人臉識別技術很厲害？用這一招即可騙過

人的臉型和指紋一樣具有明顯特征，所以越來越多的組織——從警察局到學校到沃爾瑪（Wal-Mart）——都在借助人臉識別軟件來甄別線上照片和真實場景中的人。

然而人臉識別技術也開始給個人隱私帶來很大的威脅，一些研究者開始探求反制措施，其中包括多倫多大學計算機工程系的學生喬伊·博斯。

博斯稱他開發了一種工具，可以在照片上傳到網絡前加入額外的元素，從而“打亂”人臉識別系統。用肉眼看，處理前后的照片沒有任何區別，但處理后的照片有隱藏了的特性，可以阻止檢測系統的運行。

博斯說：“這一工具可以給人臉圖像添加特殊制作的雜質，用于干擾人臉識別軟件，就像Instagram（圖片和視頻分享社交軟件——譯注）的過濾器。”

博斯告訴《財富》雜志，這個工具很快會以手機應用或者瀏覽器插件的形式出現，他也已經在GitHub（提供軟件源代碼托管服務網站——譯注）的個人主頁上分享了底層代碼。

在這個技術猖獗的時代，阻撓人臉識別系統運作的反制措施，或許會受到很多人的歡迎。

有些私企會動腦筋，比如抓住人們對校園槍擊案的焦慮，向校區推廣人臉檢測系統，盡管懷疑人士批駁這種系統反而造成了“安全威脅”，而且也不能阻止校園槍擊案的再次發生。而據《福布斯》（Forbes）上周的報道，亞馬遜網絡服務（ Amazon Web Services）正在向顧客售賣人臉識別技術，價格竟低至10美元。

這樣一來，博斯所開發的工具，通過減少人臉檢測軟件所需的有效人臉數量，就能減緩人臉識別技術的大范圍使用。

不過博斯的工具是預防性的，對于那些已經獲取真實人臉信息，或者使用探頭在真實世界監控人們的公司，這一工具就無能為力了。博斯認為，要預防此類的人臉識別，人們也可以使用一些技巧，比如帶特殊形狀的眼鏡以糊弄檢測系統，甚至在臉上貼點小標簽。

貓鼠游戲

目前博斯的工具只對某幾類的人臉識別軟件有效，說得具體點，就是它能破壞那些訓練模式（用于訓練軟件所設置的機器學習數據庫）可公開獲取的軟件。

有些安全軟件公司銷售的人臉檢測系統使用公開的數據庫，而有些則不是，最有名的是Facebook, 他們擁有自主產權的人臉檢測系統，博斯的工具對它就不能奏效。

博斯懷疑，Facebook可能是在綜合使用不同的人臉識別技術，以對付各種反制措施，比如他所開發的工具。但博斯認為他的人臉識別破壞軟件最終也能阻撓Facebook，從而開啟一場識別人臉技術的開發者和掩藏人臉技術的開發者之間的貓鼠游戲。

這也提出了一個問題，阻撓人臉識別的工具會不會被商業化。博斯說已有幾家風投找過他，但他決定暫不參與，今年秋季他會繼續他在麥吉爾大學的博士生研究項目。（財富中文網）

譯者：Hank?

The shape of your face is as distinct as your fingerprint. That’s why a growing number of organizations — from police forces to schools to Wal-Mart — are using facial recognition software to identify you in online photos and in real world locations.

But facial recognition technology is beginning to pose a major privacy threat, which has led researchers to explore ways to counteract it. One of them is Joey Bose, a computer engineering student at the University of Toronto.

Bose claims he has developed a tool to “break” facial recognition systems by adding extra elements to photos before they are uploaded to the Internet. The photos don’t look any different to the naked eye, but the hidden features thwart detection systems.

“It adds specially-crafted noise for the face images. It’s trained to attack facial recognition software,” he said. “Think of it as Instagram filter.”

Bose told Fortune the tool will soon be available as a phone app or plug-in for web browsers, and that he has shared the underlying code on his GitHub page.

This opportunity to thwart facial recognition will likely be welcome by many people at a time when the technology is becoming more pervasive.

Private companies, for instance, have seized on anxiety over school shootings to sell face-detection systems to school districts — even as skeptics pan this as “security theater” that’s unlikely to prevent more shootings. Meanwhile, Forbes last week reported that Amazon Web Services is selling facial recognition technology to all comers for as little as $10.

Bose’s could thus slow the spread of the technology by reducing the number of faces available to companies that make the detection software.

His tool, however, is only a pre-emptive measure and does not address situations where a company already has an image of someone’s face and uses a camera to detect them in the real world. In order to prevent this sort of recognition, Bose says, people can employ tactics like wearing glasses with special patterns that fool the detection mechanisms or even put small stickers on their face.

A Cat-and-Mouse Game

For now, Bose’s tool only works to thwart certain types of facial recognition software. Specifically, it can break the software if the training model — the machine learning data set used to train the software — is publicly available.

While a number of facial detection systems sold by security companies rely on these publicly available data sets, other companies, notably Facebook, have their own proprietary versions that Bose’s tool can’t defeat.

Bose suspects that Facebook uses an ensemble of different facial recognition techniques in order to overcome counter-measures, like the one he developed, to fool its software. But he predicts his facial recognition duping tool will eventually be able to thwart Facebook, and set off a cat-and-mouse game between developers seeking to detect faces and those seeking to disguise them.

This raises the question of whether companies will seek to commercialize tools that thwart facial recognition. Bose says he has already been approached by a number of venture capitalists, but that he’s decided to pass for now. Instead, he says he plans to continue his research in a PhD program at McGill University starting this fall.