According to documents provided by former NSA contractor Edward Snowden, the NSA has an effort to build “a cryptologically useful quantum computer” — a machine exponentially faster than classical computers. It is part of a $79.7 million research program titled “Penetrating Hard Targets.” Much of the work is hosted under classified contracts at a laboratory in College Park, Md.
A working quantum computer would open the door to easily breaking the strongest encryption tools in use today, including a standard known as RSA, named for the initials of its creators. RSA scrambles communications, making them unreadable to anyone but the intended recipient, without requiring the use of a shared password. It is commonly used in Web browsers to secure financial transactions and in encrypted e-mails. RSA is used because of the difficulty of factoring the product of two large prime numbers. Breaking the encryption involves finding those two numbers. This cannot be done in a reasonable amount of time on a classical computer.
In 2009, computer scientists using classical methods were able to discover the primes within a 768-bit number, but it took almost two years and hundreds of computers to factor it. The scientists estimated that it would take 1,000 times longer to break a 1,024-bit encryption key, which is commonly used for online transactions.
A large-scale quantum computer, however, could theoretically break a 1,024-bit encryption much faster. Some leading Internet companies are moving to 2,048-bit keys, but even those are thought to be vulnerable to rapid decryption with a quantum computer.
Quantum computers have many applications for today’s scientific community, including the creation of artificial intelligence. But the NSA fears the implications for national security.
There are quantum computing proof encryption schemes. It would mean changing the RSA algorithms for new quantum proof software and codes.