method includes 6 main stages, namely problem identification, literature study, development framework using SDLC, framework trial and framework feasibility test, and make conclusions with regard to the results of forensic audio framework development.

The explanations related to this research method are as follows:

• 1.    Problem Identification

• 2.    Literature Study

• 3.    Framework Development Using SDLC

That was the initial stage in research, this was done to obtain and found research topics that will be studied further to identify the problems needed for the application of digital forensics in identifying digital audio using the SDLC method.

Fig.2. Research Methodology