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What is Cryptography? Definition, Importance, Types | Fortinet Skip to content Skip to navigation Skip to footer CyberGlossary › Cybersecurity › What Is Cryptography? What Is Cryptography? Discover the types of cryptography and how to minimize the potential risks it poses. 2026 THREAT LANDSCAPE REPORT Definition Types Key Attacks Minimize Risks FAQs Definition Definition Types Key Attacks Minimize Risks FAQs Cryptography Definition Cryptography is the process of hiding or coding information so that only the person a message was intended for can read it. The art of cryptography has been used to code messages for thousands of years and continues to be used in bank cards, computer passwords, and ecommerce. Modern cryptography techniques include algorithms and ciphers that enable the encryption and decryption of information, such as 128-bit and 256-bit encryption keys. Modern ciphers , such as the Advanced Encryption Standard (AES), are considered virtually unbreakable—although emerging quantum algorithms are expected to challenge some traditional cryptographic models in the future. Organizations should begin planning for quantum readiness to protect these systems. A common cryptography definition is the practice of coding information to ensure only the person that a message was written for can read and process the information. This cybersecurity practice, also known as cryptology, combines various disciplines like computer science, engineering, and mathematics to create complex codes that hide the true meaning of a message. Cryptography can be traced all the way back to ancient Egyptian hieroglyphics but remains vital to securing communication and information in transit and preventing it from being read by untrusted parties. It uses algorithms and mathematical concepts to transform messages into difficult-to-decipher codes through techniques like cryptographic keys and digital signing to protect data privacy, credit card transactions, email, and web browsing. The Importance Of Cryptography Cryptography remains important to protecting data and users, ensuring confidentiality, and preventing cyber criminals from intercepting sensitive corporate information. Common uses and examples of cryptography include the following: Privacy and confidentiality Individuals and organizations use cryptography on a daily basis to protect their privacy and keep their conversations and data confidential. Cryptography ensures confidentiality by encrypting sent messages using an algorithm with a key only known to the sender and recipient. A common example of this is the messaging tool WhatsApp, which encrypts conversations between people to ensure they cannot be hacked or intercepted. Cryptography also secures browsing, such as with virtual private networks (VPNs), which use encrypted tunnels, asymmetric encryption, and public and private shared keys. It plays a similar role in cloud encryption , where data stored and transmitted in cloud environments is encoded to ensure it remains protected from unauthorized access. Authentication Integrity Similar to how cryptography can confirm the authenticity of a message, it can also prove the integrity of the information being sent and received. Cryptography ensures information is not altered while in storage or during transit between the sender and the intended recipient. For example, digital signatures can detect forgery or tampering in software distribution and financial transactions. Nonrepudiation Cryptography confirms accountability and responsibility from the sender of a message, which means they cannot later deny their intentions when they created or transmitted information. Digital signatures are a good example of this, as they ensure a sender cannot claim a message, contract, or document they created to be fraudulent. Furthermore, in email nonrepudiation, email tracking makes sure the sender cannot deny sending a message and a recipient cannot deny receiving it. Key exchange Key exchange is the method used to share cryptographic keys between a sender and their recipient. 2026 Global Threat Landscape Report Use this report to understand attacker tactics, assess your exposure, and prioritize action before the next exploit hits your environment. Download Now Types of Cryptographic Algorithms There are many types of cryptographic algorithms available. They vary in complexity and security, depending on the type of communication and the sensitivity of the information being shared. Secret Key Cryptography Secret key cryptography, also known as symmetric encryption, uses a single key to encrypt and decrypt a message. The sender encrypts the plaintext message using the key and sends it to the recipient who then uses the same key to decrypt it and unlock the original plaintext message. Stream ciphers Stream ciphers work on a single bit or byte at any time and constantly change the key using feedback mechanisms. A self-synchronizing stream cipher ensures the decryption process stays in sync with the encryption process by recognizing where it sits in the bit keystream. A synchronous stream cipher generates the keystream independently of the message stream and generates the same keystream function at both the sender and the receiver. Block ciphers Block ciphers encrypt one block of fixed-size data at a time. It will always encrypt a plaintext data block to the same ciphertext when the same key is used. A good example of this is the Feistel cipher, which uses elements of key expansion, permutation, and substitution to create vast confusion and diffusion in the cipher. The stages of encryption and decryption are similar if not identical, which means reversing the key reduces the code size and circuitry required for implementing the cipher in a piece of software or hardware. Public Key Cryptography Public key cryptography (PKC), or asymmetric cryptography, uses mathematical functions to create codes that are exceptionally difficult to crack. It enables people to communicate securely over a nonsecure communications channel without the need for a secret key. For example, proxy reencryption enables a proxy entity to reencrypt data from one public key to another without requiring access to the plaintext or private keys. A common PKC type is multiplication vs. factorization, which takes two large prime numbers and multiplies them to create a huge resulting number that makes deciphering difficult. Another form of PKC is exponentiation vs. logarithms such as 256-bit encryption, which increases protection to the point that even a computer capable of searching trillions of combinations per second cannot crack it. Generic forms of PKC use two keys that are related mathematically but do not enable either to be determined. Put simply, a sender can encrypt their plaintext message using their private key, then the recipient decrypts the ciphertext using the sender’s public key. Common PKC algorithms used for digital signatures and key exchanges include: RSA RSA was the first and remains the most common PKC implementation. The algorithm is named after its MIT mathematician developers, Ronald Rivest, Adi Shamir, and Leonard Adleman, and is used in data encryption, digital signatures, and key exchanges. It uses a large number that is the result of factoring two selected prime numbers. It is impossible for an attacker to work out the prime factors, which makes RSA especially secure. Eliptic Curve Cryptography (ECC) ECC is a PKC algorithm based on the use of elliptic curves in cryptography. It is designed for devices with limited computing power or memory to encrypt internet traffic. A common use of ECC is in embedded computers, smartphones, and cryptocurrency networks like bitcoin, which consumes around 10% of the storage space and bandwidth that RSA requires. Digital Signature Algorithm (DSA) DSA is a standard that enables digital signatures to be used in message authentication. It was introduced by the National Institute of Standards and Technology (NIST) in 1991 to ensure a better method for creating digital signatures. Identity-based Encryption (IBE) IBE is a PKC system that enables the public key to be calculated from unique information based on the user’s identity, such as their email address. A trusted third party or private key generator then uses a cryptographic algorithm to calculate a corresponding private key. This enables users to create their own private keys without worrying about distributing public keys. Public Key Cryptography Standards (PKCS) All PKC algorithms and usage are governed by a set of standards and guidelines designed by RSA Data Security. These are as follows: PKCS #1 or RFC 8017: RSA Cryptography Standard PKCS #3: Diffie-Hellman Key Agreement Standard PKCS #5 and PKCS #5 v2.1 or RFC 8018: Password-Based Cryptography Standard PKCS #6: Extended-Certificate Syntax Standard (being replaced by X.509v3) PKCS #7 or RFC 2315: Cryptographic Message Syntax Standard PKCS #8 or RFC 5958: Private Key Information Syntax Standard PKCS #9 or RFC 2985: Selected Attribute Types PKCS #10 or RFC 2986: Certification Request Syntax Standard PKCS #11: Cryptographic Token Interface Standard PKCS #12 or RFC 7292: Personal Information Exchange Syntax Standard PKCS #13: Elliptic Curve Cryptography Standard PKCS #14: Pseudorandom Number Generation Standard PKCS #15: Cryptographic Token Information Format Standard Diffie-Hellman and Key Exchange Algorithm (KEA) The Diffie-Hellman algorithm was devised in 1976 by Stanford University professor Martin Hellman and his graduate student Whitfield Diffie, who are considered to be responsible for introducing PKC as a concept. It is used for secret key exchanges and requires two people to agree on a large prime number. KEA is a variation of the Diffie-Hellman algorithm and was proposed as a method for key exchange in the NIST/National Security Agency’s (NSA) Capstone project, which developed cryptography standards for public and government use. Click to See Larger Image Ha