The Battle Against Pornography Continues

Computerworld - Our security team's goal is to provide the company with freedom from fear. Management is afraid of pornography, afraid of the bandwidth and time wasted on it, and even more afraid of lawsuits from offended staff. I don't think the problem within our company is particularly bad, but because we take every issue seriously, we've spent some time addressing this.
I see four ways for pornography to get into or out of our building: on physical media, over Web connections, by way of e-mail attachments and over peer-to-peer file-sharing networks.
We do our best to ban peer-to-peer networks. But there's not a lot we can do about physical transport, considering the latest solid-state storage devices are the size of my thumb. But if anyone copies porn from such a device onto a PC, we'll find it eventually on the file shares or local drives.
We also do reporting on Web browsing activity. That has allowed us to track down the small number of people who view and download pornography over the Web.
That leaves e-mail as the last open door. We've added a few filters for particularly dreadful phrases to try to stop offensive spam, and our new antispam service should help filter out porn too. But there's always the risk that the e-mail service will be used to send and receive objectionable material, particularly in file attachments.
We'd like to find a way to block incoming e-mails that include pornographic image file attachments. We already use New York-based MessageLabs Inc.'s SkyScan antispam and antivirus services, and the managed service provider offers a service it claims can also protect us against pornographic pictures. But it has been difficult to arrange a test of that service.
Based on information on MessageLabs' Web site, it appears that the company uses First 4 Internet Ltd.'s Image Composition Analysis (ICA) software to perform this service. By chance, we were recently approached by a reseller of Banbury, England-based First 4's product.
I have a cynical view of the likely effectiveness of these tools. It's difficult enough for humans to decide about pornographic images, so it must be extremely hard for software to do it. This reseller, however, was willing to let us try ICA on our systems for 10 days.
It also offered us five CD-ROMs full of images to help us test the software. They contained images that included no porn, some porn, a whole lot of porn and total porn. One CD the reseller offered contained images graphic enough to frighten Larry Flynt.