Secure ICA Technical Overview Back to Secure ICA Section

The only way to break a secure algorithm is to try every possible key on a sequence of encrypted data. As the size of the key increases the time and effort required to guess the correct key increases. Trying every possible key is known as a brute force attack.

A key 8 bits long contains 256 possible keys. A brute force attack on this key would be simple. However, the number of possible keys increases exponentially with key size. A 56-bit key contains 256 possible keys. If an attacker tried one million keys a second, it would take 2285 years to try each one. A 64-bit key would take the same attacker 585,000 years.

It is estimated that a million dollar parallel processing computer can crack a 128-bit key in 10¹⁸ years. For comparison, the age of the Universe is estimated at 10¹⁰ years.

It is important to evaluate the requirements for encryption. If the data being encrypted is time sensitive, shorter keys can be used. For example, if you are encrypting details of a planned merger, the data must be kept secret for a few months. If an attacker manages to decrypt the data twenty years after the merger is complete, whatever information is gained will be useless