Quantum computing is advancing, encryption is facing a long-term challenge, and sensitive data could already be at risk. Should organizations panic about quantum security—or is there still time to prepare?

The Quantum Threat Is Closer Than You Think

Imagine spending years protecting your organization’s sensitive data with strong encryption, only to discover that a new generation of computers could eventually break the cryptographic algorithms you rely on.

It sounds like science fiction, but it is a real security concern.

Quantum computing has the potential to solve certain mathematical problems far more efficiently than classical computers. While today’s quantum computers cannot simply break all modern encryption, sufficiently powerful, fault-tolerant quantum computers could undermine some of the cryptographic systems that protect financial transactions, communications, digital identities, and sensitive information.

This raises an important question: Should we panic now, or wait until quantum computers become powerful enough to threaten today’s security systems?

The answer is neither. We should prepare now.

1. Understanding the Quantum Threat

Modern cybersecurity relies heavily on cryptography to protect information. Different cryptographic methods serve different purposes, and quantum computing does not affect them all equally.

Two major categories are particularly important.

Asymmetric cryptography

Asymmetric cryptography uses a public key and a private key. It supports technologies such as digital signatures, secure key establishment, digital certificates, and authentication.

Common examples include RSA and elliptic-curve cryptography.

A sufficiently powerful, fault-tolerant quantum computer running Shor’s algorithm could solve the mathematical problems underlying widely used RSA and elliptic-curve systems. This could compromise their security.

That would affect more than encrypted messages. Digital signatures, certificate infrastructures, software authentication, and secure connections could also require changes.

Symmetric cryptography

Symmetric cryptography uses the same secret key to encrypt and decrypt data. AES is a widely used example.

Quantum computing presents a different challenge here. Grover’s algorithm can theoretically speed up certain brute-force searches, reducing the effective security margin of a symmetric key.

However, this does not mean AES suddenly becomes useless. For example, AES-256 is generally considered to retain a substantial security margin against known quantum attacks.

The practical lesson is that quantum computing poses different risks to different cryptographic algorithms. A sensible security strategy must account for those differences.

2. The “Harvest Now, Decrypt Later” Problem

One of the most concerning aspects of the quantum threat is a strategy commonly called harvest now, decrypt later.

An attacker may collect encrypted information today, store it, and wait for future advances in quantum computing that could make the information easier to decrypt.

Consider an organization transmitting sensitive information over the internet. Even if its communications are properly encrypted today, an attacker who records those communications could retain them for years.

If the attacker eventually gains access to a sufficiently powerful quantum computer, some previously captured information could become readable—provided the encryption used was vulnerable and the attacker can obtain the required resources.

This creates a serious concern for information that must remain confidential for decades, including:

• Government and national security information.
• Medical records and sensitive personal information.
• Financial records and long-term commercial secrets.
• Intellectual property and proprietary research.
• Sensitive communications and identity information.

The risk depends on the value and lifetime of the data, the cryptographic algorithms protecting it, and the resources available to an attacker.

Organizations therefore need to consider not only whether their encryption is secure today, but whether it will remain secure for the required lifetime of their information.

3. When Will Quantum Computers Break Today’s Encryption?

There is no universally agreed date when a cryptographically relevant quantum computer will become available.

Building a machine capable of breaking widely deployed cryptography would require substantial advances in hardware, error correction, and large-scale fault-tolerant computation.

Nevertheless, organizations cannot safely assume that such a machine is decades away—or that it will arrive on a predictable schedule.

Security migrations take time. Large organizations may need to identify thousands of systems, update applications, replace cryptographic libraries, coordinate with vendors, and validate new implementations.

Waiting until the threat is imminent could leave too little time to complete that transition.

The key question is not simply, “When will quantum computers break encryption?”

It is also, “How long would it take us to replace the cryptography that protects our most sensitive information?”

4. Enter Post-Quantum Cryptography

The good news is that preparing for the quantum era does not require waiting for quantum computers to mature.

Post-quantum cryptography (PQC) refers to cryptographic algorithms designed to resist attacks from both classical and known quantum computing approaches.

Unlike quantum cryptography, PQC generally runs on conventional computers. Organizations can deploy it through updated software, protocols, and cryptographic libraries.

In 2024, the U.S. National Institute of Standards and Technology (NIST) finalized three foundational post-quantum cryptographic standards:

• FIPS 203 — ML-KEM: A key-encapsulation mechanism based on the Module-Lattice-Based Key-Encapsulation Mechanism, designed to establish shared secret keys.
• FIPS 204 — ML-DSA: A digital-signature standard based on the Module-Lattice-Based Digital Signature Algorithm.
• FIPS 205 — SLH-DSA: A stateless hash-based digital-signature standard.

These standards give organizations concrete options for beginning their transition.

ML-KEM helps establish shared secrets for encrypted communications. ML-DSA and SLH-DSA support digital signatures, which are used to authenticate software, documents, and other digital objects.

It is important to understand that PQC does not automatically secure an entire system. Implementations, key management, endpoint security, protocol configuration, and operational practices still matter.

5. What About Quantum Key Distribution?

Another technology attracting attention is Quantum Key Distribution (QKD).

QKD uses quantum-mechanical properties to help two endpoints establish shared secret keys. Certain QKD protocols can reveal evidence of eavesdropping on the quantum channel.

However, QKD is not a universal replacement for post-quantum cryptography.

QKD generally requires specialized equipment and a suitable quantum communication channel. It also requires authenticated classical communications, secure endpoints, and careful key management.

PQC, by contrast, can generally be implemented in existing digital infrastructure through software and protocol updates.

For many organizations, post-quantum cryptography is likely to be the more practical starting point. QKD may have a role in specialized environments with appropriate infrastructure and security requirements.

The right choice depends on the threat model, deployment costs, performance requirements, and the sensitivity of the information being protected.

6. What Now?

Learn how BridgeOne Group can help your organization define migration goals, and perform cryptography discovery.