The reason why the file selection dialog box pops up is because the original signature file and the signature file are not in the same directory, or they are in the same directory but the original file name has changed. For example, if you sign. TXT to generate a TXT.SIG signature file, if you delete it or change the file name of. TXT to A 1. TXT At this point, a dialog box will appear when verifying the signed file, allowing you to select the original file.

The signature is not good, and the hint is clear. Signature verification failed, indicating that the original has been changed after signing.

Maybe the file you selected is not the original file at all, but a random file.