The Cat and Mouse Game of Cryptography

MD5 is a hashing algorithm created in 1991 and still used by many applications for certain features. But MD5 is no longer recommended for many cases due to weaknesses discovered in the last few years, opening up some scary possibilities. At the end of this year, NIST standards for cryptography used by the federal government will no longer permit 160-bit SHA1 hashes or 1024-bit RSA signature keys, since concerns over the long-term security of these technologies are rising.

With cryptographers constantly working on new algorithms and breaking old algorithms, one may get nervous about whether the foundations of today’s secure transactions are really that secure. But despite the occasional ominous forecast of a cryptographic meltdown, you can remain fairly confident in encryption technology.

Just as we’re constantly finding new weaknesses in various approaches, we’re constantly finding new approaches that overcome various weaknesses. For instance, scientists are working to develop “quantum computers” that perform calculations in a completely different way than today’s electronics. These new machines would be powerful enough to crack several of the strongest algorithms currently in wide use. But just this week, several researchers demonstrated that a 30-year-old algorithm, using a different type of mathematical basis, would foil any known quantum attack. This approach has not been widely used due to large key sizes that would hinder performance, but computers are getting faster every year.

Cryptographers also work to maintain a gap between theoretical attacks and practical compromises. NIST does not wait for programs that can crack any key within seconds before deprecating an algorithm. Researchers are constantly working to build stronger systems, and often start recommending replacements when only the slightest cracks begin to show for a particular approach. Also, one type of weakness does not necessarily ruin every possible use of a given encryption method.

But while the mathematics behind today’s systems may be sound for the near future, strong encryption alone does not guarantee you security. In fact, most security problems come through either insecure implementations of a given approach or bad security practices built on top of strong algorithms. Keeping current with effective cryptography is important, but it’s only one part of an effective security strategy.