Lunar crescent is an astronomical phenomenon which occurred due to the imposition of earth shadow from solar ray to the moon surface. Numbers of civilisations apply this phenomenon particularly the lunar crescent first visibility to determine the dates of religious significance.Since the lunar crescent visibility is dependent on the observer, its visibility is subjective to the physiology of the observer, weather condition, the brightness of the sky and the lunar crescent and the instrument used during the observation. As the variables that can affect the visibility of the lunar crescent are large, there are numbers of lunar crescent visibility reports that seem to be in contradiction to each other. An algorithm is designed to act as an authentication tool for the lunar crescent visibility report. The algorithms must wholly consider all the astrophysical factor of lunar crescent visibility, which are atmospheric extinction, observer physiology, sky and lunar brightness, contrast threshold and type of observation, naked eye, or optically aided observation. In the test, it is found that the designed algorithm has the success rate of 78% per cent in predicting the visibility of lunar crescent from the report of lunar crescent visibility in 2014 until 2021. This indicates the algorithm reliability in authenticating the report of contestable lunar crescent visibility sighting. However, an exhausting examination is required to exercise the algorithm reliability in prediction lunar crescent visibility in real condition. A discussion pertains around the factor of lunar crescent report contradiction is presented in this paper.