What is Cryptography? | University of Delaware Online

What Is Cryptography?

The cybersecurity field is enjoying robust growth with an 18 percent increase in jobs projected by 2024.1 One of the hottest subspecialties in cybersecurity is cryptography, the practice of securing computer data transmission and authentication through sophisticated scrambling and unscrambling algorithms.2

A Brief History

Cryptography dates back thousands of years. The term derives from the Greek word kryptos or "hidden." One of its earliest forms was ancient Greek hieroglyphics, coded messages created through a combination of letters and drawings.3 Thomas Jefferson devised intricate forms of cryptography for early U.S. government correspondence concerning sensitive matters, including the Louisiana Purchase.4

Today, cryptography refers primarily to data encryption — converting plaintext or "normal" computer language into coded ciphertext that can be transmitted from one authorized user to another without being intercepted or "hacked." Once the data transmission is complete, the process is reversed or decrypted. The recipient accesses the data as the original, unaltered plaintext.3

Many of these encrypted transmissions, such as online credit card transactions, happen without the user giving them much thought. That changes after a major breach like when discount retailer Target had 40 million customer accounts hacked in 2013.5

The Front Lines of Cybersecurity

These occasional massive breaches are a reminder that cryptography is not a static field. In the ongoing battle between hackers and cybersecurity professionals, cryptographers are on the front lines. Hackers continue to design new forms of malware — short for "malicious software" — designed to infect an unsuspecting user’s computer through a virus.6 One of the most virulent forms is "ransomware." As the name suggests, ransomware seizes control of the user’s computer and holds it "hostage," demanding payment in exchange for returning control to the user or to prevent the hacker from releasing sensitive documents. Ransomware attacks increased 6,000 percent in 2016.7

Combatting cyberattacks requires vigilance. In 2016, the FBI asked Apple to devise a way to circumvent the encryption on the iPhone of a suspect in a California terrorist shooting. Apple refused on the grounds that the work-around would eventually fall into the hands of hackers, thus compromising the encryption on all iPhones.8

The Coming Cybersecurity Challenge

The next wave of development in cyberspace, quantum computers, will bring with it a new cybersecurity challenge. Unlike today’s computers, quantum computers won’t be restricted to using ones and zeroes. The ability to run vastly greater combinations of variables far more quickly will give quantum computers much greater capability. While this will be a tremendous boon to internet development, it will also bring a new threat: Quantum computers will be much better equipped to defeat existing encryption.

Already, Google has begun testing a prototype of a quantum-resistant algorithm dubbed New Hope, and in 2016, representatives of several major IT firms gathered in Toronto for an international workshop devoted to "quantum-safe cryptography."9

In cybersecurity, the frontier is always moving.

Learn More

If you’re intrigued by this fascinating career, consider enrolling in the Applied Cryptography course at the University of Delaware. This course, part of the university’s online Master of Science in Cybersecurity program, explores modern cryptography, including algorithms and cryptosystems, cryptanalysis and best practices for application and implementation of crypto in software systems. To learn more, visit the website or schedule a phone appointment with Admissions.


1 "Occupational outlook handbook." U.S. Bureau of Labor Statistics. https://www.bls.gov/ooh/computer-and-information-technology/information-security-analysts.htm (accessed April 6, 2017).

2 "The basic elements of a cryptographic system." IBM Knowledge Center. https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.2.0/com.ibm.zos.v2r2.csfb500/csfb500_The_basic_elements_of_a_cryptographic_system.htm.

3 Rouse, M. "Cryptography." TechTarget. http://searchsoftwarequality.techtarget.com/definition/cryptography.

4 Doyle, R. "The founding fathers encrypted secret messages, too." The Atlantic. https://www.theatlantic.com/science/archive/2017/03/h3ll0-mr-pr3s1d3nt/521193/.

5 Wallace, G. “Target credit card hack: What you need to know.” CNN/Money. http://money.cnn.com/2013/12/22/news/companies/target-credit-card-hack/ (accessed April 6, 2017).

6 "What is malware and how can we prevent it?" PC tools. http://www.pctools.com/security-news/what-is-malware/.

7 Taylor, H. "Ransomware spiked by 6,000% in 2016 and most victims paid the hackers, IBM finds." CNBC. http://www.cnbc.com/2016/12/13/ransomware-spiked-6000-in-2016-and-most-victims-paid-the-hackers-ibm-finds.html (accessed April 6, 2017).

8 Rubenking, N. "The Best Encryption software of 2017." PC. http://uk.pcmag.com/encryption-products/83976/guide/the-best-encryption-software-of-2017.

9 Hutchinson, A. "Hacking, cryptography and the countdown to quantum computing." The New Yorker. http://www.newyorker.com/tech/elements/hacking-cryptography-and-the-countdown-to-quantum-computing.

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