ts-crc32

A direct TypeScript port of a tiny CRC-32 (IEEE 802.3) reference implementation.

If you find this project useful, you can support this and further ports at ko-fi.com/scottmoore0.

Upstream provenance

This package is a TypeScript port of aeldidi/crc32 (crc32.c, crc32.h) by Ayman El Didi, released under CC0 1.0 (public domain dedication).

The translated output is validated against canonical CRC-32 reference values, including the well-known check value CRC32("123456789") == 0xCBF43926.

Why this exists

CRC-32 with polynomial 0xEDB88320 is the most-deployed integrity checksum in the world — used inside zlib/gzip, PNG, ZIP archives, Ethernet frames, SCTP, MPEG-2 Transport Stream, JPEG, and the crc32 built-ins of Python (binascii.crc32), Go (hash/crc32 IEEE table), Java (java.util.zip.CRC32), Ruby (Zlib.crc32), Rust (crc32fast), and many others.

ts-crc32 is a direct mechanical translation from a tiny CC0 C reference via the cpp-to-ts translator, so its relationship to the algorithm is inspectable.

Install

npm install ts-crc32

Usage

import { crc32sum, crc32hex } from 'ts-crc32';

// Numeric (uint32)
crc32sum('123456789');             // 3421780262 (= 0xCBF43926)

// Hex string
crc32hex('123456789');             // 'cbf43926'

// Raw bytes
crc32hex(new Uint8Array([0xde, 0xad, 0xbe, 0xef]));

Strings are encoded as UTF-8 before hashing.

API surface

• crc32sum(input: Uint8Array | string): number — returns an unsigned 32-bit integer.
• crc32hex(input: Uint8Array | string): string — returns an 8-character lowercase hex string.

Reference values

The test suite asserts against:

| Input | CRC-32 | |---|---| | "" | 00000000 | | "a" | e8b7be43 | | "abc" | 352441c2 | | "message digest" | 20159d7f | | "abcdefghijklmnopqrstuvwxyz" | 4c2750bd | | "123456789" (canonical check value) | cbf43926 | | "The quick brown fox jumps over the lazy dog" | 414fa339 |

Run:

npm test

Caveats

• Not cryptographic. CRC-32 is a non-cryptographic integrity check, easily forgeable. Use SHA-256 (ts-sha2) when adversaries are in the threat model.
• Algorithm variant. This is the standard "IEEE 802.3" reflected CRC-32 with polynomial 0xEDB88320. If you need CRC-32C (Castagnoli, polynomial 0x82F63B78, used in iSCSI/SCTP/Btrfs/Ceph), this is the wrong package.
• Performance. Direct port of a byte-at-a-time reference. For high-throughput needs prefer Node's built-in crypto.createHash('sha256') for integrity or a slice-by-16 native implementation for raw CRC.

License

CC0 1.0 (public domain). Original C by Ayman El Didi.

See also

• ts-sha2 — SHA-256 for cryptographic integrity
• ts-xxhash — much faster non-cryptographic hash
• ts-fnv-hash — alternative non-cryptographic hash
• cpp-to-ts — the translator that produced this package