Hashing and Checksums

Simple Checksum

def checksum(data: bytes) -> int:
    total = 0
    for b in data:
        total = (total + b) & 0xff
    return total

FNV-1a Hash

def fnv1a(data: bytes) -> int:
    hash_val = 0x811c9dc5
    for b in data:
        hash_val ^= b
        hash_val *= 0x01000193
        hash_val &= 0xffffffff
    return hash_val

When to Use hashlib

For SHA-256, MD5, and BLAKE3, use hashlib — these are C-accelerated. Use Pyvorin for custom or non-cryptographic hashes.