Could a Doodle （涂鸦）Replace Your Password？ Nearly 80 percent of Americans own a smartphone，and a growing proportion of them use smartphones to surf the Internet，not just when they're on the go．This leads to people storing considerable amounts of personal and private data on their mobile devices．
    Often，there is just one layer of security protecting all that data--emails and text messages，social media profiles，bank accounts and credit cards，even other passwords to online services．It's the password that unlocks the smartphone's screen．Usually this involves entering a number，or just laying a fingertip on a sensor．
    Over the past couple of years，my research group，my colleagues and I have designed，created and tested a better way．We call it "user-generated free-form gestures，" which means smartphone owners can draw their own security pattern on the screen．It's a very simple idea that is surprisingly secure．
    1．IMPROVING TODAY'S WEAK SECURITY
    It might seem that biometric （生物识别的） authentication （认证），like a fingerprint，could be stronger．But it's not，because most systems that let a user allow fingerprint access also require a PIN （Personal Identification Number） or a password as a backup method．A user ─ or thief ─ could skip the biometric method and instead just enter （or guess） a PIN or a password．
    Compared to other methods，our approach dramatically increases the potential length and complexity of a password．Users simply draw a pattern across an entire touchscreen，using any number of locations on the screen．
    2．MEASURING DRAWINGS
    As users draw a shape or pattern on the screen，we track their fingers，recording the directions and speed．We compare that track to one recorded when they set up the gesture-based login．This protection can be added just by software changes；it needs no specific hardware or other modifications to existing touchscreen devices．As touchscreens become more common on laptop computers，this method could be used to protect them too．
    Our system also allows people to use more than one finger - though some participants wrongly assumed that making simple gestures with multiple fingers would be more secure than the same gesture with just one finger．The key to improving security using one or more fingers is to make a design that is not easy to guess．
    3．EASY TO DO AND REMEMBER，HARD TO BREAK
    Some people who participated in our studies created gestures that could be articulated as symbols，such as digits，geometric shapes （like a cylinder） and musical notations which are easy for them to remember．Even a relatively simple symbol，like an eighth note，can be drawn in so many different ways that calculating the possible variations is computationally intensive and consumes plenty of time．This is unlike text passwords，for which variations are simple to try out．
    4．REPLACING MORE THAN ONE PASSWORD
    Our research has extended beyond just using a gesture to unlock a smartphone．We have explored the potential for people to use doodles instead of passwords on several websites．It appeared to be easier to remember multiple gestures than it is to recall different passwords for each site．
    In fact，it was faster．Logging in with a gesture took two to six seconds less time than doing so with a text password．It's faster to generate a gesture than a password，too．People spent 42 percent less time generating gesture credentials than people we studied who had to make up new passwords．We also found that people could successfully enter gestures without spending as much attention on them as they had to with text passwords．
    Gesture-based interactions are popular and prevalent on mobile platforms，and are increasingly making their way to touchscreen-equipped laptops and desktops．The owners of those types of devices could benefit from a quick，easy and more secure authentication method like ours．

Could a Doodle Replace Your Password？
Passage outline	Detailed information
Introduction	An increasing number of people use smartphones for Internet （1） access/surfing access/surfing The free-form gesture drawn with a doodle is a very simple but surprisingly secure idea．
Characteristics	Improving today's weak security．	●A user or thief could skip fingerprint authentication by employing an（2） alternative alternative like just guessing a PIN or a password． ●In （3） comparison/contrast comparison/contrast to other methods，the password of our approach is dramatically longer and complex than that of other methods．
	Measuring drawings	●A shape or pattern drawn on the screen，we track where the user's fingers go and （4） how how quickly they move． ●To make a design with one or more fingers that is difficult to guess is of great（5） importance/significance importance/significance to the improvement of security．
	Easy to do and remember，hard to break	●Even a relatively simple symbol can be drawn in diverse ways so that the（6） calculation calculation of the possible variations is intensive and time-consuming．
	（7） Taking Taking the place of more than one password	●It is more（8） difficult difficult to recall different password for each site than to remember multiple gestures． ●Having new passwords（9） created/invented/generated/produed created/invented/generated/produed takes 42 percent more time than generating gesture credentials with a doodle．
Conclusion	Gesture-based interactions are gaining （10） currency/popularity currency/popularity and are widely applied to touchscreen-equipped laptops and desktops．