Quantum Safe Algorithms: 3 Proven Ways to Save Your Data from Quantum Computers Threat

Key Points

• Quantum computers may soon break current encryption methods, posing a significant threat to data security.
• The “harvest now, decrypt later” strategy means adversaries could steal encrypted data today and decrypt it in the future.
• Post-quantum cryptography (PQC) offers solutions to protect data against quantum attacks, with new standards already available.
• Organizations should start preparing now to ensure long-term data security, as the transition to PQC is complex and time-consuming.

Introduction

Imagine a world where the locks protecting your most sensitive information—bank accounts, medical records, or even national secrets—can be picked in seconds. This is the potential future with quantum computers, machines that harness the strange rules of quantum mechanics to perform calculations at unprecedented speeds. While they promise breakthroughs in fields like medicine and logistics, they also threaten the security of our digital world by potentially breaking the encryption we rely on daily.

The concept of “harvest now, decrypt later” is particularly alarming. It suggests that adversaries could steal encrypted data today and decrypt it later when quantum computers are powerful enough. This makes it critical to act now to protect data that needs to remain secure for years to come. In this article, we’ll explore how quantum computers work, why they threaten current cryptography, and the steps we can take to safeguard our data using post-quantum cryptography (PQC).

Understanding Quantum Computers

To understand the threat, we first need to grasp what makes quantum computers different from the classical computers we use today. Classical computers process information using bits, which are either 0 or 1. Quantum computers, however, use qubits, which can be 0, 1, or both simultaneously due to a property called superposition. This allows quantum computers to explore multiple solutions at once, making them incredibly powerful for specific tasks.

Another key property is entanglement, where qubits become linked so that the state of one affects the other, even across vast distances. This enables quantum computers to perform complex calculations more efficiently than classical computers.

Analogy: Think of a classical computer as a librarian searching for a book by checking each shelf one by one. A quantum computer is like having multiple librarians searching all shelves simultaneously, finding the book much faster. This ability makes quantum computers excel at tasks like searching large datasets or factoring large numbers, which are critical to cryptography.

As of 2025, quantum computers are advancing rapidly, with systems like IBM’s planned record-breaking qubit machine and Microsoft’s Majorana 1 processor. However, they are not yet powerful enough to break current encryption, which requires millions of qubits. For example, breaking a 2048-bit RSA key might need around 20 million qubits, while current systems have hundreds or thousands.

The Cryptographic Threat

Our current cryptographic systems fall into two categories: symmetric and asymmetric cryptography.

• Symmetric Cryptography: Uses a single key for both encryption and decryption. The Advanced Encryption Standard (AES) is a common example, with key sizes like 128 or 256 bits. Its security relies on the key being secret and long enough to resist brute-force attacks.
• Asymmetric Cryptography: Uses a pair of keys—a public key for encryption and a private key for decryption. RSA, named after its creators Rivest, Shamir, and Adleman, relies on the difficulty of factoring large numbers into their prime factors.

Quantum computers threaten both types, but in different ways:

• Grover’s Algorithm: For symmetric cryptography, this algorithm can search through possible keys more efficiently, effectively halving the key’s strength. For example, a 128-bit AES key offers only 64 bits of security against a quantum attack. Doubling the key size to 256 bits can restore security.
• Shor’s Algorithm: For asymmetric cryptography, this algorithm can factor large numbers exponentially faster than classical computers. For instance, factoring a 2048-bit RSA key, which would take classical computers longer than the universe’s age, could be done in hours or minutes by a quantum computer with sufficient qubits.

Example: Consider the number 21. Its prime factors are 3 and 7, which is easy to compute. But for a 2048-bit number (hundreds of digits), factoring is nearly impossible for classical computers. Shor’s algorithm makes this task feasible for quantum computers, breaking RSA and similar algorithms like elliptic curve cryptography (ECC).

The “Harvest Now, Decrypt Later” Scenario

The “harvest now, decrypt later” strategy is a significant concern. Adversaries could be collecting encrypted data today—such as emails, financial transactions, or government secrets—with the intent to decrypt it later when quantum computers are powerful enough. This is particularly risky for data that needs long-term protection, such as:

• Medical Records: Patient data that must remain confidential for decades.
• Financial Information: Bank transactions or credit card details that could be exploited if decrypted.
• Intellectual Property: Trade secrets that give companies a competitive edge.
• National Security: Classified information that could compromise safety if exposed.

Analogy: Imagine locking a diary with a padlock that’s secure today. If someone steals the diary now, they can’t read it. But if a master lock-picking tool is invented in the future, they could unlock it and read your secrets. Similarly, encrypted data stolen today could be decrypted in the future, making it critical to act now.

The exact timeline for when quantum computers will break current encryption is uncertain, with estimates ranging from 5 to 15 years. However, the risk of data being harvested now means organizations cannot afford to wait.

Quantum Safe Algorithms: Post-Quantum Cryptography

To counter this threat, researchers have developed post-quantum cryptography (PQC), which includes algorithms designed to resist quantum attacks. These algorithms are based on mathematical problems believed to be hard for both classical and quantum computers.

The U.S. National Institute of Standards and Technology (NIST) has led a global effort to standardize PQC algorithms. In August 2024, NIST finalized three standards:

• FIPS 203 (CRYSTALS-KYBER): For key encapsulation, used to securely exchange keys.
• FIPS 204 (CRYSTALS-Dilithium): For digital signatures, ensuring authenticity.
• FIPS 205 (SPHINCS+): Another digital signature algorithm, based on hash functions.

Additionally, HQC was selected for standardization in March 2025. These algorithms rely on problems like:

• Lattice-based cryptography: Based on the difficulty of solving lattice problems.
• Hash-based cryptography: Uses hash functions for secure signatures.
• Code-based cryptography: Relies on error-correcting codes.
• Multivariate cryptography: Uses systems of multivariate polynomials.

Table: Comparison of Key Sizes (128-bit Security Level)

This table shows that PQC algorithms often require larger key sizes than current algorithms, which can impact performance and storage, especially for resource-constrained devices like IoT systems.

Preparing for the Quantum Future

Transitioning to PQC is a massive undertaking, especially for organizations with thousands of applications using cryptography. Achieving crypto agility—the ability to quickly switch algorithms—is essential to future-proof systems.

The preparation process involves three key steps:

• Discover:
  • Create a cryptographic inventory to identify all instances of encryption in systems, networks, and databases.
  • Use automated scanning tools to detect cryptographic implementations, as manual searches are prone to errors.
  • Develop a Cryptographic Bill of Materials (CBOM) to catalog algorithms and their vulnerabilities.
• Manage:
  • Define crypto policies that specify required encryption strengths and standards.
  • Prioritize updates based on data sensitivity, focusing on critical systems first.
  • Track progress to ensure the transition stays on schedule.
• Remediate:
  • Update systems to use PQC algorithms, starting with NIST-standardized ones.
  • For legacy systems, deploy crypto proxies that handle PQC on behalf of older applications, ensuring security over public networks.
  • Test PQC implementations for performance and compatibility to avoid disruptions.

Example: A major bank discovered over 4,000 applications using cryptography. Updating one application per day would take over 10 years, highlighting the need to start now and prioritize critical systems.

Practical Steps and Tools

Organizations can leverage various tools and services to facilitate the transition to PQC:

• Automated Scanning Tools: Tools like those from PQShield can scan codebases and networks to identify cryptographic implementations, streamlining the discovery process.
• PQC Libraries: Open-source libraries, such as OpenSSL, are beginning to support PQC algorithms, allowing developers to test and integrate them.
• Hardware Security Modules (HSMs): Companies like Entrust offer HSMs that support PQC algorithms, providing secure key management.
• Cloud Services: Providers like AWS are integrating PQC into their cloud offerings, enabling quantum-safe encryption for cloud-based applications.
• Consulting Services: Firms like Quantum Xchange offer expertise in quantum key distribution and PQC, helping organizations plan their transition.

Example: A company with a legacy application can deploy a crypto proxy to use PQC for communication with modern browsers, protecting data over public networks without modifying the backend.

Individuals can also take steps by ensuring their service providers—such as banks or email services—are adopting PQC. Staying informed about quantum computing developments can help individuals make informed decisions about their data security.

Conclusion

The rise of quantum computing is both a promise and a peril. While it offers transformative potential, it also threatens to undermine the encryption that protects our digital lives. The “harvest now, decrypt later” strategy underscores the urgency of preparing for a quantum future. By adopting post-quantum cryptography and achieving crypto agility, organizations can safeguard their data against future threats.

The transition is complex, but with NIST-standardized algorithms like CRYSTALS-KYBER, CRYSTALS-Dilithium, and SPHINCS+, and tools from companies like PQShield and Entrust, the path forward is clear. Starting now is critical to ensure data remains secure when quantum computers become powerful enough to break current encryption.

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