What does "keyspace" refer to in a cryptosystem?

In a cryptosystem, "keyspace" refers specifically to the range of all possible values for a key. This concept is crucial in understanding the strength and security of a cryptographic system. The larger the keyspace, the more potential keys exist, making it significantly more challenging for an attacker to successfully guess or brute-force the key used in a cryptographic operation.

For instance, if a cryptographic algorithm uses a key size of n bits, then the keyspace includes all possible combinations of those bits, which amounts to 2^n different possible keys. This exponential growth in keyspace emphasizes the importance of using sufficiently large key sizes to enhance security. Therefore, the integrity and confidentiality provided by a cryptosystem heavily depend on its keyspace characteristics.