FREAK ("
Factoring RSA Export Keys") is a
security exploit of a cryptographic weakness in the
SSL/TLS protocols introduced decades earlier for compliance with
U.S. cryptography export regulations. These involved limiting exportable software to use only
public key pairs with
RSA moduli of 512 bits or less (so-called
RSA EXPORT keys), with the intention of allowing them to be broken easily by the
NSA, but not by other organizations with lesser computing resources. However, by the early 2010s, increases in computing power meant that they could be broken by anyone with access to relatively modest computing resources using the well-known
Number Field Sieve algorithm, using as little as $100 of
cloud computing services. Combined with the ability of a
man-in-the-middle to manipulate the initial cipher suite negotiation between the endpoints in the connection and the fact that the Finished hash only depended on the master secret, this meant that a man-in-the-middle, with only a modest amount of computation could break the security of any website that allowed the use of 512-bit export-grade keys. While the exploit was only discovered in 2015, its underlying vulnerabilities had been present for many years, dating back to the 1990s.