Bodu.IO.Hashing 1.0.0

Bodu.IO.Hashing

API stability — Stable. The public API surface is committed; breaking changes are reserved for a major-version bump per SemVer.

Non-cryptographic hashing, checksums, and check-digit algorithms for .NET 8. Hash algorithms derive from System.IO.Hashing.NonCryptographicHashAlgorithm, so they expose the standard Append / GetCurrentHash / GetHashAndReset streaming surface and slot into existing pipelines. This package covers data-integrity and identifier-validation use cases — not security. For keyed/cryptographic hashing use the sibling Bodu.Security.Cryptography package or the platform System.Security.Cryptography types.

Installation

dotnet add package Bodu.IO.Hashing

Targets net8.0.

Quick start

using Bodu.IO.Hashing.Checksums;
using Bodu.IO.Hashing.CheckDigits;

// CRC: one parametric engine, 112 catalogued standards.
var crc = new Crc(CrcStandard.CRC32_ISOHDLC);           // the ubiquitous zip/png CRC-32
byte[] digest = crc.ComputeHash("123456789"u8);          // one-shot over bytes

// Or stream it: the standard NonCryptographicHashAlgorithm surface.
crc.Append("1234"u8);
crc.Append("56789"u8);
byte[] same = crc.GetHashAndReset();                     // equals the one-shot digest

// Check digits: static Compute / IsValid per identifier scheme.
bool ok = Iban.IsValid("GB82WEST12345698765432");        // true (electronic format, no spaces)
char check = Luhn.Compute("7992739871");                 // '3' -> card number 79927398713
bool valid = Isbn13.IsValid("9780306406157");            // true

Crc implements IResumableHashAlgorithm, so a stored digest can be extended with more data without replaying the original input. See the guides for the full catalogue, streaming, and verification surfaces.

Checksums and non-cryptographic hashes

CRC

A single parametric Crc engine drives the full RevEng catalogue — 112 standards spanning widths from CRC-3 to CRC-64 (CRC-3, -4, -5, -6, -7, -8, -10…-17, -21, -24, -30, -31, -32, -40, -64). CrcStandard is the immutable parameter bundle (polynomial, init, reflect-in/out, final XOR); the catalogue is exposed through the CrcStandards enum, and CrcLookupTableCache shares lookup tables across instances with matching (width, polynomial, reflectIn). Crc implements IResumableHashAlgorithm, so a digest can be extended from a prior hash without replaying the original input.

Check digits

Streaming check-digit algorithms (Append(ReadOnlySpan<char>) → GetCurrentCheckDigit()) for identifier validation and generation:

Decimal algorithms derive from CheckDigitAlgorithm; alphanumeric and multi-character schemes derive from AlphanumericCheckDigitAlgorithm / MultiCharCheckDigitAlgorithm, with CheckDigitInputAlphabet / CheckDigitOutputAlphabet selecting the permitted character sets.

Streaming and one-shot APIs

The extension surface on NonCryptographicHashAlgorithm adds AppendData(Stream), one-shot ComputeHash(...) / ComputeHashAsync(Stream), and constant-time VerifyHash / TryVerifyHash (sync and async) over the standard incremental Append / GetCurrentHash / Reset methods.

Runnable samples

The repository ships offline, dotnet run-able sample projects for this package — the CRC catalogue and checksum families, streaming and resumable digests, identifier check digits across domains, and a custom check-digit scheme proven by the shared contract-test base — under samples/IO.Hashing/.

Testing

Tests live in test/ as MSTest partial classes mirroring src/. Run tiers via the runsettings files at the solution root:

dotnet test Bodu.IO.Hashing/test/Bodu.IO.Hashing.Test.csproj --settings smoke.runsettings
dotnet test Bodu.IO.Hashing/test/Bodu.IO.Hashing.Test.csproj --settings bvt.runsettings
dotnet test Bodu.IO.Hashing/test/Bodu.IO.Hashing.Test.csproj --settings regression.runsettings

Algorithms are validated against published known-answer vectors through the shared NonCryptographicHashAlgorithmContractTests<TAlgorithm>, CheckDigitContractTests<TAlgorithm>, and MultiCharCheckDigitContractTests<TAlgorithm> bases, with the full CRC catalogue exercised in the Regression tier.

License

MIT. © Bodu Pty. Ltd.