CloudTrail log file validation creates a digitally signed digest file containing a hash of each log that CloudTrail writes to S3. These digest files can be used to determine whether a log file was changed, deleted, or unchanged after CloudTrail delivered the log. It is recommended that file validation be enabled on all CloudTrails.
Enabling log file validation will provide additional integrity checking of CloudTrail logs.
Perform the following to enable log file validation on a given trail:
From Command Line:
aws cloudtrail update-trail --name --enable-log-file-validation
Note that periodic validation of logs using these digests can be performed by running the following command:
aws cloudtrail validate-logs --trail-arn --start-time --end-time