RSA (Rivest, Shamir and Adleman) is a cryptosystem widely used for secure data transmission. In such a cryptosystem, the security of the system is based on the
practical difficulty of factoring the product of two large prime numbers, the factoring problem. For instance, RSA-768, the largest number to be factored to date, had 232 decimal digits and was factored over multiple years ending in 2009, using the equivalent of almost 2000 years of computing on a single 2.2 GHz AMD Opteron processor with 2GB RAM.2! Read more about the RSA crytosystem and the RSA factoring challenge here.
Why should we care?!! The threat of quantum computers to this cryptosystem is real, a quantum algorithm for factoring a 300 decimal digit number needs only 5x 10^10 steps, or with gigahertz speed less than 17 minutes! With a terahertz speed, it takes less than a second! This will force the world to change its infrastructure when it comes to sensitive data transmission. If you want to learn more about quantum computing, read here.
