demo: Update to Go 1.27, switch to standard library ML-DSA

Author: davidben

demo/cosign.go

@@ -1,20 +1,18 @@
 package main
 
 import (
-	"bytes"
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/ed25519"
 	"crypto/elliptic"
+	"crypto/mldsa"
 	"crypto/rand"
 	"crypto/sha256"
 	_ "crypto/sha512"
 	"crypto/x509"
 	"fmt"
 	"io"
-	"slices"
 
-	"filippo.io/mldsa"
 	"golang.org/x/crypto/cryptobyte"
 )
 
@@ -28,47 +26,6 @@ func tlogOrigin(id TrustAnchorID) string {
 	return fmt.Sprintf("oid/1.3.6.1.4.1.%s", id)
 }
 
-// When ML-DSA is added to the Go standard library, these wrappers can be
-// removed.
-
-var (
-	mldsa44PKCS8Prefix = []byte{0x30, 0x34, 0x02, 0x01, 0x00, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x11, 0x04, 0x22, 0x80, 0x20}
-	mldsa65PKCS8Prefix = []byte{0x30, 0x34, 0x02, 0x01, 0x00, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x12, 0x04, 0x22, 0x80, 0x20}
-	mldsa87PKCS8Prefix = []byte{0x30, 0x34, 0x02, 0x01, 0x00, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x13, 0x04, 0x22, 0x80, 0x20}
-
-	mldsa44SPKIPrefix = []byte{0x30, 0x82, 0x05, 0x32, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x11, 0x03, 0x82, 0x05, 0x21, 0x00}
-	mldsa65SPKIPrefix = []byte{0x30, 0x82, 0x07, 0xb2, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x12, 0x03, 0x82, 0x07, 0xa1, 0x00}
-	mldsa87SPKIPrefix = []byte{0x30, 0x82, 0x0a, 0x32, 0x30, 0x0b, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x03, 0x13, 0x03, 0x82, 0x0a, 0x21, 0x00}
-)
-
-func parsePKCS8PrivateKey(der []byte) (key any, err error) {
-	if seed, ok := bytes.CutPrefix(der, mldsa44PKCS8Prefix); ok && len(seed) == mldsa.PrivateKeySize {
-		return mldsa.NewPrivateKey(mldsa.MLDSA44(), seed)
-	}
-	if seed, ok := bytes.CutPrefix(der, mldsa65PKCS8Prefix); ok && len(seed) == mldsa.PrivateKeySize {
-		return mldsa.NewPrivateKey(mldsa.MLDSA65(), seed)
-	}
-	if seed, ok := bytes.CutPrefix(der, mldsa87PKCS8Prefix); ok && len(seed) == mldsa.PrivateKeySize {
-		return mldsa.NewPrivateKey(mldsa.MLDSA87(), seed)
-	}
-	return x509.ParsePKCS8PrivateKey(der)
-}
-
-func marshalPKIXPublicKey(pub any) ([]byte, error) {
-	if ml, ok := pub.(*mldsa.PublicKey); ok {
-		switch ml.Parameters() {
-		case mldsa.MLDSA44():
-			return append(slices.Clip(mldsa44SPKIPrefix), ml.Bytes()...), nil
-		case mldsa.MLDSA65():
-			return append(slices.Clip(mldsa65SPKIPrefix), ml.Bytes()...), nil
-		case mldsa.MLDSA87():
-			return append(slices.Clip(mldsa87SPKIPrefix), ml.Bytes()...), nil
-		}
-		panic("unknown ML-DSA parameters")
-	}
-	return x509.MarshalPKIXPublicKey(pub)
-}
-
 type Cosigner struct {
 	Version            DraftVersion
 	ID                 TrustAnchorID
@@ -79,7 +36,7 @@ type Cosigner struct {
 }
 
 func NewCosignerFromConfig(version DraftVersion, config *CosignerConfig) (*Cosigner, error) {
-	priv, err := parsePKCS8PrivateKey(config.PrivateKey)
+	priv, err := x509.ParsePKCS8PrivateKey(config.PrivateKey)
 	if err != nil {
 		return nil, err
 	}
@@ -116,7 +73,7 @@ func NewCosignerFromConfig(version DraftVersion, config *CosignerConfig) (*Cosig
 		signer = ed
 		opts = crypto.Hash(0)
 	case SignatureAlgorithmMLDSA44, SignatureAlgorithmMLDSA65, SignatureAlgorithmMLDSA87:
-		var params *mldsa.Parameters
+		var params mldsa.Parameters
 		switch config.SignatureAlgorithm {
 		case SignatureAlgorithmMLDSA44:
 			params = mldsa.MLDSA44()

demo/encode.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"cmp"
 	"crypto/sha256"
+	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/asn1"
 	"errors"
@@ -431,7 +432,7 @@ func CreateCertificate(config *CAConfig, issuanceLog *MerkleTree, cosigners []*C
 
 func CreateCACertificate(config *CAConfig, cosigner *Cosigner) ([]byte, error) {
 	pub := cosigner.Signer.Public()
-	spki, err := marshalPKIXPublicKey(pub)
+	spki, err := x509.MarshalPKIXPublicKey(pub)
 	if err != nil {
 		return nil, err
 	}

go.mod

@@ -1,7 +1,5 @@
 module github.com/ietf-plants-wg/merkle-tree-certs
 
-go 1.25.5
+go 1.27
 
 require golang.org/x/crypto v0.54.0
-
-require filippo.io/mldsa v0.0.0-20260215214346-43d0283efc3e

go.sum

@@ -1,4 +1,2 @@
-filippo.io/mldsa v0.0.0-20260215214346-43d0283efc3e h1:VsUbObBMxXlc23Eb9VeeJYE4jvTs87qa5RqSN2U5FJU=
-filippo.io/mldsa v0.0.0-20260215214346-43d0283efc3e/go.mod h1:32qQ5yj3R24Eu03iWFWchdC3OB653wPvoepWejkefbY=
 golang.org/x/crypto v0.54.0 h1:YLIA59K4fiNzHzjnZt2tUJQjQtUWfWbeHBqKtk3eScw=
 golang.org/x/crypto v0.54.0/go.mod h1:KWL8ny2AZdGR2cWmzeHrp2azQPGogOv+HeQaVEXC2dk=