Electronic Design

Flexible Display Modules Offer New OTP Options

We’ve embraced the efficacy and security of one time password (OTP) protection for years. Why? Because it works in helping thwart the massive and devastating fraud and theft of corporate and consumer information. Such unscrupulous actions have cost financial institutions and other organizations billions of dollars.

The marketplace is rife with stories of massive fraud and theft—including the 2005 phishing scam involving e-mail, fake web sites, the 2006 attack on Citibank, and of course the massive 2007 TJ Maxx case.

Whether it’s time-synchronized OTP, non-mathematical algorithm types, two-factor authentication, or single OTP-over-SMS or transaction authentication numbers (TANs), OTP technology has proven to be one of the most trusted extra layers of protection to help stem the tide of fraud and theft. The success of OTP, lead by companies such as RSA, VASCO, and Verisign, has given rise to a half-billion-dollar industry in protecting restricted resources.

But let’s get real. The clunky design and single-use inefficiency of most OTP fobs and tokens has been the bane of design engineers for years, who have little or no option for anything else. OTP technology should be embedded in something more utilitarian, efficient, and cost-effective. One solution is the use of flexible display modules that can be embedded in most display card (credit card) applications.

This shift in technology may well be the death knell of conventional security tokens. OTP tokens and fobs can be bulky and not easy to carry. Lose or break one and you’re saddled with monumental inconvenience—there goes your productivity when time-critical access to a virtual private network (VPN), corporate networks, or financial institution servers can’t be accessed.

Flexible display modules (embedded with OTP and other functionality) that can be laminated into convenient cards are now a reality. Employing a hot-lamination processes, these convenient cards are a suitable high-volume, cost-sensitive solution for mass consumer manufacturing and security use.

The technology is based on electrochromics—basically a color change in a material caused by the application of an electric field—which has been generating significant interest in academia and industry for its potential commercial applications. One current application is its use in automatically dimming rear view mirrors in automobiles. Traditional electrochromic materials rely on a “redox dye” that must serve as both the redox material and the color-changing agent, resulting in an unsatisfactory tradeoff between contrast, lifetime (number of cycles), and available color sets.

New chemistries have been used to create products that add further value by separating the function of the redox material from the dye. These systems are based on two electrochemical-chemical principles. First, a reversible oxidation-reduction (redox) material is used to create a pH gradient. Second, a pH-sensitive dye responds to the change in pH, resulting in the formation of a high-contrast, reflective image.

By separating the function of the redox material and the dye, these new inks provide a family of high-contrast materials that are inherently stable and versatile, and can also be processed. Further, by requiring only one redox couple for producing the pH change, this technology offers more color flexibility and longer life compared with systems that require a new redox couple for each color.

Offering the same quality assurance of contemporary credit cards (though with viewing angles more like paper and a viewability index closer to newsprint) and with a lifespan of three years or more, OTP cards vastly improve the convenience factor for end users. These OTP cards deliver higher contrast displays that are easier to read and less likely to be broken or misplaced. And they can be stored in a wallet or purse instead of being tethered to a keychain or briefcase or left loose.

There are several models available that offer low voltage and power requirements, high-contrast and sunlight-readable displays, shock and vibration resistance, name-brand embedded microcontrollers, a 10,000-cycle lifetime, and the aforementioned hot-lamination compatibility. The currently available six-digit, seven-segment numeric display modules are suitable for ISO-compliant card applications (from 25 microns to 450 microns, depending on device construct, and operating temperatures from -5°C to 50°C). This includes support for OTP technology with two-factor authentication security.

The cost savings are significant over the lifetime of ownership. Simple economics dictate that card issuance, even using snail mail, is more cost effective than fobs or tokens. And research has shown that 99 percent of the time users feel more secure knowing their OTP-enabled card is safely tucked away in a wallet or purse, and not flopping loose like a token.

Card marketing can include “loyalty” or branded cards. Most fobs and tokens, because of their awkward sizes and shapes, offer no meaningful printable space for a company to apply brands, logos, phone numbers, or other instructional or display information. OTP cards, like those issued by PayPal, offer printable space coupled with fraud-stopping OTP technology. They can also embed other technologies.

Flexible module technology can be employed in a broad range of end-user applications such as consumer electronics, sensors and diagnostics, and smart labels. It can also help combine other security functions with payment and physical access technology into a single card. Though security and ease of use put OTP cards in front of conventional OTP fobs, widespread consumer adoption may take time. Deployment in Europe and other regions is already widespread, where users are discovering its convenience, cost efficiency, and improved design.

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