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Quantum Cryptography- Now To Be a Reality Soon

Why Quantum Cryptography is Important?

Users place enormous trust in banks and commercial enterprises to keep sensitive information such as credit card details, social security number etc. information safe while conducting online transactions. What if these enterprises can no longer guarantee the security of the private information, using current encryption methods? Cybercriminals are always trying to gain access to secure data, but when quantum computers come online, that information will be even more at risk of being hacked. In fact, hackers have always had head start as they have been collecting encrypted data, but needs significant computing ability to break the code. While decryption is difficult to do with conventional computing, relatively powerful quantum computer will enable breaking of the existing schemes. However, the twist comes when encryption is done using with quantum encryption, as decryption will not be straightforward.

Quantum Cryptography Definition

Quantum cryptography, also called quantum encryption, applies principles of quantum mechanics to encrypt messages in a way that no one outside of the intended recipient can decipher or read it. It takes advantage of “multiple states” and “no change theory” of quantum.

Performing these tasks requires a quantum computer, which has the immense computing power to encrypt and decrypt data. A quantum computer could quickly crack current cryptography schemes some of which are referred later in the article. Unlike mathematical encryption, quantum cryptography uses the principles of quantum mechanics to encrypt data and make it virtually “unhackable”.

Unlike mathematical encryption, quantum cryptography uses the principles of quantum mechanics to encrypt data and making it virtually unhackable.

How quantum cryptography works?

Quantum cryptography or quantum key distribution (QKD) uses a series of photons (light particles) to transmit data from one location to another over a fiber optic cable. By comparing measurements of the properties of a fraction of these photons, the two endpoints can determine the key value and whether it is safe to use. The steps are as follows:

  • The sender transmits photons through a filter (or polarizer), which randomly gives them one of four possible polarizations and bit designations: Vertical (One bit), Horizontal (Zero bit), 45 degree right (One bit), or 45 degree left (Zero bit)
  • The photons travel to a receiver, which uses two beam splitters (horizontal/vertical and diagonal) to “read” the polarization of each photon. The receiver does not know which beam splitter to use for each photon and has to guess which one to use
  • Once the stream of photons has been sent, the receiver inform the sender about the beam splitter used for each of the photons in the sequence they were sent. The sender then compares that information with the sequence of polarizers used to send the key. The photons that were read using the wrong beam splitter are discarded, and the resulting sequence of bits becomes the key

The photon’s state will change if it is read or copied by an eavesdropper and the endpoints will detect the change. In other words, a photon cannot be read, copied or forwarded without being detected.

Following are the list of commonly used encryption schemes

Triple Data Encryption Standard (DES) is a computerized cryptography where block cipher algorithms are applied three times to each data block. The key size is increased in Triple DES to ensure additional security through encryption capabilities. Each block contains 64 bits of data. Three keys are referred to as bundle keys with 56 bits per key.

RSA encryption is a public-key encryption technology developed by RSA Data Security. The RSA algorithm is based on the difficulty in factoring very large numbers. The RSA encryption algorithm uses prime factorization as the trap door for encryption. Deducing an RSA key, therefore, takes a huge amount of time and processing power. RSA is the standard encryption method for important data, including those transmitted over the Internet.

Blowfish encryption is a symmetric block cipher (a method that allows encrypting data in blocks) that can be used in place of Data Encryption Standard (DES) or International Data Encryption Algorithm (IDEA). It takes a key that varies in length from 32 to 448 bits. It works for both domestic and exportable use.

Twofish is related to the earlier block cipher Blowfish, which is a 64-bit clock cipher that uses a key length varying between 32 and 448 bits also developed by Bruce Schneir. Twofish is also related to Advanced Encryption Standard (AES), a 128-bit block cipher that the United States government adopted as it’s specification for the encryption of electronic data by the U.S. National Institute of Standards and Technology In 2001. While Twofish was a finalist to become the industry standard for encryption, it was beaten out by AES because of Twofish’s slower speed.

Advanced Encryption Standard (AES) is a cipher, meaning that it is a method or process used to change raw information (usually human readable) into something that cannot be read. This part of the process is known as encryption. The method uses a known external piece of information called “key” to uniquely change the data.

When will Quantum Cryptography become available?

The bigger question is about the availability of quantum computers and how much more time to realize quantum cryptography? There are significant engineering challenges to develop quantum computers that can take decades to solve. The technology is still in its infancy, Google has developed a machine with about 50 qubits and IBM is talking about 70 qubits.

Cracking today’s standard RSA encryption would take thousands of qubits. Adding those qubits is not easy because they are so fragile. Additionally, quantum computers today have extremely high error rates and require even more qubits for error correction. “I teach a class on quantum computing,” says University of Texas’s Brian R. La Cour. “Last semester, we had access to one of IBM’s 16-qubit machines. I was intending to do some projects with it to show some cool things you could do with a quantum computer.” That didn’t work out, he says. “The device was so noisy that if you did anything complicated enough to require 16 qubits, the result was pure garbage.”

Once that scalability problem is resolved, we will be well on our way to having usable quantum computers, he says, but it is impossible to put a timeframe on it. Brian R. La Cour guesses that we are probably decades away from the point at which quantum computers can be used to break today’s RSA encryption. There is plenty of time to upgrade to newer encryption algorithms.

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