[KBA-78942] Digital signatures cannot be verified for exported video files that were recorded in Security Center 5.2 or 5.3

This article explains why the digital signature validation fails after exporting video files that were recorded in Security Center 5.2 or 5.3.

Symptoms

After upgrading to Security Center 5.4 or later, if you export a video file that was recorded on a Security Center 5.2 or 5.3 system, the digital signature cannot be verified. In the Security Desk Vault, the Digital signature status is File tampered.

IMPORTANT: In Security Center versions earlier than 5.9.0.0, digital signatures were called video watermarks. Starting in Security Center 5.9.0.0, a video watermark refers to an optional text overlay that can be permanently added to exported video files. It is a deterrent to prevent users from leaking video recordings.

Cause

Starting in SQL Server 2008, Microsoft changed the Transact-SQL datetime data type. The timestamp Accuracy is now rounded to increments of .000, .003, or .007 seconds. As a result, when you export a video file with a timestamp that differs from the latest datetime format in SQL, the first frame is excluded from the video sequence which affects the digital signature.

Workaround

Use the Archive storage details task to export the G64 files one at a time. If the exported file is still missing the first frame, you can find the original G64 file on your storage disk.

Status

Security Center systems 5.4 and later use the updated Transact-SQL datetime data type.