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// Copyright 2022 The Sigstore Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package signer
import (
"context"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rand"
"crypto/sha256"
"crypto/sha512"
"hash"
"os"
"path/filepath"
"strings"
"testing"
"github.com/google/tink/go/aead"
"github.com/sigstore/sigstore/pkg/cryptoutils"
"github.com/google/tink/go/keyset"
"github.com/google/tink/go/proto/tink_go_proto"
"github.com/google/tink/go/signature"
)
type TestStruct struct {
keyTemplate *tink_go_proto.KeyTemplate
h hash.Hash
}
func TestNewTinkSigner(t *testing.T) {
aeskh, err := keyset.NewHandle(aead.AES256GCMKeyTemplate())
if err != nil {
t.Fatalf("error creating AEAD key handle: %v", err)
}
a, err := aead.New(aeskh)
if err != nil {
t.Fatalf("error creating AEAD key: %v", err)
}
kh, err := keyset.NewHandle(signature.ECDSAP256KeyTemplate())
if err != nil {
t.Fatalf("error creating ECDSA key handle: %v", err)
}
khsigner, err := KeyHandleToSigner(kh)
if err != nil {
t.Fatalf("error converting ECDSA key handle to signer: %v", err)
}
dir := t.TempDir()
keysetPath := filepath.Join(dir, "keyset.json.enc")
f, err := os.Create(keysetPath)
if err != nil {
t.Fatalf("error creating file: %v", err)
}
defer f.Close()
jsonWriter := keyset.NewJSONWriter(f)
if err := kh.Write(jsonWriter, a); err != nil {
t.Fatalf("error writing enc keyset: %v", err)
}
signer, err := NewTinkSigner(context.TODO(), keysetPath, a)
if err != nil {
t.Fatalf("unexpected error creating Tink signer: %v", err)
}
// Expect signer and key handle's public keys match
if err := cryptoutils.EqualKeys(signer.Public(), khsigner.Public()); err != nil {
t.Fatalf("keys of signer and key handle do not match: %v", err)
}
// Failure: Unable to decrypt keyset
aeskh1, err := keyset.NewHandle(aead.AES256GCMKeyTemplate())
if err != nil {
t.Fatalf("error creating AEAD key handle: %v", err)
}
a1, err := aead.New(aeskh1)
if err != nil {
t.Fatalf("error creating AEAD key: %v", err)
}
_, err = NewTinkSigner(context.TODO(), keysetPath, a1)
if err == nil || !strings.Contains(err.Error(), "decryption failed") {
t.Fatalf("expected error decrypting keyset, got %v", err)
}
}
func TestKeyHandleToSignerECDSA(t *testing.T) {
supportedKeyTypes := []TestStruct{
{
keyTemplate: signature.ECDSAP256KeyWithoutPrefixTemplate(),
h: sha256.New(),
},
{
keyTemplate: signature.ECDSAP384KeyWithoutPrefixTemplate(),
h: sha512.New(),
},
{
keyTemplate: signature.ECDSAP521KeyWithoutPrefixTemplate(),
h: sha512.New(),
},
}
for _, kt := range supportedKeyTypes {
kh, err := keyset.NewHandle(kt.keyTemplate)
if err != nil {
t.Fatalf("error creating ECDSA key handle: %v", err)
}
// convert to crypto.Signer interface
signer, err := KeyHandleToSigner(kh)
if err != nil {
t.Fatalf("error converting ECDSA key handle to signer: %v", err)
}
msg := []byte("hello there")
// sign with key handle, verify with signer public key
tinkSigner, err := signature.NewSigner(kh)
if err != nil {
t.Fatalf("error creating tink signer: %v", err)
}
sig, err := tinkSigner.Sign(msg)
if err != nil {
t.Fatalf("error signing with tink signer: %v", err)
}
kt.h.Write(msg)
digest := kt.h.Sum(nil)
if !ecdsa.VerifyASN1(signer.Public().(*ecdsa.PublicKey), digest, sig) {
t.Fatalf("signature from tink signer did not match")
}
// sign with signer, verify with key handle
sig, err = ecdsa.SignASN1(rand.Reader, signer.(*ecdsa.PrivateKey), digest)
if err != nil {
t.Fatalf("error signing with crypto signer: %v", err)
}
pubkh, err := kh.Public()
if err != nil {
t.Fatalf("error fetching public key handle: %v", err)
}
v, err := signature.NewVerifier(pubkh)
if err != nil {
t.Fatalf("error creating tink verifier: %v", err)
}
if err := v.Verify(sig, msg); err != nil {
t.Fatalf("error verifying with tink verifier: %v", err)
}
}
}
func TestKeyHandleToSignerED25519(t *testing.T) {
kh, err := keyset.NewHandle(signature.ED25519KeyWithoutPrefixTemplate())
if err != nil {
t.Fatalf("error creating ED25519 key handle: %v", err)
}
// convert to crypto.Signer interface
signer, err := KeyHandleToSigner(kh)
if err != nil {
t.Fatalf("error converting ED25519 key handle to signer: %v", err)
}
msg := []byte("hello there")
// sign with key handle, verify with signer public key
tinkSigner, err := signature.NewSigner(kh)
if err != nil {
t.Fatalf("error creating tink signer: %v", err)
}
sig, err := tinkSigner.Sign(msg)
if err != nil {
t.Fatalf("error signing with tink signer: %v", err)
}
if !ed25519.Verify(signer.Public().(ed25519.PublicKey), msg, sig) {
t.Fatalf("signature from tink signer did not match")
}
// sign with signer, verify with key handle
sig = ed25519.Sign(signer.(ed25519.PrivateKey), msg)
if err != nil {
t.Fatalf("error signing with crypto signer: %v", err)
}
pubkh, err := kh.Public()
if err != nil {
t.Fatalf("error fetching public key handle: %v", err)
}
v, err := signature.NewVerifier(pubkh)
if err != nil {
t.Fatalf("error creating tink verifier: %v", err)
}
if err := v.Verify(sig, msg); err != nil {
t.Fatalf("error verifying with tink verifier: %v", err)
}
}
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