Encryption Definition - What Is Encryption and How Does It Work?

May 27, 2024

Encryption is the fundamental technique used to secure digital information by converting it into a coded format that is unreadable to unauthorized users. This process ensures that sensitive data, whether stored or transmitted, remains protected from potential threats and unauthorized access.

what is encryption

What Is Encryption?

Encryption is the process of converting plaintext, which is readable and understandable data, into ciphertext, an encoded format that appears meaningless without the proper decryption key. This transformation ensures that only authorized individuals with the correct decryption key can access and interpret the original information.

Encryption employs complex algorithms to encode data, making it an essential tool for protecting sensitive information from unauthorized access, theft, and tampering. It is a cornerstone of digital security, used extensively in various domains such as secure communications, data storage, online transactions, and protecting personal and confidential information. By ensuring that data remains confidential and intact during storage or transmission, encryption upholds privacy and data integrity, making it a critical component in the modern digital landscape.

How Does Encryption Work?

Encryption works by converting readable data (plaintext) into an unreadable format (ciphertext) using mathematical algorithms and a specific encryption key. Here’s a detailed explanation of how encryption functions:

  1. Encryption algorithm. An encryption algorithm is a set of mathematical procedures used to transform plaintext into ciphertext. Common algorithms include Advanced Encryption Standard (AES), Rivest-Shamir-Adleman (RSA), and Data Encryption Standard (DES). Each algorithm has its own method of creating the encoded output from the input data.
  2. Encryption key. An encryption key is a piece of information, often a string of characters, used by the algorithm to perform the encryption process. The key ensures that the ciphertext can only be decrypted by someone who has the corresponding decryption key. The strength of the encryption largely depends on the key length and complexity.
  3. Plaintext to ciphertext. When data needs to be encrypted, the plaintext is processed by the encryption algorithm using the encryption key. This process scrambles the data into ciphertext, making it unreadable to anyone who does not have the decryption key.
  4. Transmission or storage. The ciphertext can be safely transmitted over networks or stored in databases. Since it is unreadable without the decryption key, even if intercepted or accessed by unauthorized individuals, the information remains protected.
  5. Decryption process. For the original data to be accessed, the ciphertext must be processed through a decryption algorithm using the corresponding decryption key. This reverses the encryption process, converting the ciphertext back into plaintext. The decryption key is usually kept secure and only shared with authorized parties.

Encryption Types

Encryption is a vital component of data security, ensuring that information remains confidential and protected from unauthorized access. There are two primary types of encryption methods: symmetric and asymmetric encryption. Each method has its unique characteristics, use cases, and advantages.

Symmetric Encryption

Symmetric encryption, also known as secret-key or private-key encryption, involves using the same key for both encryption and decryption. This key must be kept secret and shared only with authorized parties.

The simplicity and efficiency of symmetric encryption make it suitable for encrypting large amounts of data quickly. However, its main challenge lies in securely sharing the key between the parties involved. For this reason, symmetric encryption is often used in scenarios where secure key exchange can be ensured, such as within closed systems or for encrypting data at rest.

Common symmetric encryption algorithms include Advanced Encryption Standard (AES) and Data Encryption Standard (DES).

Asymmetric Encryption

Asymmetric encryption, also known as public-key encryption, utilizes a pair of keys: a public key for encryption and a private key for decryption. The public key can be freely distributed, allowing anyone to encrypt data intended for the key owner, while the private key is kept secure and used only by the owner to decrypt the data. This method overcomes the key distribution problem inherent in symmetric encryption.

Asymmetric encryption is computationally more intensive and slower than symmetric encryption, making it less suitable for encrypting large amounts of data. However, it excels in securing key exchanges and protecting data in transit.  

Common asymmetric encryption algorithms include Rivest-Shamir-Adleman (RSA) and Elliptic Curve Cryptography (ECC).

Common Encryption Algorithms

Encryption algorithms are the backbone of data security, transforming readable information into encoded formats that protect against unauthorized access. Here are explanations of some common encryption algorithms.

Advanced Encryption Standard (AES)

AES is a symmetric encryption algorithm widely regarded for its efficiency and security. Established by the U.S. National Institute of Standards and Technology (NIST), AES uses key sizes of 128, 192, or 256 bits, making it robust against brute force attacks. Its speed and versatility make it a popular choice for encrypting sensitive data in various applications, including secure communications, financial transactions, and data storage.

Rivest-Shamir-Adleman (RSA)

RSA is an asymmetric encryption algorithm that relies on the mathematical difficulty of factoring large prime numbers. It uses a pair of keys—a public key for encryption and a private key for decryption. RSA is widely used for securing sensitive data transmitted over the internet, such as in SSL/TLS protocols for secure web browsing, email encryption, and digital signatures. Despite being slower than symmetric algorithms, RSA's strength lies in its ability to securely exchange keys and authenticate data.

Data Encryption Standard (DES)

DES is a symmetric key algorithm that was once the standard for encryption. It uses a 56-bit key, making it relatively fast in terms of computational requirements. However, its shorter key length makes it vulnerable to brute force attacks, leading to its gradual replacement by more secure algorithms like AES. DES is still used in some legacy systems, but it is largely considered obsolete for modern encryption needs.

Elliptic Curve Cryptography (ECC)

ECC is an asymmetric encryption algorithm that offers strong security with shorter key lengths compared to RSA. It leverages the properties of elliptic curves over finite fields, providing security with significantly reduced computational overhead. Due to its efficiency and robustness, ECC is favored in environments with limited processing power and bandwidth, such as mobile and IoT devices.

Triple DES (3DES)

Triple DES is an enhancement of the original DES algorithm, applying the DES cipher three times to each data block. This method increases the effective key length to 168 bits, increasing security. While more secure than DES, 3DES is slower and less efficient than newer algorithms like AES. It remains in use for certain applications that require compatibility with legacy systems while still needing advanced security.

Encryption Advantages and Disadvantages

Encryption is a powerful tool for protecting data, ensuring confidentiality, and securing communications. However, like any technology, it has its advantages and disadvantages. Understanding both the benefits and limitations of encryption helps in effectively implementing it.


Encryption offers numerous advantages that make it an essential component of modern data security:

  • Confidentiality. Encryption ensures that data remains confidential by converting it into an unreadable format that can only be accessed by authorized individuals with the correct decryption key. This protects sensitive information from unauthorized access and breaches.
  • Data integrity. Encryption helps maintain the integrity of data by preventing unauthorized modifications. Encrypted data can be checked for alterations, ensuring that it has not been tampered with during transmission or storage.
  • Security in transit. Encryption secures data during transmission over networks, protecting it from interception and eavesdropping. This is crucial for safeguarding communications, online transactions, and data exchanges between systems.
  • Compliance with regulations. Many industries are subject to regulations that mandate the protection of sensitive information. Encryption helps organizations comply with laws and standards, such as GDPR, HIPAA, and PCI DSS, and avoid legal and financial penalties.
  • Authentication. Encryption is used in conjunction with digital signatures and certificates to authenticate the identity of users and systems. These mechanisms help to ensure that communication and data exchanges are legitimate by preventing impersonation and unauthorized access.
  • Enhanced trust. By implementing strong encryption, organizations demonstrate a commitment to protecting data and privacy and build trust with customers and partners.
  • Protection against data breaches. Encryption adds an extra layer of security that protects data even if physical devices or systems are compromised. Encrypted data remains inaccessible to unauthorized users, reducing the impact of data breaches.


Here are the disadvantages of encryption:

  • Performance impact. Encryption algorithms, especially strong ones like AES and RSA, can be computationally intensive, leading to slower processing times. This performance overhead is particularly noticeable in resource-constrained environments, such as on mobile or IoT devices, where processing power and battery life are limited.
  • Key management complexity. Effective encryption relies heavily on secure key management. Generating, distributing, storing, and rotating encryption keys can be complex and challenging. Poor encryption key management practices compromise the security of data, potentially leading to unauthorized access.
  • Data recovery challenges. If encryption keys are lost or forgotten, the encrypted data becomes inaccessible, potentially resulting in data loss. Unlike other security measures, encryption does not offer an easy way to recover data without the proper decryption key. For this reason, it is vital to implement robust key management and backup strategies.
  • Implementation errors. Incorrect implementation of encryption algorithms introduces vulnerabilities. Issues such as weak keys, improper use of algorithms, or flawed integration undermine the effectiveness of encryption, making the data susceptible to attacks. Ensuring correct implementation requires expertise and thorough testing.
  • Compliance and legal issues. While encryption enhances data security, it can also create a potential conflict between privacy and regulatory requirements. Encrypted data can hinder legal investigations and compliance audits if proper access mechanisms or backdoors are not in place.
  • Usability concerns. Encryption complicates data access and sharing processes. Users need to manage encryption keys and understand the encryption mechanisms, which can be cumbersome and may lead to user errors or resistance to adoption. Balancing security with usability is crucial to ensure effective implementation.

Anastazija is an experienced content writer with knowledge and passion for cloud computing, information technology, and online security. At phoenixNAP, she focuses on answering burning questions about ensuring data robustness and security for all participants in the digital landscape.