Can Quantum Computers Break Encryption

By Clint Brown

Security and Quantum Computing 

Imagine that you want to whisper a secret to your friend. If he (or she) is sitting next to you, you can share that secret with the snap of a finger. However, if your friend is miles away, it means that you need to get in touch with him or her over an internet-enabled digital device. Now, let’s be honest: You don’t know the number of people who can intercept that information along the line and read the message (secret). As you are well aware, if that piece of information gets into the wrong hands, then it is no longer a secret. 

Little wonder cybersecurity continues to be on the front burner in the tech milieu. Simply put, information shared over the internet is cryptographically concealed so it doesn’t get into the wrong hands. The moment you encrypt your message, you don’t have to worry that hackers and eavesdroppers will decrypt its content. To this end, companies deploy various encryption algorithms, such as RSA, Triple DES, AES, Blowfish, and Twofish. 

Ones and Zeros indicating information being encrypted. Posing the question Can Quantum Computers Break Encryption

Simplifying Cryptography 

Now, let’s help you understand this whole concept with a simple example. Assuming that Bob and Alice work for Company XYZ, but they are at two different locations that are miles apart. While Bob works at its Texas headquarters, Alice works from its Sydney office. Now, Bob wants to share a secret with Alice so that no eavesdropper can understand its content. Then, he encrypts the email and sends her this: 

Hi Alice,

How’s life over there in Sydney? 

I hear your marketing team is doing a great job? My team at Texas is proud of you! 

By the way, I think our CEO is stealing from our company, so he is being investigated for fraud.

Please don’t tell anyone about it because nobody knows yet. 

I will tell you more as the drama unfolds. 

Take care. 

Warmest regards,


If someone intercepts Bob’s email along the communication channel, he or she can’t understand it because it will appear like this: hgwyetsnsnvaUmo16d6dfsskuwtqpodm8r4e2n. Why is that? 

You see, in cryptography, keys are pieces of information or strings of numbers and letters in a file that help you to hide and/or unwrap data. The most common methods of cryptography are encryption and decryption. Also, there are two main types of encryption in widespread use today – symmetric and asymmetric encryption. While the same key is used for encryption and decryption in symmetric technique, two different keys are used for the same purpose in the asymmetric method. For the latter, the first is a public key (because it can be shared among recipients) and the other is a private key (because the owner keeps it close to his or her chest). The symmetric technique is faster. Hence, it is used for communication and storing data. On the other hand, the asymmetric technique is primarily used for key exchange, authentication, and signing messages, certificates, documents, etc. 

Using RSA to Protect Today’s Computer Networks  

RSA is one of the popular asymmetric techniques in the tech world. Keep in mind that RSA stands for Rivest Ronald Linn, Shamir Adi, and Adleman Leonard Max, which are the names of the developers. RSA is often used for protecting data systems over networks. With this technology, it is difficult for an unauthorized person to crack messages because it factors large prime numbers. The moment a sender encrypts the information with the RSA algorithm, it can only take a private key to “open” it. 

Let’s simplify how it works further by returning to the example above. Since Bob wants to send a private email to Alice using the RSA encryption, both Bob and Alice need to have the private and public keys. Now, Bob sends the email to Alice and encrypts it with her public key. The public key is like her address (better still, it is her digital destination), so sending the email to it means that the email is delivered to the correct address. Upon getting to Alice, she decrypts it with her private key. If anyone intercepts the email along the communication channel, they cannot crack it. If Alice wants to reply to the email, she will encrypt her response in Bob’s public key. When it gets to Bob, he decrypts it with his private key. This way, they won’t have to worry that someone can intercept and read their little secret.   

Can Quantum Computers Break Encryption? 

Well, you will find the answer to that question intriguing. You know, given the architectural design of quantum computers, many cybersecurity experts worry that the next-gen technology could be a threat to the security of classical devices. You see, most hackers use trial and error to break into codes. For today’s conventional technology to crack cryptographic security, it requires a lot of hard work and time. For instance, in July 2002, a group of 30,000 people disclosed that it cracked a 64-bit key after working for over four and half years. If it was a 128-bit key, which is twice the key in question, that group would use the world’s fastest computer to achieve “a similar feat” in trillions of years. Note that 128-bit encryption is the most commonly used method today. 

However, when quantum computing goes into full commercialization, every conventional computer user who cares about cybercrimes will have a cause for concern. This is particularly because quantum computing comes with Grover’s algorithm. In simple English, Grover’s algorithm enables that generation of computers to speed up unstructured search problems. On top of that, quantum computing has what experts call the amplitude amplification trick, which allows the disruptive devices to obtain quadratic runtime improvement for numerous algorithms. Therefore, the combination of Grover’s algorithm and amplitude amplification trick will see these quantum devices speed things up way better than today’s digital devices. 

So, yes, the odds are high that quantum devices may undermine the security of today’s computers. However, today’s quantum technology cannot crack asymmetric encryption due to its complex prime number configuration for computing private values. For quantum devices to crack asymmetric cryptography, they must have a processing speed about 100,000 times more powerful and error rate 100 times better than those quantum devices that exist today. In a nutshell, asymmetric cryptography is difficult to break because it uses a long pair of keys like 2048 bits. Nevertheless, by applying Shor’s algorithm, quantum devices of 4096-bit key pairs should compromise today’s digital devices in a matter of hours.

Should We All Be Worried? 

No, there is no cause for alarm! First, quantum computers haven’t fully gone ubiquitous yet. More importantly, researchers are working round the clock to develop an encryption technique that can resist quantum devices’ code-breaking capabilities. According to the US National Institute of Standards and Technology (NIST), efforts are already underway to test the feasibility of 69 techniques that will withstand the threat, which quantum technology poses to today’s cybersecurity world. 

Tagged “post-quantum cryptography”, these 69 techniques in the works at the moment will ensure that hackers are kept at bay at all times. In fact, the NIST hopes to unveil its draft standard by 2024 or earlier. When the standard is fully implemented on web browsers and other internet applications and systems, you won’t have to lose your precious sleep over unauthorized persons stealing your confidential files or having access to your sensitive information.  

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