Key Space (cryptography)
In cryptography, an algorithm's key space refers to the set of all possible keys that can be used to initialize it. For example, if an algorithm works using a key that is a string of 10 bits, then its key space is the set of all binary strings of length 10. i.e. we have key space of size 210 = 1024.
To avoid adversaries from guessing the key using a brute-force attack, the key space is usually designed to be extremely large. Another desirable attribute is that the key space be flat, having no or very few weak keys. If the key was selected randomly from all possible keys, on average half the key space must be searched to find the solution. However, if an attacker has some knowledge of how the key was likely selected, the search time can be far less.
Read more about Key Space (cryptography): Examples
Famous quotes containing the words key and/or space:
“You have many choices. You can choose forgiveness over revenge, joy over despair. You can choose action over apathy.... You hold the key to how well you make the emotional adjustment to your divorce and consequently how well your children will adapt.”
—Stephanie Marston (20th century)
“What a phenomenon it has been—science fiction, space fiction—exploding out of nowhere, unexpectedly of course, as always happens when the human mind is being forced to expand; this time starwards, galaxy-wise, and who knows where next.”
—Doris Lessing (b. 1919)