Data Encryption: What It Is, How It Works, and Best Practices

What is data encryption? 

Data encryption converts information into an unreadable format to protect it from unauthorized access. This process ensures that only those with the correct decryption key can interpret the data. It involves algorithms that transform plaintext into ciphertext. Encryption secures data across various systems, from personal devices to enterprise-level networks, enhancing privacy and security.

Encryption protects sensitive information such as financial records, personal details, and proprietary business data. By converting this information into an unintelligible format, encryption helps prevent data breaches and unauthorized access.

This is part of a series of articles about zero trust security.

How data encryption works 

Data encryption works by transforming readable data into ciphertext (unreadable data) using mathematical algorithms and encryption keys. This process ensures that only authorized parties with the appropriate decryption key can convert the ciphertext back to its original form. The encryption process typically involves the following steps:

1. Key generation: The encryption process begins with the creation of one or more encryption keys. In symmetric encryption, a single key is used for both encryption and decryption. In asymmetric encryption, a pair of keys—public and private—is generated, where the public key encrypts the data, and the private key decrypts it.
2. Encryption algorithm: The plaintext data is passed through an encryption algorithm, which scrambles it into ciphertext. This algorithm uses the encryption key to determine how the data is transformed. The strength of encryption depends on the complexity of the algorithm.
3. Ciphertext transmission or storage: The resulting ciphertext is unintelligible without the decryption key and so can be transmitted or stored.
4. Decryption: To revert the ciphertext back to its original form, the corresponding decryption key is applied to the encrypted data using a decryption algorithm. For symmetric encryption, the same key used to encrypt the data is applied. In asymmetric encryption, the private key corresponding to the public key is used.

Modern encryption systems enhance security with features like hashing for data integrity and initialization vectors to prevent pattern recognition. These features make encryption more resistant to attacks, such as brute force or cryptanalysis.

Common data encryption algorithms 

Symmetric encryption algorithms

Symmetric encryption uses the same key for both encryption and decryption. Organizations use symmetric encryption in scenarios where secure key exchange and storage is feasible:

• Advanced Encryption Standard (AES): AES is one of the most widely used symmetric encryption algorithms. It supports key sizes of 128, 192, and 256 bits, with larger keys providing greater security. AES is commonly used in applications like VPNs, file encryption, and secure communications.
• Data Encryption Standard (DES): Once a standard for data encryption, DES uses a 56-bit key. However, due to its vulnerability to brute-force attacks, it has largely been replaced by more secure algorithms like AES, and DES should never be used.
• Triple DES (3DES): This algorithm applies DES encryption three times to each data block, significantly increasing security. While more secure than DES, 3DES is slower and has been deprecated in favor of AES for most modern use cases.
• Blowfish and Twofish: Both algorithms are known for their flexibility and speed. Blowfish uses a variable key length from 32 to 448 bits and is often used in software applications like password management tools. Twofish, a successor to Blowfish, offers improved performance and supports up to 256-bit keys.

Symmetric encryption is suitable for securing database records, file systems, and encrypted storage in environments where key sharing is manageable.

Asymmetric encryption algorithms

Asymmetric encryption uses a pair of keys: a public key for encryption and a private key for decryption. This approach is commonly used in scenarios requiring digital signatures:

• RSA (Rivest-Shamir-Adleman): RSA provides strong security with key lengths typically starting at 2048 bits. RSA is used in applications like SSL/TLS for secure web browsing and email encryption.
• Elliptic Curve Cryptography (ECC): ECC is a modern asymmetric encryption technique offering the same security as RSA but with shorter key lengths, making it faster and more resource efficient. ECC is increasingly popular in mobile devices, IoT, and blockchain technology.
• Diffie-Hellman (DH): While not an encryption algorithm itself, DH is a key exchange method that enables two parties to securely establish a shared secret over an insecure channel. It is often combined with symmetric encryption algorithms for secure communications.
• Digital Signature Algorithm (DSA): DSA is primarily used for creating digital signatures, ensuring data authenticity and integrity. It is commonly used in government and compliance-based systems.

Asymmetric encryption is suitable for securing email communications, establishing SSL/TLS connections, and enabling digital signatures in electronic documents.

Data encryption in transit vs at rest 

Data encryption in transit

Data encryption in transit protects information as it moves through networks, protecting against interception and eavesdropping. TLS is a common protocol that encrypts data in transit, ensuring secure communication between clients and servers. Using asymmetric encryption during the initial handshake enables efficient encryption.

Encryption in transit is crucial where sensitive information is transmitted over public networks, such as the internet. Without it, data is vulnerable to interception by malicious actors. Ensuring encrypted connections, like using HTTPS for websites, is fundamental in maintaining data confidentiality during transmission.

Data encryption at rest

Data encryption at rest secures information stored in databases, servers, or any storage device, preventing unauthorized access. It protects data even if physical devices are compromised or stolen. By encrypting files, applications, or entire databases, sensitive information remains secure from attackers attempting to exploit unencrypted stored data.

Encryption at rest is critical for protecting stored data against both internal and external threats. It ensures compliance with regulatory requirements mandating the protection of personal data, such as GDPR or HIPAA. Implementing encryption mechanisms like full disk encryption or database encryption provides data protection in varied storage environments.

Applications of data encryption 

Data encryption is widely applied across various domains to ensure the confidentiality, integrity, and security of sensitive information. Key applications include:

• Secure online transactions: Encryption protects financial data, such as credit card information and payment details, during online transactions. Secure protocols like TLS ensure that data transmitted between users and payment gateways is safe from interception.
• Email security: Encrypted email services protect messages from unauthorized access, ensuring that sensitive communications remain confidential. Technologies like Pretty Good Privacy (PGP) provide encryption for email content and attachments.
• Cloud storage security: Data stored in cloud environments is encrypted to prevent unauthorized access, whether during transmission to the cloud or while at rest. Many cloud providers offer end-to-end encryption to improve data protection.
• Virtual private networks (VPNs): VPNs use encryption to create secure tunnels for transmitting data over public networks. This ensures that users can access private networks securely and maintain their online privacy.
• Data protection in Internet of Things (IoT) devices: IoT devices often handle sensitive data, such as personal health information or home security footage. Encryption secures the data transmitted between devices and central systems, preventing unauthorized access.
• Healthcare data security: Compliance with regulations like HIPAA requires healthcare providers to encrypt patient data to ensure privacy. Encryption protects electronic health records (EHRs) and other sensitive medical information.
• Government and military communications: Highly sensitive communications in government and defense sectors rely on encryption to prevent espionage and data breaches. Secure encryption algorithms ensure national security data remains confidential.
• Authentication and access control: Encryption is integral to securing authentication systems, such as passwords and biometric data. Hashing and encryption methods protect credentials from unauthorized access or theft.
• Secure backup and archival: Data encryption ensures that backup files and archives remain secure even if storage devices are stolen or compromised. This is critical for disaster recovery and compliance with data retention policies.
• Protecting intellectual property: Organizations use encryption to secure intellectual property, such as proprietary software, designs, and trade secrets. This prevents unauthorized access to confidential information.

Best practices for data encryption 

Organizations should adopt the following practices to ensure the strongest possible data protection.

Use strong encryption standards

Algorithms like AES-256 (Advanced Encryption Standard with a 256-bit key) are widely regarded as the gold standard for symmetric encryption due to their resilience against brute force attacks. Similarly, RSA with a minimum key length of 2048 bits is recommended for asymmetric encryption.

It’s essential to avoid deprecated algorithms like DES (Data Encryption Standard) or RC4, which are now vulnerable to known exploits. For secure communication over networks, use protocols like TLS 1.3, which leverage modern encryption techniques and eliminate older, insecure ciphers. Regularly evaluate the encryption standards used and stay informed about emerging threats or advancements in cryptographic research. 

Implement key management best practices

Mismanagement of encryption keys can render even the strongest encryption meaningless. A well-structured key management policy includes secure generation, distribution, storage, and destruction of keys. Use hardware security modules (HSMs) or cloud-based key management services (KMS) to securely generate and store keys, ensuring they are isolated from application code.

Key rotation is a critical practice to minimize the impact of compromised keys. Rotate keys periodically and immediately if a breach is suspected. Implement access controls to ensure only authorized personnel or systems can handle sensitive keys, and log all key-related activities for audit purposes. A key recovery plan is essential to mitigate data loss in the event of a lost key.

Enable end-to-end encryption (E2EE)

E2EE ensures data is encrypted at its source and only decrypted at its intended destination. This approach prevents intermediaries, including service providers and network administrators, from accessing the data, even if they intercept it during transmission. E2EE is especially important for messaging platforms, cloud storage services, and file-sharing applications where sensitive information is exchanged.

For example, messaging apps like Signal and WhatsApp use E2EE to ensure that only the sender and recipient can read messages. To implement E2EE, ensure encryption keys are generated and stored on the end-user’s device, rather than centralized servers. For applications requiring high security, consider additional measures like forward secrecy, which generates new encryption keys for every session.

Use strong passwords and multi-factor authentication (MFA)

Encryption is only as strong as the mechanisms protecting access to it. Strong passwords should be at least 12–16 characters long, incorporating a mix of uppercase and lowercase letters, numbers, and special characters. Avoid using easily guessable information, such as birthdays or common words.

Incorporating MFA further improves security by requiring additional verification beyond a password. MFA methods include one-time passwords (OTPs), biometric authentication (like fingerprints or facial recognition), or physical security keys. These layers reduce the risk of unauthorized access, even if a password is compromised. 

Avoid hardcoding encryption keys

Hardcoding encryption keys in application code exposes sensitive keys to potential attackers. If an attacker gains access to the source code, they can easily retrieve the hardcoded keys, compromising the entire encryption system. Instead, use secure key storage solutions like environment variables, secure vaults (e.g., HashiCorp Vault), or cloud-based key management services to retrieve keys dynamically at runtime.

Separating keys from application logic ensures they remain protected even if the application code is breached. Regularly review application code to ensure there are no hardcoded keys and use automated tools to detect such vulnerabilities during development. 

Test for performance

Encryption can introduce computational overhead, particularly when processing large datasets or operating in resource-constrained environments like IoT devices. To ensure optimal performance, conduct regular testing to assess how encryption affects system responsiveness. Test under various conditions, including high user loads.

Select encryption algorithms that strike a balance between security and efficiency. For example, ECC (Elliptic Curve Cryptography) provides equivalent security to RSA but with smaller key sizes, making it more suitable for environments with limited computational power. Optimize encryption processes with hardware acceleration.

Simplifying encryption for developers

Encryption is critical for securing data, but managing keys, algorithms, and evolving security standards can be a constant drain on development resources. Instead of getting stuck maintaining cryptographic systems, developers need solutions that streamline encryption without sacrificing security or control.

Frontegg’s CIAM platform reduces the burden of identity and security management with built-in encryption and compliance-ready authentication—so you can focus on building, not maintaining.

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