On 6/10/07, Dinesh Joshi dinesh.a.joshi@gmail.com wrote:
Not forever. At a time DES was considered to be unbreakable. But now it is very much breakable and that too in a practical amount of time. Similarly, RSA will become breakable as the technology advances.
Not sure I agree with the flat analogy. The weakness of DES was its key length -- 56 bits was just right for NSA's supercomputers to crack the code in a reasonable amount of time back then. 64 bits would have made it much stronger.
Unbreakable is actually the wrong word to use for encryption schemes. RSA is breakable even today but it'll take an exponentially large ( read: practically not viable ) amount of time to break. So it is as good as "unbreakable" - at the moment.
One route to breaking a crypt is through algorithm flaws. An open algorithm will get fixed faster in such a case.
In normal cases, even if computing speed increases by 2 times every year, all I need to do is increase my key length by a bit to make my crypt much stronger than required to offset the increase in computing speed..
The most feasible way to break a crypt is to attack the weakest link -- users.