Quantum Computing and Encryption Breaking

Question

I read a while back that Quantum Computers can break most types of hashing and encryption in use today in a very short amount of time(I believe it was mere minutes). How is it p

Answer 1

First of all, quantum computing is still barely out of the theoretical stage. Lots of research is going on and a few experimental quantum cells and circuits, but a "quantum computer" does not yet exist.

Second, read the wikipedia article: http://en.wikipedia.org/wiki/Quantum_computer

In particular, "In general a quantum computer with n qubits can be in an arbitrary superposition of up to 2^n different states simultaneously (this compares to a normal computer that can only be in one of these 2^n states at any one time). "

What makes cryptography secure is the use of encryption keys that are very long numbers that would take a very, very long time to factor into their constituent primes, and the keys are sufficiently long enough that brute-force attempts to try every possible key value would also take too long to complete.

Since quantum computing can (theoretically) represent a lot of states in a small number of qubit cells, and operate on all of those states simultaneously, it seems there is the potential to use quantum computing to perform brute-force try-all-possible-key-values in a very short amount of time.

If such a thing is possible, it could be the end of cryptography as we know it.

Answer 2

Even more bizarr imo. is the Grover's algorithm. As input we get here an unsorted array of integers with arraylength = n. What is the expected runtime of an algorithm, that finds the min value of this array? Well classically we have at least to check every 1..n element of the array resulting in an expected runtime of n. Not so for quantum computers, on a quantum computer we can solve this in expected runtime of maximum root(n), this means we don't even have to check every element to find the guaranteed solution...

Answer 3

A quantum computer can implement Shor's algorithm which can quickly perform prime factorization. Encryption systems are build on the assumption that large primes can not be factored in a reasonable amount of time on a classical computer.

Answer 4

quantum computers etc all lies. I dont believe these science fiction magazines. in fact rsa system is based on two prime numbers and their multipilation. p1,p2 is huge primes p1xp2=N modulus. rsa system is like that choose a prime number..maybe small its E public key (p1-1)*(p2-1)=R find a D number that makes E*D=1 mod(R) we are sharing (E,N) data as public key publicly we are securely saving (D,N) as private.

To solve this Rsa system cracker need to find prime factors of N. *mass of the Universe is closer to 10^53 kg* electron mass is 9.10938291 × 10^-31 kilograms if we divide universe to electrons we can create 10^84 electrons. electrons has slower speeds than light. its move frequency can be 10^26 if anybody produces electron size parallel rsa prime factor finders from all universe mass. all universe can handle (10^84)*(10^26)= 10^110 numbers/per second.

rsa has limitles bits of alternative prime numbers. maybe 4096 bits 4096 bit rsa has 10^600 possible prime numbers to brute force. so your universe mass quantum solver need to make tests during 10^500 years.

rsa vs universe mass quantum computer 1 - 0

maybe quantum computer can break 64/128 bits passwords. because 128 bit password has 10^39 possible brute force nodes.