Perjury is the act of deliberately providing false information while under oath, typically during legal proceedings. This can occur in courtrooms, during depositions, or in sworn affidavits. The legal system relies on truthful testimony to ensure justice, and perjury undermines this process, potentially leading to wrongful convictions or the dismissal of valid claims. In many jurisdictions, perjury is considered a serious crime, often resulting in penalties such as fines or imprisonment. To prove perjury, it must be shown that the individual knowingly lied about a material fact, meaning the false statement could influence the outcome of the case.