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What is cryptography?

At a glance

  • Cryptography is the use of mathematical techniques to secure data from unauthorized third parties.
  • Cryptography can include secret keys, public keys and hash functions.
  • If you’re interested in a career involving cryptography, a bachelor’s degree in computer science, information technology or a related field may be required.
  • If information technology or cybersecurity interests you, learn about online technology degree programs at University of Phoenix.

At its core, cryptography is the practice of encoding and decoding messages to prevent unauthorized access. This concept has existed for thousands of years, and its evolution has been shaped by human ingenuity and the changing landscape of technology.

In ancient times, cryptography was used as a means of communication between military commanders during times of war. One of the earliest examples of encryption was the Caesar Cipher, invented by Julius Caesar more than 2,000 years ago. This simple encryption technique involved shifting each letter in a message by a fixed number of positions down the alphabet. The key, or the number of positions shifted, was known only to the sender and the recipient.

Fast-forward to the modern era and cryptography has become an integral part of our daily lives. Cryptography is the use of mathematical techniques to shape data and prevent it from being seen, used or changed by unauthorized parties. We use it to protect our online transactions, secure our communications and guard our personal information. 

Cryptography can be broadly divided into two categories: symmetric-key cryptography and public-key cryptography. In symmetric-key cryptography, the same secret key is used for both encryption and decryption. The sender and the receiver must share the same key, which can be challenging in situations where the parties have never met.

On the other hand, public-key cryptography, also known as asymmetric key cryptography, involves the use of two keys — a public key and a private key. The public key used to encrypt messages is freely available. The private key, which is kept secret, is used to decrypt the messages. Asymmetric-key cryptography has revolutionized the industry by making it possible for secure communication to take place over insecure networks.

Where is cryptography is used

Cryptography has been leveraged across a wide variety of industries. Consider the following:


Cryptography has numerous applications in the modern world, most notably in online security. With the rise of e-commerce and online banking, there is a greater need for secure transactions over the internet. Cryptography is used to protect the transmission of sensitive data such as credit card numbers, passwords and other personal information.


Cryptography is still used in military and intelligence operations. During times of war, cryptography can make the difference between victory and defeat. Governments and militaries use sophisticated encryption techniques to protect their communication and keep their strategies secret.

Intellectual property

In the field of digital rights management, cryptography is used to protect digital content such as music, movies and books from unauthorized access and distribution.


Cryptography is the practice of securing communication in the presence of outside third parties. It protects sensitive information from being accessed by unauthorized parties, such as hackers or other malicious actors. It transforms data into an unreadable form without an encryption key. Cryptography also provides authentication, allowing two parties to communicate securely with each other and verify identities.

How is cryptography used in cybersecurity?

Cryptography is a technique that is often used in cybersecurity to protect information. It relies on algorithms to encode data so that only someone with the correct key can decode it. This key could be a password, a physical key or another type of secret code.

The purpose of cryptography is to make it difficult for unauthorized individuals to access data, even if they intercept it. Securing this data is an essential part of cybersecurity, and cryptography is one of the main techniques to protect data from unauthorized access.

Organizations that handle sensitive information, such as financial institutions or government agencies, often use cryptography.

Types of cryptography

Cryptography encompasses a variety of techniques and algorithms. The most common techniques include a secret key, a public key and hash functions.

Secret key

In cryptography, a secret key is a piece of information or framework used to encrypt and decrypt messages. Each participant in a private communication has access to a shared secret key. The system’s level of security depends on both the strength of the encryption algorithm and the secrecy of the key. The key must be known only to the sender and receiver of the message. If the key is compromised, the security of the system is compromised.

Public key

A public key is a large numerical cryptographic key used to scramble data. Unlike a secret key, which is kept private, the public key is shared with everyone in the network. The only way to decrypt a message using one key is to use the second key. This cryptography is often used in online banking, email and file-sharing applications.

Hash functions

Hash functions are algorithms that accept inputs of any size and generate what is known as a hash, or a fixed-length output. Cryptographic hash functions are intended to be one-way functions, meaning it is difficult or impossible to reverse the process and use the hash to determine the original input. This makes them helpful in verifying a data set has not been tampered with or corrupted. They are also used in digital signatures and to protect passwords. Careers in cryptography

A career in cryptography can involve various tasks, such as designing and implementing encryption algorithms and protocols, developing software that uses cryptographic techniques, auditing systems for security vulnerabilities or researching new cryptographic algorithms.

As technology becomes more sophisticated, the need for cryptography professionals will only continue to grow, which means jobs in cryptography may become increasingly available. For example, demand for information security analysts is projected to grow by 32% from 2022 to 2032, according to the U.S. Bureau of Labor Statistics.

How to learn cryptography

To pursue a career in cryptography, individuals should be comfortable with math and computer programming. For example, to become an information security analyst, a bachelor’s degree in computer science, information technology or a related field is often recommended. Professional certification may also be required.

IT graduate-level programs often teach encryption and cryptography methods. Graduate-level programs can offer advanced courses on cryptography and encryption. They can also give students research opportunities to learn more about specific topics to better prepare for a professional setting.

Many more options are available, such as online courses, boot camps and self-study materials.

Cryptography has become an essential tool for securing digital communication, protecting personal information and ensuring the integrity of online transactions. As we look to the future, the field of cryptography will likely continue to evolve and shape the way we interact with technology.

Information technology programs at University of Phoenix

Whether you’re seeking to gain a basic understanding of information technology or cybersecurity, or you’re a working professional looking to expand your skill set, University of Phoenix (UOPX) offers online course collections and bachelor’s and master’s degrees to help you meet your goals. Learn more about undergraduate and graduate online technology degrees from UOPX and start your IT journey today!

  • Associate of Arts in Information Technology — This IT program introduces you to information technology concepts and principles in programming, data analytics, cybersecurity and networking. Learn the essential foundation of technical skills necessary for additional skill building as you enter the IT field.
  • Bachelor of Science in Information Technology — In this program, you’ll learn skills like business process, cybersecurity, information systems, operations and systems analysis.
  • Bachelor of Science in Computer Science — This program equips you with the knowledge to apply information technology theory and principles to address real-world business challenges with advanced concepts in math, programming and computer architecture. You can also use elective courses to earn a certificate in cybersecurity, networking, cloud computing and much more.
  • Bachelor of Science in Cybersecurity — This online program teaches skills such as security policies, network security, cybersecurity and more.
  • Certified Ethical Hacker Course Collection — This course collection can help you prepare for the EC-Council Certified Ethical Hacker (CEH) certification exam. Topics include the phases of ethical hacking, recognizing weaknesses and vulnerabilities of a system, social engineering, IoT threats, risk mitigation and more.
  • Certified Incident Handler Course Collection — This course collection can help you prepare for the EC-Council Certified Incident Handler (ECIH) certification exam. This specialist certification focuses on how to effectively handle security breaches. 
  • Certified Network Defender Course Collection — This course collection can help you prepare for the entry-level EC-Council Certified Network Defender (CND) certification exam. Courses focus on protecting a network from security breaches before they happen.
  • Computer Hacking Forensics Investigator Course Collection — This course collection can help you prepare for the EC-Council Computer Hacking Forensics Investigator (CHFI) certification exam. You’ll learn about the latest technologies, tools and methodologies in digital forensics, including the dark web, IoT, malware, the cloud and data forensics.
Headshot of Michael Feder


A graduate of Johns Hopkins University and its Writing Seminars program and winner of the Stephen A. Dixon Literary Prize, Michael Feder brings an eye for detail and a passion for research to every article he writes. His academic and professional background includes experience in marketing, content development, script writing and SEO. Today, he works as a multimedia specialist at University of Phoenix where he covers a variety of topics ranging from healthcare to IT.

Headshot of Kathryn Uhles


Currently Dean of the College of Business and Information Technology, Kathryn Uhles has served University of Phoenix in a variety of roles since 2006. Prior to joining University of Phoenix, Kathryn taught fifth grade to underprivileged youth in Phoenix.


This article has been vetted by University of Phoenix's editorial advisory committee. 
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