Silence and law, although seemingly opposing concepts, are in fact deeply connected. Law is expressed in words, while silence is often perceived as an absence of will. Yet the two notions are intimately intertwined. This analysis of the relationship between silence and criminal law shows that silence is both subject and object. On the one hand, it exposes gaps in the law, creating grey areas and legal uncertainty. On the other hand, the law attempts to control this silence, attributing legal value to it, whether as tacit consent or as a punishable offence. This duality raises crucial questions about the predictability and clarity of criminal law, revealing the dilemmas faced by litigants. Through in-depth analysis, this work sheds light on the mysteries of silence in criminal law, a silence that is imposed or proscribed, equivocal and rich in meaning. The legal uncertainty arising from this ambivalence highlights the urgent need to clarify the role of silence in criminal law.