All cryptographic algorithms rely on one or more keys. A key is a discrete piece of data, sometimes in the form of a password, that might both "lock" and "unlock" the encryption and decryption process, depending on the type of algorithm. The types and variations of algorithm also determine the sizes of the keys that are used with an algorithm (size specified in bits, for example, 256). Generally, for a given algorithm type, the larger the key, the stronger it makes the algorithm; also for a given algorithm type, the larger the key, the slower it makes the algorithm.