Encryption in a Quantum World: Symmetric vs. Asymmetric

In 2023, researchers demonstrated a quantum computer’s ability to crack encryption algorithms previously thought unbreakable. This breakthrough underscored the imminent threat that quantum computing poses to digital security. Today, technologies that protect our most sensitive data—like banking information and personal records—are at risk. With quantum computing advancing rapidly, understanding encryption methods, and their vulnerabilities in this new era, is crucial. In this article, we’ll dive into the differences between symmetric and asymmetric encryption and explore how quantum computers could render them obsolete.

Symmetric Encryption: Fast and Efficient

Symmetric encryption, also known as secret-key encryption, uses a single key for both encryption and decryption. The simplicity of having one key makes this method fast and efficient, and is therefore an ideal choice for encrypting large datasets or real-time data streams. This type of encryption is typically used for data at rest, where large volumes of information—such as stored files and databases—need robust, continuous protection.

How Symmetric Encryption Works:

• The encryption process: Data is encrypted using a secret key, transforming the original information (plaintext) into an unreadable format (ciphertext).
• Key sharing: The same key must be shared between the sender and recipient to decrypt the data.
• The decryption process: The recipient uses the same key to decrypt the ciphertext, converting it back into readable plaintext.

Common Symmetric Algorithms:

• AES (Advanced Encryption Standard): AES is widely used for its speed and reliability, making it a top choice for secure data transmission and storage.
• Blowfish and 3DES: Though used less frequently now, these algorithms are still found in some legacy systems.

To learn more about AES, Blowfish and 3DES check out our article that highlights these encryption algorithms.

Pros and Cons of Symmetric Encryption:

• Pros: High-speed encryption and lower computational demands.
• Cons: Requires secure key exchange, as both parties need access to the same key. This makes key management challenging, especially over unsecured networks.

Asymmetric Encryption: Secure but Slower

Unlike symmetric encryption, asymmetric encryption (or public-key encryption) relies on a key pair—a public key for encryption and a private key for decryption. The public key can be openly shared, allowing anyone to encrypt data for the recipient, who alone can decrypt it with their private key. This structure makes asymmetric encryption highly effective for secure key exchange and identity verification, commonly used in internet security protocols and digital signatures.

How Asymmetric Encryption Works:

• The public and private keys: The public key is used to encrypt data, while the private key, known only to the owner, is used to decrypt it.
• The encryption process: Data is encrypted using the recipient’s public key, ensuring that only the holder of the matching private key can decrypt it.
• The decryption process: The private key decrypts the data, making it readable to the intended recipient.

Common Asymmetric Algorithms:

• RSA (Rivest–Shamir–Adleman): Widely used for secure email and web communications.
• ECC (Elliptic Curve Cryptography): Known for its efficiency, ECC is especially useful in resource-constrained environments.

Pros and Cons of Asymmetric Encryption:

• Pros: Allows secure communication without requiring a pre-shared key and is scalable in multi-user environments.
• Cons: Slower and more computationally demanding, which can hinder performance in real-time applications.

Comparing Symmetric and Asymmetric Encryption

Each type of encryption has unique advantages. See the chart below for a more direct comparison:

Hybrid Encryption: Combining the Best of Both

Hybrid encryption techniques leverage both methods, using asymmetric encryption to securely exchange a symmetric key, which then encrypts the actual data. This hybrid approach is common in protocols like TLS/SSL. TLS/SSL initially uses asymmetric encryption to establish a secure connection between client and server. Once the connection is established, symmetric encryption is used for the actual data transfer, ensuring both speed and security.

Quantum Computing’s Impact on Encryption

With the rise of quantum computing, encryption faces unprecedented challenges. Quantum computers are capable of processing vast amounts of data and can solve complex mathematical problems exponentially faster than classical computers. That enormous gain in speed poses a potential threat to current encryption techniques because quantum computers may have the ability to break the cryptographic algorithms in use today.

In particular, asymmetric encryption algorithms like RSA and ECC rely on the difficulty of factoring large numbers and solving discrete logarithm problems—tasks that quantum computers could solve efficiently using Shor’s algorithm. This means that if sufficiently advanced quantum computers become available, they could potentially decrypt data that is currently protected by these methods, exposing sensitive information.

Symmetric encryption, on the other hand, is less vulnerable to quantum threats. While quantum algorithms like Grover’s algorithm could reduce the effective security of symmetric encryption, it would still be significantly harder to break than asymmetric encryption. For example, the key size of AES-256 would only be halved in strength against quantum attacks, meaning AES-256 would remain highly secure even as quantum computing advances.

Preparing for the Quantum Era: Post-Quantum Cryptography

To address quantum threats, researchers are developing quantum-resistant cryptographic algorithms, often referred to as post-quantum cryptography (PQC). These algorithms rely on mathematical problems that are believed to be resistant to quantum attacks. Techniques like lattice-based and hash-based cryptography are being explored to develop secure and efficient encryption for a quantum-capable world.

Encryption solutions using AES-256 are currently considered quantum-resistant. By the end of 2025, encryption solutions will transition to PQC-compliant algorithms, ensuring robust defense against quantum threats. This shift will be included in system maintenance, though additional licensing costs related to PQC algorithms will be invoiced to the customer.

NIST’s Role in Defining Post-Quantum Standards

In August 2024, the National Institute of Standards and Technology (NIST) finalized three post-quantum cryptography standards, marking a milestone in the journey to a quantum-secure world. NIST’s PQC standards will serve as the foundation for safeguarding digital communications and data storage. By 2030, NIST aims to implement these standards broadly across the digital ecosystem, preparing industries for quantum-resistant encryption at scale.

This development underscores the need for encryption solutions to stay aligned with NIST’s evolving standards. For example, by 2025, some providers will offer customers PQC-ready options, allowing for the smooth transition to these standards as part of regular system maintenance. This approach minimizes disruptions and allows for a seamless upgrade to PQC, strengthening defenses without requiring costly overhauls.

Symmetric Encryption’s Quantum Advantage

Interestingly, symmetric encryption is less vulnerable to quantum computing. Quantum attacks like Grover’s algorithm can reduce the effective key size, but AES-256, for example, remains strong and viable even with this reduced security margin. As a result, symmetric encryption could play an even larger role in future encryption strategies, providing a quantum-resistant option for data at rest and other applications where efficiency is essential.

Encryptionizer and Quantum-Proof Symmetric Security

NetLib Security’s Encryptionizer is designed specifically for secure data at rest protection, utilizing AES-256 symmetric encryption, which is currently regarded as quantum-resistant. Unlike PQC, which focuses on protecting digital communications with public/private key pairs, Encryptionizer secures data stored in files without requiring network transport or digital certificates. Should AES-256 ever require quantum-resistance upgrades, customers on active support plans will have access to these enhancements as part of routine updates. Our primary PQC focus remains on digital signing to ensure the authenticity of program modules and drivers, in close collaboration with our signing partners.

Balancing Security and Performance in a Quantum Future

As cybersecurity threats grow more sophisticated, understanding the right encryption approach is critical. Symmetric encryption is ideal for large datasets and data at rest due to its speed and efficiency. Asymmetric encryption excels in key exchange and identity verification but will need to evolve with quantum computing advances.

The most secure strategies will likely involve both methods, with a focus on quantum-resistant algorithms. Staying informed and proactive ensures continued data protection in a rapidly evolving digital landscape.

About NetLib Security

NetLib Security has spent the past 20+ years developing a powerful, patented solution that starts by setting up a formidable offense for every environment where your data resides: physical, virtual and cloud. Our platform simplifies the process while ensuring high levels of security.

Simplify your data security needs. Encryptionizer is easy to deploy. It is a cost-effective way to proactively and transparently protect your sensitive data that allows you to quickly and confidently meet your security requirements. With budget considerations in mind, we have designed an affordable data security platform that protects, manages, and defends your data, while responding to the ever changing compliance requirements.

Data breaches are expensive. Security does not have to be.

NetLib Security works with government agencies, healthcare organizations, small to large enterprises, financial services, credit card processors, distributors, and resellers to provide a flexible data security solution that meets their evolving needs. To learn more or request a free evaluation visit us at www.netlibsecurity.com.