The future of cryptography
Today I learned about quantum cryptography, the use of quantum mechanics to perform cryptographic functions.
One of the most useful applications of quantum mechanics in cryptography is quantum key distribution, a method of distributing keys between two parties without a third party intercepting it. The nature of quantum communication means that if a third party tries to listen, discrepancies will arise. This has great potential for sending private messages, because if discrepancies arise, then the 2 parties will know that someone is eavesdropping.
However, quantum mechanics can also be used to improve cryptanalysis. For example, Shor’s algorithm, designed specifically for quantum computers, can factor extremely large numbers in polynomial time, which is a large boost from the factorial time it takes with traditional computing. Since modern cryptography involves multiplying large numbers, being able to factor so quickly will obviously be an advantage when trying to crack these ciphers.
