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What is Cryptography? Skip to main content Complete protection for your smartphone, payments, and personal data with Kaspersky Try it for free What is Cryptography? As the world becomes increasingly digital, the need for security has become ever more imperative. That’s where cryptography and its applications to cybersecurity come in. Essentially, the word refers to the study of secure communications techniques, but cryptography is closely associated with encryption, or the act of scrambling ordinary text into what’s known as ciphertext—and then back again into ordinary text (called plaintext) when it arrives at its destination. Several historical figures have been credited with creating and using cryptography through the centuries, from Greek historian Polybios and French diplomat Blaise de Vigenère to Roman Emperor Julius Caesar—who is credited with using one of the first modern ciphers—and Arthur Scherbius, who created the Enigma code-breaking machine during World War Two. Likely, none of them would recognize the ciphers of the 21 st century. But exactly what is cryptography? And, how does it work? Cryptography Definition Cryptography is the technique of obfuscating or coding data, ensuring that only the person who is meant to see the information–and has the key to break the code–can read it. The word is a hybrid of two Greek words: “kryptós”, which means hidden, and “graphein”, which means to write. Literally, the word cryptography translates to hidden writing, but in reality, the practice involves the secure transmission of information. The use of cryptography can be traced to the ancient Egyptians and their creative use of hieroglyphics. But, the art of coding has seen great strides over the millennia, and modern cryptography combines advanced computer technology, engineering, and maths—among other disciplines—to create highly sophisticated and secure algorithms and ciphers to protect sensitive data in the digital era. For example, cryptography is used to create various types of encryption protocols that are regularly used to protect data. These include 128-bit or 256-bit encryption, Secure Sockets Layer (SSL), and Transport Layer Security (TLS). These encryption protocols protect all manner of digital information and data, from passwords and emails to ecommerce and banking transactions. There are different cryptographic types, which are useful for different purposes. For example, the simplest is symmetric key cryptography. Here, data is encrypted using a secret key, and then both the encoded message and the secret key are sent to the recipient for decryption. Of course, the problem here is that if the message is intercepted, the third party can easily decode the message and steal the information. To create a more secure system of encoding, cryptologists devised asymmetric cryptography, which is sometimes known as the “public key” system. In this instance, all users have two keys: one public and one private. When creating a coded message, the sender will request the recipient’s public key to encode the message. This way, only the intended recipient’s private key will decode it. This way, even if the message is intercepted, a third party cannot decode it. Why is cryptography important? Cryptography is an essential cybersecurity tool. Its use means that data and users have an additional layer of security that ensures privacy and confidentiality and helps keep data from being stolen by cybercriminals. In practice, cryptography has many applications: Confidentiality: Only the intended recipient can access and read the information, so conversations and data remain private. Integrity of data: Cryptography ensures that the encoded data cannot be modified or tampered with enroute from the sender to the receiver without leaving traceable marks— an example of this is digital signatures. Authentication: Identities and destinations (or origins) are verified. Non-repudiation: Senders become accountable for their messages since they cannot later deny that the message was transmitted—digital signatures and email tracking are examples of this. What is cryptography in cybersecurity? Interest in the use of cryptography grew with the development of computers and their connections over an open network. Over time, it became obvious that there was a need to protect information from being intercepted or manipulated while being transmitted over this network. IBM was an early pioneer in this field, releasing its “Lucifer” encryption in the 1960s—this eventually became the first Data Encryption Standard (DES). As our lives become increasingly digital, the need for cryptography to secure massive amounts of sensitive information has become even more imperative. Now, there are many ways in which cryptography is crucial in the online space. Encryption is an essential part of being online, since so much sensitive data is transmitted everyday. Here are a few real-life applications: Using virtual private networks (VPNs) or protocols such as SSL to browse the internet safely and securely. Creating limited access controls so that only individuals with the correct permissions can carry out certain actions or functions, or access particular things. Securing different types of online communication, including emails, login credentials, and even text messages—such as with WhatsApp or Signal—through end-to-end encryption. Protecting users from various types of cyberattacks, such as man-in-the-middle attacks . Allowing companies to meet legal requirements, such as the data protections set out in the General Data Protection Regulation (GDPR). Creating and verifying login credentials, especially passwords . Allowing the secure management and transaction of cryptocurrencies. Enabling digital signatures to securely sign online documents and contracts. Verifying identities when logging into online accounts. What are the types of cryptography? Cryptography definitions are, understandably, quite broad. This is because the term covers a wide range of different processes. As such, there are many different types of cryptographic algorithms, each one offering varying levels of security, depending on the type of information being transmitted. Below are the three main cryptographic types: Symmetric Key Cryptography: This simpler form of cryptography takes its name from the fact that both the sender and receiver share one key to encrypt and decrypt information. Some examples of this are the Data Encryption Standard (DES) and Advanced Encryption Standard (AES). The main difficulty here is finding a way to securely share the key between the sender and receiver. Asymmetric Key Cryptography: A more secure type of cryptography, this involves both the sender and receiver having two keys: one public and one private. During the process, the sender will use the receiver’s public key to encrypt the message, while the receiver will use their private key to decrypt it. The two keys are different, and since only the receiver will have the private key, they will be the only ones able to read the information. The RSA algorithm is the most popular form of asymmetric cryptography. Hash Functions: These are types of cryptographic algorithms that do not involve the use of keys. Instead, a hash value—a number of fixed lengths that acts as a unique data identifier—is created based on the length of the plain text information and used to encrypt the data. This is commonly used by various operating systems to protect passwords , for example. From the above, it is clear that the main difference in symmetric and asymmetric encryption in cryptography is that the first only involves one key while the second requires two. Types of symmetric cryptography Symmetric encryption is sometimes called secret key cryptography because one single—purportedly—secret key is used to encrypt and decrypt information. There are several forms of this type of cryptography, including: Stream ciphers: These work on a single byte of data at a time and regularly change the encryption key. In this process, the keystream can be in tandem with—or independent of the message stream. This is called self-synchronizing or synchronous, respectively. Block ciphers: This type of cryptography—which includes the Feistel cipher—codes and decodes one block of data at a time. Forms of asymmetric key cryptography Asymmetric cryptography—sometimes referred to as public-key encryption—hinges on the fact that the receiver has two keys in play: a public one and a private one. The first is used by the sender to encode the information, while the receiver uses the latter—which only they have—to securely decrypt the message. Asymmetric key cryptography encrypts and decrypts messages using algorithms. These are based on various mathematical principles, such as multiplication or factorization—multiplying two big prime numbers to generate one massive, random number which is incredibly tricky to crack—or exponentiation and logarithms, which create exceptionally complex numbers that are nearly impossible to decrypt, such as in 256-bit encryption. There are different types of asymmetric key algorithms, such as: RSA: The first type of asymmetric cryptography to be created, RSA is the basis of digital signatures and key exchanges, among other things. The algorithm is based on the principle of factorization. Elliptic Curve Cryptography (ECC): Often found in smartphones and on cryptocurrency exchanges, ECC employs the algebraic structure of elliptic curves to build complex algorithms. Significantly, it does not require much storage memory or usage bandwidth, making it especially useful for electronic devices with limited computing power. Digital Signature Algorithm (DSA): Built on the principles of modular exponentiations, DSA is the gold standard for verifying electronic signatures and was created by the National Institute of Standards and Technologies. Identity-based Encryption (IBE): This unique algorithm negates the need for a message recip