crypto/ed25519: unable to run the PCT - "Ed25519 sign and verify PCT" while calling ed25519.GenerateKey()

[meetwithabhishek]

Go version

go version go1.25.7 linux/amd64

Output of go env in your module/workspace:

AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='on'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/abhishek/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/abhishek/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build4060677167=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/home/abhishek/go/src/tmp-projects/go.mod'
GOMODCACHE='/home/abhishek/go/pkg/mod'
GONOPROXY='gitlab.protectv.local'
GONOSUMDB='gitlab.protectv.local'
GOOS='linux'
GOPATH='/home/abhishek/go'
GOPRIVATE='gitlab.protectv.local'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/abhishek/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.25.7'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

I am generating an Ed25519 key and expecting that the underlying PCT: Ed25519 sign and verify PCT should run as part of it, but it is not running.
I am, of course, running the program in fips mode.

It seems like GenerateKey function of crypto/ed25519 doesn't call the GenerateKey() function of crypto/internal/fips140/ed25519 package, which triggers the PCT.

How should I trigger the PCT?

Following is the program I am using to generate Ed25519 key:

package main

import (
	"crypto/ed25519"
	"crypto/rand"
	"crypto/x509"
	"encoding/pem"
	"io/ioutil"

	"fmt"
	"os"
)

// GenerateSaveEd25519 generates and saves ed25519 keys to disk after
// encoding into PEM format
func GenerateSaveEd25519(fb string) error {

	var (
		err   error
		b     []byte
		block *pem.Block
		pub   ed25519.PublicKey
		priv  ed25519.PrivateKey
	)

	pub, priv, err = ed25519.GenerateKey(rand.Reader)
	if err != nil {
		fmt.Printf("Generation error : %s", err)
		os.Exit(1)
	}

	b, err = x509.MarshalPKCS8PrivateKey(priv)
	if err != nil {
		return err
	}

	block = &pem.Block{
		Type:  "PRIVATE KEY",
		Bytes: b,
	}

	err = ioutil.WriteFile(fb, pem.EncodeToMemory(block), 0600)
	if err != nil {
		return err
	}

	// public key
	b, err = x509.MarshalPKIXPublicKey(pub)
	if err != nil {
		return err
	}

	block = &pem.Block{
		Type:  "PUBLIC KEY",
		Bytes: b,
	}

	fileName := fb + ".pub"
	err = ioutil.WriteFile(fileName, pem.EncodeToMemory(block), 0644)
	return err

}

func main() {

	if len(os.Args) != 2 || os.Args[1] == "-h" || os.Args[1] == "--help" {
		fmt.Printf("%s : generate pem formatted ed25519 keys\n", os.Args[0])
		fmt.Println("    provide a single argument for the private key name")
		fmt.Println("    the public key name will have '.pub' appended")
		os.Exit(1)
	}

	FileBaseName := os.Args[1]

	if err := GenerateSaveEd25519(FileBaseName); err != nil {
		fmt.Printf("Error : %s\n", err)
		os.Exit(1)
	}
}

What did you see happen?

Program Output:

GODEBUG=fips140=debug go run pct.go /tmp/key
FIPS 140-3 self-test passed: cSHAKE128
FIPS 140-3 self-test passed: SHA2-256
FIPS 140-3 self-test passed: SHA2-512
FIPS 140-3 self-test passed: HMAC-SHA2-256
fips140: verified code+data
FIPS 140-3 self-test passed: AES-CBC
FIPS 140-3 self-test passed: CTR_DRBG
FIPS 140-3 self-test passed: CounterKDF
FIPS 140-3 self-test passed: HKDF-SHA2-256
FIPS 140-3 self-test passed: ML-KEM-768
FIPS 140-3 self-test passed: TLSv1.2-SHA2-256
FIPS 140-3 self-test passed: TLSv1.3-SHA2-256
FIPS 140-3 self-test passed: cSHAKE128
FIPS 140-3 self-test passed: SHA2-256
FIPS 140-3 self-test passed: SHA2-512
FIPS 140-3 self-test passed: HMAC-SHA2-256
fips140: verified code+data
FIPS 140-3 self-test passed: AES-CBC
FIPS 140-3 self-test passed: CTR_DRBG
FIPS 140-3 self-test passed: CounterKDF

What did you expect to see?

FIPS 140-3 self-test passed: Ed25519 sign and verify PCT

[gopherbot]

Change https://go.dev/cl/745800 mentions this issue: crypto/ed25519: use FIPS 140-3 GenerateKey and enforce fips140=only

[gopherbot]

Change https://go.dev/cl/746561 mentions this issue: builtin: update new function comment