Digital certificates, and therefore the security of network communication, rely on both cryptographic hash functions and the cipher algorithms used for encrypting and decrypting data. They are crucial for two stages of security. First, for the user to verify the identity of the web server before giving up their login and password, and therefore access to all their information, banks accounts and so on. Second, for the server and client hosts to negotiate a session key used to encrypt all network traffic and protect data confidentiality.
The technology has stayed the same for quite a while. U.S. NIST is recommending that longer RSA keys be used by the beginning of 2014, but that’s a change in scale, not method.
There is very good news: New technology is coming!
Symantec’s Authentication Services, formerly Verisign, has expanded cryptographic options beyond the classic RSA cipher algorithm to also include DSA (Digital Security Algorithm) and, much more significantly, ECC (Elliptic Curve cryptography).
Asymmetric ciphers used with digital certificates and the establishment of SSL/TLS connections base their security on the difficulty of solving certain mathematical problems. RSA relies on the difficulty of discovering the prime factors that must be multiplied together to generate a very large (as in hundreds of digits) number. As a very simple example, it is fairly easy to multiply 23 times 31. But it is much harder to answer the question, “What two integers (other than 713 and 1) must be multiplied to yield a product of 713?” Now imagine if the challenge had 300 digits instead of just 3.
ECC’s security, on the other hand, is based on the relative difficulty of solving certain problems in the algebraic structure of elliptic curves over finite fields. That is nowhere near as easy to illustrate with a simple example, let’s just accept that it’s hard enough given appropriate parameters that we don’t worry about an attacker solving the problem and therefore reading our secrets.
ECC provides an immediate practical advantage, significantly improving performance while maintaining security. NIST says that RSA keys should go from 1024 to 2048 bits in 2014, and this added load on busy web servers could cut the number of simultaneous connections. However, analysis shows that ECC with a 256-bit key is at least 10,000 times as strong as 2048-bit RSA, roughly equivalent to 3072-bit RSA encryption. Smaller keys, less work, more resources to support all those mobile devices accessing cloud data.
Second, and possibly more significantly in the long run, ECC provides strong protection against what could be a catastrophic breakthrough in cryptanalysis.
Prime numbers and the factoring problem have interested mathematicians for millennia. A breakthrough in mathematical analysis is unlikely. But what if computer engineers design a quantum computer that can quickly find the prime factors of very large numbers? RSA security ends that day.
Symantec calls their ECC-based certificate offering “algorithm agility.” They’re the market leader, I hope the other certificate authorities quickly follow suit. Juniper’s SSL/TLS based VPN solution, the world leader, already supports both ECC and DSA. Akamai, F5, Citrix and others have also announced support.
Learning Tree’s Cloud Security Essentials course discusses how digital certificates are at the core of all network security essential when your data is “out in the cloud”.