Valve has updated Steam Trading to include Captcha security in a bid to prevent unauthorised trades from malware infected systems.
Malware can cause computers to make Steam trades without users' awareness, which Valve hopes they can tackle with the new feature.
Captcha usually asks people to input a series of letters and numbers from an image in order to prove that someone is human. It seems Valve is using Google's reCaptcha system rather than its own, according to Steam Database.
Valve's John Cook admitted the update would cause "a bit of hassle" in an update on the Steam Community forums, but he believes it will be worthwhile.
"We know it's a bit of a hassle," he commented.
"And we don't like making trading harder for users, but we do expect it to significantly help customers who are tricked into downloading and running malware from losing their items."
There was a mixed response to the news, with some users asking for an option to turn off the feature. Cook said that some third-party trading services have been excluded from its Captcha feature so not all users will notice a difference.
Valve has now switched from their own captcha to the new version of Google's reCAPTCHA. The "No CAPTCHA reCAPTCHA ". pic.twitter.com/oMIIcIh7KC
— Steam Database (@SteamDB) January 10, 2015