Black Unicorn writes:
Calling a given cypher "uncrackable" is simple fiction or ignorance.
I will point out for the benefit of all that technically there is one cipher that is unbreakable if it is properly implemented -- the one time pad. However, Black Unicorn's point is generally correct -- information theory dictates that any system other than a one time pad can in theory be broken by brute force once you have ciphertext longer than the unicity distance, which is typically quite short. Unicity distance depends only on the redundancy of the language and the key length in bits (well, technically, the base two log of the number possible keys, but they are usually the same for conventional cryptosystems -- it would make a difference for stuff like RSA but since no one ever really cares about the unicity distance in practice since that sort of brute force search is uninteresting...) Perry