Brute Force Attack Time Calculator

Key space size doubles with every additional bit, since each new bit doubles the number of possible key values. Since brute-force attack time is directly proportional to the size of the key space being searched, doubling the key space roughly doubles the average number of attempts needed and therefore roughly doubles attack time, assuming the attacker's computing power stays the same.

An attacker doesn't need to check every possible key to succeed -- since the correct key is equally likely to be anywhere in the space, on average it will be found after about half the space has been checked. Using the full key space as "worst case" would overstate typical attack time; averaging over many attack attempts, half the key space is the statistically expected number of tries.

Combined computing power in this calculator is operations per second multiplied by the number of parallel processors working simultaneously, so doubling the processor count roughly halves attack time for the same key space and per-processor speed -- provided the attack genuinely parallelizes cleanly across processors, which is generally true for brute force since each processor can independently test a different subset of keys.

No -- exhaustive search has a well-defined mathematical basis (half of a known key space), but a real dictionary attack's actual search space depends entirely on the specific word list, common-password list, or rule set the attacker uses, which varies enormously in practice. This calculator models dictionary attacks as a smaller illustrative fraction of the key-space figure rather than a precisely modeled real-world word list, so treat that result as a rough comparison, not a precise prediction.