Cryptography in the Quantum Age: Do Quantum Computers Threaten Internet Security?

تمیم
August 20, 2026

Information security is one of the fundamental pillars of the digital world. Every day, billions of financial transactions, personal messages, medical records, and organizational data are transmitted over the internet, and all of them rely on cryptography technology. Without cryptographic algorithms, it would be impossible to maintain data confidentiality or authenticate users.

In recent decades, cryptographic algorithms have been able to largely guarantee the security of communications. However, the emergence of quantum computers has changed this equation. Many experts believe that in the future, the processing power of these computers could seriously challenge some common cryptographic methods. For this reason, understanding the current structure of cryptography and preparing for quantum-resistant technologies is becoming increasingly important.

Symmetric Encryption: Fast but Dependent on Key Management

One of the most common methods for protecting information is Symmetric Encryption. In this method, the sender and receiver use a shared key to encrypt and decrypt information.

The main advantage of this method is its high speed and low consumption of processing resources. For this reason, a large volume of data transmitted over the internet today is encrypted using symmetric algorithms.

One of the most well-known standards in this field is the Advanced Encryption Standard (AES), which was introduced as the U.S. encryption standard in 2001 and is now used in banking, cloud services, Virtual Private Networks (VPNs), storage systems, and many security devices.

Despite the high security of AES, there is a significant challenge: how to securely exchange the encryption key between the two parties?

Asymmetric Encryption: A Solution for Secure Key Exchange

To solve the key exchange problem, Asymmetric Encryption is used.

In this method, each user has two keys:

A Public Key, which can be shared with others.
A Private Key, which remains only with the owner.

When someone wants to send confidential information, they encrypt it with the recipient’s public key. Then, only the corresponding private key can decrypt the data.

This structure ensures that the private key never leaves the owner’s device, enhancing the security of the communication.

For this reason, many internet protocols like TLS, which provide website security, use a combination of asymmetric and symmetric encryption. Initially, asymmetric encryption is used for secure key exchange, and then the rest of the communication continues using faster symmetric algorithms.

Why is Asymmetric Encryption Secure?

The security of many asymmetric algorithms is based on mathematical problems that are very time-consuming for classical computers to solve.

For example, in some algorithms, security depends on the difficulty of factoring very large numbers into their prime factors. In others, calculating the discrete logarithm is considered the basis of security.

Although performing these calculations is theoretically possible, it could take millions or even billions of years for today’s computers. This characteristic has made these algorithms reliable for many years.

The Arrival of Quantum Computers: The Beginning of a Transformation

Quantum computers, unlike conventional computers that process information as bits of 0s and 1s, use Qubits.

Due to properties like Superposition and Entanglement, these computers can solve certain specific problems at speeds far exceeding classical computers.

Although large-scale, widely deployable quantum computers are not yet available, advances in recent years show that this technology is developing at a significant pace.

Shor’s Algorithm: Why Are Security Experts Concerned?

In 1994, American mathematician Peter Shor introduced an algorithm that showed a powerful quantum computer could solve the problem of factoring large numbers and calculating discrete logarithms much faster than classical computers.

This is highly significant because algorithms like RSA and ECC are precisely designed based on these same mathematical problems.

If sufficiently powerful quantum computers are achieved, many of these algorithms will no longer have their former security, and private keys could be derived in a much shorter time than before.

Is Symmetric Encryption Also at Risk?

The threat of quantum computers is not limited to asymmetric encryption, but the situation for symmetric encryption is different.

Some quantum algorithms could speed up Brute Force attacks, but there is a simpler solution in this area: increasing the length of encryption keys.

For example, using 256-bit keys in the AES algorithm can maintain a very high level of security even against future advancements.

Consequently, the main concern of the cybersecurity community is focused above all on asymmetric algorithms, which play a fundamental role in key exchange and authentication.

Why Should We Prepare for the Future Today?

One of the most important concerns for security experts is a phenomenon known as “Harvest Now, Decrypt Later.”

In this scenario, attackers might collect and store encrypted data today, even if they cannot currently decrypt it. As quantum computers advance in the future, this information could be decrypted.

This issue is particularly important for information with long-term value, such as government documents, medical records, military information, or corporate intellectual property. For this reason, many organizations have already begun planning for a migration to quantum-resistant technologies.

Conclusion

Quantum computers have not yet replaced classical computers, but their trend of progress shows that the cybersecurity industry must prepare for the future starting today. Algorithms that have been the mainstay of internet security for years may no longer meet security needs in the coming decades.

In this regard, researchers and standards organizations worldwide are working on developing a new generation of cryptographic technologies so that digital infrastructures can remain resilient against the threats of the quantum age.