diff --git a/pkinit/asn1.go b/pkinit/asn1.go
index 90d2667..921049c 100644
--- a/pkinit/asn1.go
+++ b/pkinit/asn1.go
@@ -23,7 +23,7 @@ var (
 )
 
 type SignerInfo struct {
-	Version                   uint64 `asn1:"default:1"`
+	Version                   int `asn1:"default:1"`
 	IssuerAndSerialNumber     IssuerAndSerial
 	DigestAlgorithm           pkix.AlgorithmIdentifier
 	AuthenticatedAttributes   []Attribute `asn1:"optional,omitempty,tag:0"`
@@ -48,7 +48,7 @@ type ContentInfo struct {
 }
 
 type SignedData struct {
-	Version                    uint64                     `asn1:"default:1"`
+	Version                    int                        `asn1:"default:1"`
 	DigestAlgorithmIdentifiers []pkix.AlgorithmIdentifier `asn1:"set"`
 	ContentInfo                ContentInfo
 	Certificates               RawCertificates       `asn1:"optional,tag:0"`
@@ -95,9 +95,9 @@ type PKAuthenticator struct {
 	// 	paChecksum              [3] OCTET STRING OPTIONAL,
 	// 	...
 	// asn1
-	CUSec    uint32    `asn1:"tag:0,explicit"`
+	CUSec    int       `asn1:"tag:0,explicit"`
 	CTime    time.Time `asn1:"tag:1,explicit,generalized"`
-	Nonce    uint32    `asn1:"tag:2,explicit"`
+	Nonce    int       `asn1:"tag:2,explicit"`
 	Checksum []byte    `asn1:"tag:3,explicit,optional"`
 }
 
diff --git a/pkinit/asn1_test.go b/pkinit/asn1_test.go
new file mode 100644
index 0000000..404f710
--- /dev/null
+++ b/pkinit/asn1_test.go
@@ -0,0 +1,107 @@
+package pkinit
+
+import (
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"fmt"
+	"math/big"
+	"testing"
+	"time"
+)
+
+func TestASN1Marshal(t *testing.T) {
+	// just a simple asn1.Marshal test that ensures that the asn1 structs do not
+	// contain unexpected types (like uint32 instead of int) that only cause
+	// errors at runtime.
+	tests := []any{
+		SignerInfo{
+			Version: 1,
+			IssuerAndSerialNumber: IssuerAndSerial{
+				IssuerName:   asn1.RawValue{},
+				SerialNumber: big.NewInt(12345),
+			},
+			DigestAlgorithm: pkix.AlgorithmIdentifier{
+				Algorithm:  asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 5},
+				Parameters: asn1.RawValue{Tag: 5},
+			},
+			DigestEncryptionAlgorithm: pkix.AlgorithmIdentifier{
+				Algorithm:  asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1},
+				Parameters: asn1.RawValue{Tag: 5},
+			},
+			EncryptedDigest: []byte("signature"),
+		},
+		Attribute{
+			Type:  asn1.ObjectIdentifier{1, 2, 3},
+			Value: asn1.RawValue{},
+		},
+		IssuerAndSerial{
+			IssuerName:   asn1.RawValue{Tag: 16 /* SEQUENCE */},
+			SerialNumber: big.NewInt(67890),
+		},
+		ContentInfo{
+			ContentType: asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 2},
+		},
+		SignedData{
+			Version: 1,
+			ContentInfo: ContentInfo{
+				ContentType: asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 2},
+			},
+			SignerInfos: []SignerInfo{},
+		},
+		RawCertificates{
+			Raw: []byte{0x30, 0x03, 0x01, 0x00, 0x00},
+		},
+		AuthPack{
+			PKAuthenticator: PKAuthenticator{
+				CUSec:    123,
+				CTime:    time.Date(2024, 1, 1, 12, 0, 0, 0, time.UTC),
+				Nonce:    42,
+				Checksum: []byte("checksum"),
+			},
+		},
+		PKAuthenticator{
+			CUSec:    123,
+			CTime:    time.Date(2024, 1, 1, 12, 0, 0, 0, time.UTC),
+			Nonce:    42,
+			Checksum: []byte("checksum"),
+		},
+		SubjectPublicKeyInfo{
+			Algorithm: AlgorithmIdentifier{
+				Algorithm: asn1.ObjectIdentifier{1, 2, 840, 10046, 2, 1},
+			},
+			PublicKey: asn1.BitString{Bytes: []byte{0x04}, BitLength: 8},
+		},
+		AlgorithmIdentifier{
+			Algorithm: asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1},
+		},
+		DomainParameters{
+			P: big.NewInt(23),
+			G: 5,
+			Q: 11,
+		},
+		PAPKASRep{
+			DHInfo: asn1.RawValue{},
+		},
+		PAPACRequest{
+			IncludePAC: true,
+		},
+		DHRepInfo{
+			DHSignedData:  []byte("data"),
+			ServerDHNonce: []byte("nonce"),
+		},
+		KDCDHKeyInfo{
+			SubjectPublicKey: asn1.BitString{Bytes: []byte{0x04}, BitLength: 8},
+			Nonce:            big.NewInt(999),
+			DHKeyExpication:  time.Date(2024, 1, 1, 12, 0, 0, 0, time.UTC),
+		},
+	}
+
+	for _, val := range tests {
+		t.Run(fmt.Sprintf("%T", val), func(t *testing.T) {
+			_, err := asn1.MarshalWithParams(val, "")
+			if err != nil {
+				t.Errorf("asn1.Marshal() failed for %T: %v", val, err)
+			}
+		})
+	}
+}
diff --git a/pkinit/asreq.go b/pkinit/asreq.go
index 178d54f..e705b78 100644
--- a/pkinit/asreq.go
+++ b/pkinit/asreq.go
@@ -51,9 +51,9 @@ func ConfigureASReq(
 
 	authPack := AuthPack{
 		PKAuthenticator: PKAuthenticator{
-			CUSec:    uint32(now.UnixMicro() - now.Truncate(time.Millisecond).UnixMicro()),
+			CUSec:    int(now.UnixMicro() - now.Truncate(time.Millisecond).UnixMicro()),
 			CTime:    now,
-			Nonce:    mathRand.Uint32(), //nolint:gosec
+			Nonce:    int(mathRand.Uint32()), //nolint:gosec
 			Checksum: pkAuthenticatorChecksum,
 		},
 		ClientPublicValue: SubjectPublicKeyInfo{