In []:
 
 
FNV (or Fowler-Noll-Vo is a non-cryptographic hash function.
 
Aside from code simplicity, this hash function is not particularly good at anything.
 
Python implementation
 
Below are self-contained implementations of the FNV hash function in Python. Feel free to grab one and copy-paste it into your projects.
 
FNV-1
 
This function reads a byte array and produces a U64 hash value.
 
 In [2]:
def fnv1(buf: bytes) -> int:
    h = 14695981039346656037

    for b in buf:
        h *= 1099511628211
        h &= 0xFFFFFFFFFFFFFFFF  # 64-bit mask
        h ^= b

    return h
 
 
 In [3]:
fnv1(b"Hello world")
fnv1(b"Hello wordl")
 
 
 Out [3]:
13583674344491166159
 
 
 Out [3]:
13583665548398140543
 
 
FNV-1a
 
This is the same as FNV-1, but the multiplication and XOR operations are swapped. This is done to improve avalanche effect.
 
 In [4]:
def fnv1a(buf: bytes) -> int:
    h = 14695981039346656037

    for b in buf:
        h ^= b
        h *= 1099511628211
        h &= 0xFFFFFFFFFFFFFFFF  # 64-bit mask

    return h
 
 
 In [5]:
fnv1a(b"Hello world")
fnv1a(b"Hello wordl")
 
 
 Out [5]:
2815866345377719495
 
 
 Out [5]:
2823738848634196455
 
 
References and useful links