Some manufacturers deploy physical authentication tokens in the form of a flash drive. These are used to control access to a sensitive system by containing encryption keys or, more commonly, communicating with security software on the target machine. The system is designed so the target machine will not operate except when the flash drive device is plugged into it. Some of these "PC lock" devices also function as normal flash drives when plugged into other machines.

Flash drives may present a significant security challenge for some organizations. Their small size and ease of use allows unsupervised visitors or employees to store and smuggle out confidential data with little chance of detection. Both corporate and public computers are vulnerable to attackers connecting a flash drive to a free USB port and using malicious software such as keyboard loggers or packet sniffers.
“The solid state flash drive can theoretically achieve incredibly high transfer speeds, blurring the line between an external solid state drive and a flash drive,” our tester raved. He did note he was “unable to reach higher than half the listed read and write speeds.” However, he explained, “The Extreme Pro is still very fast compared to other USB 3.0 flash drives.” In the end, our tester recommended this flash drive “with the caveat that there's a good chance you won't see those 300+ MB/s transfer speeds.” He also added that for just a little more, you could invest in an external hard drive—if the ultra-compact form factor isn’t important in your buying decision.
“The Samsung BAR is incredibly small and easily portable, measuring just under 2-inches long,” our tester said. He added, “It's also extremely durable: waterproof, shockproof, as well as x-rays and magnets [proof].” The included key ring adds to its portability, according to our reviewer. On the flip side, he called the transfer speeds “decent but mostly unremarkable.” Our tester concluded, “Most of the BAR's problems are due to Samsung releasing a newer, cheaper model, the BAR Plus.”
With their paper-slim profiles, Ultrabooks and tablets are barely thick enough for a USB port. That's why some of the bulkier drives on this list are not ideal for those devices. Meanwhile, Samsung’s Fit drives are slim and compact, about the size of your thumb nail. This unobtrusive storage is constructed with a metal casing that is resistant to the elements and NAND flash technology. With USB 3.0 tech you can expect fast read speeds, while the price is easy to stomach. Just make sure to attach it to a lanyard, so you don't lose it.
^{“The Samsung BAR is incredibly small and easily portable, measuring just under 2-inches long,” our tester said. He added, “It's also extremely durable: waterproof, shockproof, as well as x-rays and magnets [proof].” The included key ring adds to its portability, according to our reviewer. On the flip side, he called the transfer speeds “decent but mostly unremarkable.” Our tester concluded, “Most of the BAR's problems are due to Samsung releasing a newer, cheaper model, the BAR Plus.”}
Flash drives are often measured by the rate at which they transfer data. Transfer rates may be given in megabytes per second (MB/s), megabits per second (Mbit/s), or in optical drive multipliers such as "180X" (180 times 150 KiB/s).[19] File transfer rates vary considerably among devices. Second generation flash drives have claimed to read at up to 30 MB/s and write at about half that rate, which was about 20 times faster than the theoretical transfer rate achievable by the previous model, USB 1.1, which is limited to 12 Mbit/s (1.5 MB/s) with accounted overhead.[20] The effective transfer rate of a device is significantly affected by the data access pattern.[21]
_{Specially manufactured flash drives are available that have a tough rubber or metal casing designed to be waterproof and virtually "unbreakable". These flash drives retain their memory after being submerged in water, and even through a machine wash. Leaving such a flash drive out to dry completely before allowing current to run through it has been known to result in a working drive with no future problems. Channel Five's Gadget Show cooked one of these flash drives with propane, froze it with dry ice, submerged it in various acidic liquids, ran over it with a jeep and fired it against a wall with a mortar. A company specializing in recovering lost data from computer drives managed to recover all the data on the drive.[64] All data on the other removable storage devices tested, using optical or magnetic technologies, were destroyed.}
Usually, such drives will be custom-stamped with a company's logo, as a form of advertising. The drive may be blank, or preloaded with graphics, documentation, web links, Flash animation or other multimedia, and free or demonstration software. Some preloaded drives are read-only, while others are configured with both read-only and user-writable segments. Such dual-partition drives are more expensive.[61]
Capacity - More so than any other feature, capacity will drive the price of a flash drive up the most. So before you make a purchase, consider how much you’re willing to spend on a flash drive and weigh that against how much capacity you’ll likely need. A flash drive with 16GB can cost you as little as $10, while a 128GB one will run up to $60 or more.
Counterfeit USB flash drives are sometimes sold with claims of having higher capacities than they actually have. These are typically low capacity USB drives which are modified so that they emulate larger capacity drives (for example, a 2 GB drive being marketed as a 64 GB drive). When plugged into a computer, they report themselves as being the larger capacity they were sold as, but when data is written to them, either the write fails, the drive freezes up, or it overwrites existing data. Software tools exist to check and detect fake USB drives,[43][44] and in some cases it is possible to repair these devices to remove the false capacity information and use its real storage limit.[45]
Floppy disk hardware emulators exist which effectively utilize the internal connections and physical attributes of a floppy disk drive to utilize a device where a USB flash drive emulates the storage space of a floppy disk in a solid state form, and can be divided into a number of individual virtual floppy disk images using individual data channels.

You can get USB 3.0 speed in a compact and durable metal USB drive from Kingston for under $10. It sports a capless design with a sturdy keyring, perfect for travel or as a part of your everyday carry. The design can even be customized to add your logo or company name. Read speeds top 100 Mb/s, while write speeds are on the slow end. With a five-year warranty, a great design, and a value price, this small drive makes a perfect addition to your keyring. 

The New York-based Human Rights Foundation collaborated with Forum 280 and USB Memory Direct to launch the "Flash Drives for Freedom" program.[80][81] The program was created in 2016 to smuggle flash drives with American and South Korean movies and television shows, as well as a copy of the Korean Wikipedia, into North Korea to spread pro-Western sentiment.[82][83]
^{With wide deployment(s) of flash drives being used in various environments (secured or otherwise), the issue of data and information security remains important. The use of biometrics and encryption is becoming the norm with the need for increased security for data; on-the-fly encryption systems are particularly useful in this regard, as they can transparently encrypt large amounts of data. In some cases a secure USB drive may use a hardware-based encryption mechanism that uses a hardware module instead of software for strongly encrypting data. IEEE 1667 is an attempt to create a generic authentication platform for USB drives. It is supported in Windows 7 and Windows Vista (Service Pack 2 with a hotfix).[47]}

USB flash drives are often used for storage, data back-up and transfer of computer files. Compared with floppy disks or CDs, they are smaller, faster, have significantly more capacity, and are more durable due to a lack of moving parts. Additionally, they are immune to electromagnetic interference (unlike floppy disks), and are unharmed by surface scratches (unlike CDs). Until about 2005, most desktop and laptop computers were supplied with floppy disk drives in addition to USB ports, but floppy disk drives became obsolete after widespread adoption of USB ports and the larger USB drive capacity compared to the 1.44 MB 3.5-inch floppy disk.

On the more practical side our flash drives, also called thumbdrives or memory sticks are available in memory capacities from 64MB to 256GB. With memory capacities like that, we certainly have the options to cover whatever your data storage requirements may be. For more information on data storage capacities, check out our USB Flash Drive Capacity Guide.
“The transfer speeds are satisfyingly fast for reading and writing all kinds of files, whether large HD videos or unsorted media folders,” our tester reported of this flash drive. He also liked the inclusion of the SecureAccess file encryption, although advanced features are an additional purchase. In terms of negatives, our reviewer called the plastic shell casing “flimsy and fragile” and observed that the transfer speeds are capped when the flash drive is plugged into a USB hub. Overall? Our tester was “more than satisfied with the transfer speeds, but would have appreciated a better, sturdier physical design.”
_{Some manufacturers deploy physical authentication tokens in the form of a flash drive. These are used to control access to a sensitive system by containing encryption keys or, more commonly, communicating with security software on the target machine. The system is designed so the target machine will not operate except when the flash drive device is plugged into it. Some of these "PC lock" devices also function as normal flash drives when plugged into other machines.}

Flash memory combines a number of older technologies, with lower cost, lower power consumption and small size made possible by advances in microprocessor technology. The memory storage was based on earlier EPROM and EEPROM technologies. These had limited capacity, were slow for both reading and writing, required complex high-voltage drive circuitry, and could be re-written only after erasing the entire contents of the chip.

Not everyone wants every file they've ever created available in the cloud. It can put data at risk - not just from hackers or spammers or nosey bosses, but with some providers offering shady terms, you could lose the intellectual rights to anything uploaded. Having a portable memory drive means you don't have to sacrifice mobility for security, though, making flash drives an ideal solution for business people on the go.