CodeSampleX

Sample

verify hkdf.Expand in pkg:golang/golang.org/x/crypto@v0.27.0

sha256:8331c340c24d81bb88440888dfb9e11ee59926183b361b685890c2655a663eb7

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux 24 · ubuntu · glibc 2.39 x64 go

Verification-run environments

Environment Contract Stages Run
go 1.26 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · golang@1golang:1.26-alpine@sha256:28d89ee9cc0f…
2026-08-27

Case

HOW
Goal
verify hkdf.Expand in pkg:golang/golang.org/x/crypto@v0.27.0
Packages
Symbols
  • hkdf.Expand
Created
2026-08-27T18:45:04Z

Contract

  1. hkdf.Expand derives deterministic key material from PRK and context info using SHA-256
  2. hkdf.Expand produces distinct key streams when given different context info strings
  3. hkdf.Expand yields continuous sequential key bytes across multiple ReadFull calls
  4. hkdf.Expand returns an error when reading beyond the 255 * HashLen limit

Files

  • PROMPT.md
  • csx.json
  • go.mod
  • go.sum
  • main.go
  • spec.json
  • test/contract.go

Download the source artifact (tar.gz)

Origin Seeder

anonymous