HashCheck

Calculate and verify SHA-256/SHA-512 checksums, plus deterministic SHA-256 release manifests.

HashCheck is a small, security-focused command-line tool for calculating and verifying checksums. The current development line also integrates deterministic multi-file release-manifest creation and verification, consolidating the useful core direction previously explored by ReleaseSeal.

It is Linux-first, uses streaming file I/O, and has no telemetry, backend, account system, or network functionality.

Status

HashCheck v0.1.0 is the current public release.

A prebuilt Linux x86_64 archive and SHA-256 checksum are available on the GitHub Releases page.

Release-manifest commands described below are part of the current development line and should not be treated as included in the existing v0.1.0 binary until a later release is published.

Features

Released in v0.1.0:

• SHA-256 by default
• SHA-512 with --sha512
• verify a file with --expect <HASH>
• case-insensitive expected hexadecimal checksums
• streaming hashing: files are processed in fixed-size chunks instead of being loaded fully into RAM
• clear exit codes for scripts and automation
• no file contents are printed

Current development line additionally includes:

• deterministic SHA-256 manifests for multiple release artifacts
• stable path ordering in generated manifests
• relative manifest entries constrained to the manifest directory
• traversal/absolute-path rejection during manifest verification
• atomic manifest replacement through a temporary file and rename

Single-file usage

Calculate SHA-256:

hashcheck file.iso

Calculate SHA-512:

hashcheck --sha512 file.iso

Verify SHA-256:

hashcheck file.iso --expect <HASH>

Verify SHA-512:

hashcheck --sha512 file.iso --expect <HASH>

Expected hashes may use uppercase or lowercase hexadecimal characters.

Release manifests — development line

Create a deterministic SHA-256 manifest:

hashcheck manifest create dist/SHA256SUMS \
  dist/app-linux.tar.gz \
  dist/app-linux.tar.gz.asc

Verify it later:

hashcheck manifest verify dist/SHA256SUMS

Manifest entries must remain inside the manifest directory. Absolute paths and parent-directory traversal are rejected during parsing/verification.

This is checksum integrity, not artifact authenticity: a manifest is only as trustworthy as the channel from which you obtained it.

Relationship to ReleaseSeal

ReleaseSeal began as a focused experiment for deterministic SHA-256 release manifests. That useful core behavior is now being integrated into HashCheck so checksum and checksum-manifest workflows do not need to remain separate products.

The ReleaseSeal repository remains public as a focused development history/reference rather than being deleted or republished. Broader signing, provenance, or SBOM work is not claimed by HashCheck unless it is separately implemented and tested.

Install on Linux x86_64

Download these files from the current v0.1.0 release:

• hashcheck-v0.1.0-x86_64-unknown-linux-gnu.tar.gz
• hashcheck-v0.1.0-x86_64-unknown-linux-gnu.tar.gz.sha256

Verify and extract:

sha256sum -c hashcheck-v0.1.0-x86_64-unknown-linux-gnu.tar.gz.sha256
tar -xzf hashcheck-v0.1.0-x86_64-unknown-linux-gnu.tar.gz
./hashcheck --version

You can optionally place hashcheck somewhere on your PATH, such as ~/.local/bin.

Exit codes

Code	Meaning
0	Hash calculated successfully, expected hash matched, or manifest verified
1	Expected hash mismatched, or at least one manifest entry mismatched/failed
2	Usage, manifest-format, or I/O error

Build from source

Requires Rust 1.74 or newer.

git clone https://github.com/BLCCoreStudio/HashCheck.git
cd HashCheck
cargo build --release --locked
./target/release/hashcheck --version

The binary will be at target/release/hashcheck on Linux/macOS and target\release\hashcheck.exe on Windows.

Development checks

cargo fmt --all -- --check
cargo clippy --locked --all-targets --all-features -- -D warnings
cargo test --locked --all-features

GitHub Actions runs formatting, Clippy with warnings denied, tests on Linux, and tests on Windows/macOS.

Security note

A checksum only proves that the bytes you hashed match the expected checksum. It does not prove that the expected checksum or manifest itself is trustworthy. Obtain expected hashes/manifests from a trusted source or channel when authenticity matters.

See SECURITY.md for vulnerability reporting.

Contributing

Contributions are welcome. See CONTRIBUTING.md.

License

MIT. See LICENSE.

Built by BLC Core Studio.