The Wonder of Bloom

A Bloom filter is used to create a probabilistic guess on whether an item is in a data structure, and was created by Burton Howard Bloom (Bloom, 1970). Within the test, the query will define if the value is “possibly in the set” or “definitely not in the set”. Each added element is hashed with two or more hashing methods, and the values generated values are used to set the bits in a bit array. In this example we use a 32-bit bit vector, and use Murmur 2 and FNV for the hashes. Typically we use non-crypto hashes, in order to speed up the process.