PdfPKCS7 .verify（）在签名验证时返回false

Question

我一直在使用itextSharp-5.5.5（5.5.10 / 5.5.13）所有版本都有问题。

let duration = playerItem.duration //set duration of currently playing item
let interval = CMTimeMake(1, 1)
player?.addPeriodicTimeObserver(forInterval: interval, queue: DispatchQueue.main, using: { [weak self] time in
                let totalDurationSeconds = CMTimeGetSeconds((self?.duration)!)

                let durationSeconds = CMTimeGetSeconds(time)
                let currentProgress = Float(durationSeconds / totalDurationSeconds)
                self?.progressView.setProgress(currentProgress, animated: true)
            })

但是Adobe Acrobat Reader说：已签名并且所有签名均有效。

任何帮助，不胜感激。