【综合】数字签名Crash修复

PDF Office/PDF Master/Class/DigtalSignature/ViewControllers/CDSignatureCertificateStateViewController.swift

@@ -45,7 +45,7 @@ class CDSignatureCertificateStateViewController: NSViewController {
             self.imageView.image = NSImage(named: "ImageNameSigntureLargeVerifySuccess")
             
             let cer = signer?.certificates.first
-            let CNStr = cer?.subjectDict["CN"] as! String
+            let CNStr = cer?.subjectDict["CN"] as? String ?? ""
             self.subTitleLabel.stringValue = String(format: NSLocalizedString("Signature is VALID, signed by %@.", comment: ""), CNStr)
             self.subDes1Label.stringValue = String(format: "- %@",NSLocalizedString("The document has not been modified since this signature was applied.", comment: ""))
             self.subDes2Label.stringValue = String(format: "- %@",NSLocalizedString("The signer's identity is valid.", comment: ""))