In recent years, a new trend has come up, which is that of reading the digital Quran online. This text was revealed more than 1400 years ago in the Arabic language and has been protected from all possible ways of distortion until today. Unfortunately, driven by the desire to make profit or gain publicity, fraudsters have started modifying certain Quranic verses. These alterations are misleading many people who are thus deprived of the original and accurate message of the Holy Quran. This paper focuses on systematically analyzing and categorizing existing research related to preserving and verifying the content integrity of the Quran. This paper further assesses these existing studies in terms of their evaluation parameters and findings. We find that the existing studies can be classified according to their format and methods, i.e., the online formats in which the Quranic content is available, methods employed to protect the Quranic content from modification, and last methods of verification. This paper concludes with the issue of future challenges and their possible solutions.
