golang.org/x/crypto v0.55.0: argon2.Key

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify golang.org/x/crypto/argon2.Key in pkg:golang/golang.org/x/crypto@v0.55.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/crypto@v0.55.0
Demonstrate these symbols/APIs:
  - golang.org/x/crypto/argon2.Key

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:5b5e84ed2bd28c05f91c709a747d2b01c53f78981a3d9d2a648ec8a807dfb42a","contract":["argon2.Key returns derived key with exact requested keyLen","argon2.Key is deterministic for identical password, salt, and parameters","argon2.Key produces distinct output when password or salt differs","argon2.Key produces distinct output when iteration time or memory parameter differs"],"goal":"verify golang.org/x/crypto/argon2.Key in pkg:golang/golang.org/x/crypto@v0.55.0","kind":"HOW","packages":["pkg:golang/golang.org/x/crypto@v0.55.0"],"schemaVersion":1,"symbols":["golang.org/x/crypto/argon2.Key"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/crypto@v0.55.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/crypto@v0.55.0","symbols":["golang.org/x/crypto/argon2.Key"],"verifierAdapter":"golang@1"}

module sample

go 1.25.0

require golang.org/x/crypto v0.55.0

require golang.org/x/sys v0.47.0 // indirect

golang.org/x/crypto v0.55.0 h1:+KWHjbgOaAQ66dh/YlkZKHlz9ZUlq61AFirAR9ntP8M=
golang.org/x/crypto v0.55.0/go.mod h1:uq0V9dE/fzQuJtbnL+2EhWOE63vo164FY8xqEnV9xis=
golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=

package main

import (
	"encoding/hex"
	"fmt"

	"golang.org/x/crypto/argon2"
)

// DeriveKey derives a cryptographic key from a password and salt using Argon2i.
func DeriveKey(password, salt []byte, time, memory uint32, threads uint8, keyLen uint32) []byte {
	return argon2.Key(password, salt, time, memory, threads, keyLen)
}

func main() {
	password := []byte("sample-password")
	salt := []byte("sample-salt-1234")
	time := uint32(1)
	memory := uint32(64 * 1024)
	threads := uint8(4)
	keyLen := uint32(32)

	key := DeriveKey(password, salt, time, memory, threads, keyLen)
	fmt.Printf("Derived Key (%d bytes): %s\n", len(key), hex.EncodeToString(key))
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/crypto/argon2.Key in pkg:golang/golang.org/x/crypto@v0.55.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/crypto@v0.55.0"
  ],
  "symbols": [
    "golang.org/x/crypto/argon2.Key"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

	"golang.org/x/crypto/argon2"
)

func main() {
	// 1. argon2.Key returns key with exact requested keyLen
	{
		password := []byte("secret-password")
		salt := []byte("random-salt-1234")
		time := uint32(1)
		memory := uint32(32 * 1024)
		threads := uint8(2)

		key32 := argon2.Key(password, salt, time, memory, threads, 32)
		if len(key32) != 32 {
			fmt.Fprintf(os.Stderr, "FAIL: expected keyLen 32, got %d\n", len(key32))
			os.Exit(1)
		}

		key16 := argon2.Key(password, salt, time, memory, threads, 16)
		if len(key16) != 16 {
			fmt.Fprintf(os.Stderr, "FAIL: expected keyLen 16, got %d\n", len(key16))
			os.Exit(1)
		}
	}

	// 2. argon2.Key is deterministic for identical password, salt, and parameters
	{
		password := []byte("fixed-password")
		salt := []byte("fixed-salt-value")
		time := uint32(1)
		memory := uint32(32 * 1024)
		threads := uint8(2)
		keyLen := uint32(32)

		key1 := argon2.Key(password, salt, time, memory, threads, keyLen)
		key2 := argon2.Key(password, salt, time, memory, threads, keyLen)

		if !bytes.Equal(key1, key2) {
			fmt.Fprintf(os.Stderr, "FAIL: expected deterministic output for identical inputs\n")
			os.Exit(1)
		}
	}

	// 3. argon2.Key produces distinct output when password or salt differs
	{
		salt := []byte("fixed-salt-value")
		time := uint32(1)
		memory := uint32(32 * 1024)
		threads := uint8(2)
		keyLen := uint32(32)

		keyPassA := argon2.Key([]byte("password-alpha"), salt, time, memory, threads, keyLen)
		keyPassB := argon2.Key([]byte("password-bravo"), salt, time, memory, threads, keyLen)
		if bytes.Equal(keyPassA, keyPassB) {
			fmt.Fprintf(os.Stderr, "FAIL: expected different keys for different passwords\n")
			os.Exit(1)
		}

		password := []byte("fixed-password")
		keySaltA := argon2.Key(password, []byte("salt-alpha-12345"), time, memory, threads, keyLen)
		keySaltB := argon2.Key(password, []byte("salt-bravo-12345"), time, memory, threads, keyLen)
		if bytes.Equal(keySaltA, keySaltB) {
			fmt.Fprintf(os.Stderr, "FAIL: expected different keys for different salts\n")
			os.Exit(1)
		}
	}

	// 4. argon2.Key produces distinct output when iteration time or memory parameter differs
	{
		password := []byte("fixed-password")
		salt := []byte("fixed-salt-value")
		threads := uint8(2)
		keyLen := uint32(32)

		keyTime1 := argon2.Key(password, salt, 1, 32*1024, threads, keyLen)
		keyTime2 := argon2.Key(password, salt, 2, 32*1024, threads, keyLen)
		if bytes.Equal(keyTime1, keyTime2) {
			fmt.Fprintf(os.Stderr, "FAIL: expected different keys for different time iterations\n")
			os.Exit(1)
		}

		keyMem1 := argon2.Key(password, salt, 1, 32*1024, threads, keyLen)
		keyMem2 := argon2.Key(password, salt, 1, 64*1024, threads, keyLen)
		if bytes.Equal(keyMem1, keyMem2) {
			fmt.Fprintf(os.Stderr, "FAIL: expected different keys for different memory settings\n")
			os.Exit(1)
		}
	}

	fmt.Println("PASS: all contract assertions passed")
}