Blooming Password – A banned password check using a bloom filter
Sorry to say this, but this is actually worse than just truncating the hash.<p>Why? Bloom filters are designed to maintain a reasonable false positive rate while still allowing you to add items extremely quickly (high insertion rate).<p>Since the bad password list is presumably fixed (or almost so) you can do checks faster and with a lower FP rate by just truncating the hashes and prefix sorting the list ahead of time.