Roadmap

go-ruby-securerandom/securerandom is grown test-first, each capability differential-tested against MRI rather than built in isolation. Ruby's SecureRandom formatting layer — the deterministic, interpreter-independent slice over the entropy source — is complete.

Stage	What	Status
Encoders	Hex(n), Base64(n), UrlsafeBase64(n, padding) and RandomBytes(n) with MRI's defaults (n = 16; URL-safe base64 unpadded unless asked). Hex is SIMD-accelerated via go-simd/hex; the base64 family via go-simd/base64.	Done
UUID v4	Uuid() — an RFC 4122 version-4 UUID with the exact xxxxxxxx-xxxx-4xxx-yxxx-… layout (version nibble 4, variant 8/9/a/b).	Done
UUID v7	UuidV7() — MRI 4.0's version-7 UUID: a 48-bit big-endian Unix-milliseconds prefix from an injectable clock plus random bits, version nibble 7.	Done
Alphanumeric & random_number	Alphanumeric(n, chars…) via the Random::Formatter#choose base-size construction; RandomNumber returning a Float in [0,1) for no/non-positive n, an Integer in [0,n) for a positive integer, a Float in [0,n) for a positive float (RandomInt / RandomFloat typed conveniences).	Done
SIMD acceleration	The hex path on go-simd/hex and the base64 paths on go-simd/base64 — go-asmgen kernels, byte-identical drop-ins for the standard library, CGO=0 SIMD across all six 64-bit arches.	Done
Differential oracle & coverage	Each method run under the system ruby and checked for the same format, length, charset and UUID bit-layout (never exact bytes, since both sides draw independent CSPRNGs); 100% coverage, gofmt + go vet clean, green across all six 64-bit Go arches and three OSes.	Done

Documented out-of-scope boundaries

These are deliberate, recorded so the module's surface is unambiguous:

• No interpreter. The library implements the deterministic formatting over an injectable entropy source; it never runs arbitrary Ruby. That is why rbgo binds this module rather than the reverse.
• Format, not exact bytes. Because the default source is a CSPRNG, conformance is asserted on format, length, charset and UUID bit-layout — exact bytes are only reproducible when a fixed RandSource is injected.
• Edge cases match MRI by behaviour. Non-positive random_number returns a float in [0,1); a single-element/empty Alphanumeric set returns the only reachable string rather than looping forever as MRI's #choose would.
• Reference is reference Ruby (MRI 4.0.5). Conformance targets MRI's behaviour, pinned by the differential oracle.

See Usage & API for the surface and Why pure Go for the randomness/formatting split.