Quote:Original post by u235Quote:Original post by Will F
You can decode something encrypted in 128-bit by a brute force attack, but the time required to do so is measured in millions of years.
Just so I am clear, this mean that there are (128!)*2 possible combinations for a 128-bit key? So for a n-bit key, the number of possible keys is (n!)*2?
No, it is 2**n (exponentiation). This is easily seen by treating the key as a binary number and considering it analogously to decimal numbers. 2**128 is still very large, however (about 3.4 * 10**38).
