A group of hackers has broken 768-bit RSA encryption keys.

"An international team of mathematicians, computer scientists and cryptographers broke the key though NFS, or number field sieve, which allowed them to deduce two prime numbers that when multiplied together generated a number with 768 bits," writes The Register's Dan Goodin. "The discovery, which took about two-and-a-half years and hundreds of general-purpose computers, means RSA keys can no longer be counted on to encrypt or authenticate sensitive communications."

"More importantly, barring a breakthrough in NFS or some other form of mathematical factoring, it means it's only a matter of another decade or so until the next largest RSA key size, at 1024 bits, is similarly cracked," Goodin writes.