go-gostcrypto-compat

GPL-3.0 companion to go-gostcrypto. It holds everything that touches the GPL-licensed go.stargrave.org/gogost/v7 reference implementation, kept in a separate module so go-gostcrypto itself stays pure-Go BSD-2-Clause with zero GPL in its dependency graph.

Two things live here:

1. Compatibility mode — package gostcryptocompat (module root): a gogost-backed implementation of the go-gostcrypto facade API. Import this if you want the reference backend rather than the clean-room one. Same []byte-in/[]byte-out surface as go-gostcrypto.
2. Parity tests — parity/<primitive>/: the clean-room ↔ gogost differential tests. Each imports the BSD clean-room primitive from go-gostcrypto and compares it against gogost byte-for-byte. This is the gate that proves go-gostcrypto's BSD code matches the reference.

go-gostcrypto-compat/
  <facade>.go            package gostcryptocompat — gogost-backed facade + KAT/vector tests
  parity/<prim>/         clean-room (go-gostcrypto) ↔ gogost differential tests
  third_party/gogost/    vendored gogost (GPL-3.0)

Requirements

• Go 1.24 or later.
• A checkout of go-gostcrypto as a sibling directory (../go-gostcrypto) — see below.
• Linux, macOS, or any other platform the Go toolchain supports; pure-Go, builds with CGO_ENABLED=0.

Quick start

go-gostcrypto is co-developed and not yet published, and gogost is not resolvable through the stock Go proxy, so both are wired in by replace directives in go.mod:

replace github.com/tarantool/go-gostcrypto => ../go-gostcrypto
replace go.stargrave.org/gogost/v7        => ./third_party/gogost

Check go-gostcrypto out as a sibling directory (../go-gostcrypto), then:

go build ./...
go test  ./...      # facade KAT/vector tests + all parity tests
make test           # same, via the Makefile (see `make help`)

Documentation

API documentation is published on pkg.go.dev. Locally, browse it with go doc -http=:6060.

Contributing

See CONTRIBUTING.md for the development workflow, commit message conventions, and the pre-push gate.

Licensing

GPL-3.0. This module is a combined work: it links and vendors go.stargrave.org/gogost/v7, which is GPL-3.0, so the whole module — the gostcryptocompat facade and the parity tests alike — is GPL-3.0. It is kept as a deliberately separate module from go-gostcrypto so this GPL surface never enters go-gostcrypto's dependency graph; go-gostcrypto itself stays BSD-2-Clause and links none of this. See LICENSE for the full license text.

gogost is Sergey Matveev's reference implementation, distributed only through his own infrastructure (a GOPROXY behind a custom CA, and a SHA-256 git repository) — neither resolves through the stock Go toolchain, so the v7.0.0 source is vendored under third_party/gogost and wired in by the replace above. See third_party/gogost/UPSTREAM.md for the exact tag/commit and the update procedure.