Add and register key creator function for XChaCha20-Poly1305 to the V…

…0 config

PiperOrigin-RevId: 717906170
Change-Id: I390537e848c28fdff9b2dac76309c1653f725c2b

aead/xchacha20poly1305/key.go

@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"fmt"
 
+	"github.com/tink-crypto/tink-go/v2/internal/internalapi"
 	"github.com/tink-crypto/tink-go/v2/internal/outputprefix"
 	"github.com/tink-crypto/tink-go/v2/key"
 	"github.com/tink-crypto/tink-go/v2/secretdata"
@@ -161,3 +162,22 @@ func (k *Key) Equal(other key.Key) bool {
 		k.idRequirement == that.idRequirement &&
 		k.keyBytes.Equal(that.keyBytes)
 }
+
+func createKey(p key.Parameters, idRequirement uint32) (key.Key, error) {
+	xChaCha20Poly1305Params, ok := p.(*Parameters)
+	if !ok {
+		return nil, fmt.Errorf("key is of type %T; needed %T", p, (*Parameters)(nil))
+	}
+	keyBytes, err := secretdata.NewBytesFromRand(uint32(32))
+	if err != nil {
+		return nil, err
+	}
+	return NewKey(keyBytes, idRequirement, xChaCha20Poly1305Params)
+}
+
+// KeyCreator returns a key creator function.
+//
+// It is *NOT* part of the public API.
+func KeyCreator(t internalapi.Token) func(p key.Parameters, idRequirement uint32) (key.Key, error) {
+	return createKey
+}

aead/xchacha20poly1305/key_test.go

@@ -18,9 +18,11 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/tink-crypto/tink-go/v2/aead/xchacha20poly1305"
 	"github.com/tink-crypto/tink-go/v2/core/cryptofmt"
 	"github.com/tink-crypto/tink-go/v2/insecuresecretdataaccess"
+	"github.com/tink-crypto/tink-go/v2/internal/internalapi"
 	"github.com/tink-crypto/tink-go/v2/secretdata"
 )
 
@@ -315,3 +317,28 @@ func TestKeyEqualReturnsFalseIfDifferent(t *testing.T) {
 		})
 	}
 }
+
+func TestKeyCreator(t *testing.T) {
+	keyCreator := xchacha20poly1305.KeyCreator(internalapi.Token{})
+	params, err := xchacha20poly1305.NewParameters(xchacha20poly1305.VariantTink)
+	if err != nil {
+		t.Fatalf("xchacha20poly1305.NewParameters() err = %v, want nil", err)
+	}
+
+	key, err := keyCreator(params, 123)
+	if err != nil {
+		t.Fatalf("keyCreator(%v, 123) err = %v, want nil", params, err)
+	}
+	xChaCha20Poly1305, ok := key.(*xchacha20poly1305.Key)
+	if !ok {
+		t.Fatalf("keyCreator(%v, 123) returned key of type %T, want %T", params, key, (*xchacha20poly1305.Key)(nil))
+	}
+
+	idRequirement, hasIDRequirement := xChaCha20Poly1305.IDRequirement()
+	if !hasIDRequirement || idRequirement != 123 {
+		t.Errorf("xChaCha20Poly1305.IDRequirement() (%v, %v), want (%v, %v)", idRequirement, hasIDRequirement, 123, true)
+	}
+	if diff := cmp.Diff(xChaCha20Poly1305.Parameters(), params); diff != "" {
+		t.Errorf("xChaCha20Poly1305.Parameters() diff (-want +got):\n%s", diff)
+	}
+}

internal/keygenconfig/v0.go

@@ -23,6 +23,7 @@ import (
 	"github.com/tink-crypto/tink-go/v2/aead/aesgcmsiv"
 	"github.com/tink-crypto/tink-go/v2/aead/chacha20poly1305"
 	"github.com/tink-crypto/tink-go/v2/aead/xaesgcm"
+	"github.com/tink-crypto/tink-go/v2/aead/xchacha20poly1305"
 	"github.com/tink-crypto/tink-go/v2/internal/internalapi"
 )
 
@@ -46,6 +47,9 @@ func mustCreateConfigV0() Config {
 	if err := config.RegisterKeyCreator(reflect.TypeFor[*xaesgcm.Parameters](), xaesgcm.KeyCreator(internalapi.Token{})); err != nil {
 		panic(fmt.Sprintf("keygenconfig: failed to register XAES-GCM: %v", err))
 	}
+	if err := config.RegisterKeyCreator(reflect.TypeFor[*xchacha20poly1305.Parameters](), xchacha20poly1305.KeyCreator(internalapi.Token{})); err != nil {
+		panic(fmt.Sprintf("keygenconfig: failed to register XChaCha20-Poly1305: %v", err))
+	}
 
 	return *config
 }

internal/keygenconfig/v0_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/tink-crypto/tink-go/v2/aead/aesgcmsiv"
 	"github.com/tink-crypto/tink-go/v2/aead/chacha20poly1305"
 	"github.com/tink-crypto/tink-go/v2/aead/xaesgcm"
+	"github.com/tink-crypto/tink-go/v2/aead/xchacha20poly1305"
 	"github.com/tink-crypto/tink-go/v2/internal/keygenconfig"
 	"github.com/tink-crypto/tink-go/v2/key"
 )
@@ -84,6 +85,15 @@ func mustCreateXAESGCMParams(t *testing.T, variant xaesgcm.Variant) *xaesgcm.Par
 	return params
 }
 
+func mustCreateXChaCha20Poly1305Params(t *testing.T, variant xchacha20poly1305.Variant) *xchacha20poly1305.Parameters {
+	t.Helper()
+	params, err := xchacha20poly1305.NewParameters(variant)
+	if err != nil {
+		t.Fatalf("xchacha20poly1305.NewParameters() err = %v, want nil", err)
+	}
+	return params
+}
+
 func tryCast[T any](k key.Key) error {
 	if _, ok := k.(T); !ok {
 		return fmt.Errorf("key is of type %T; want %T", k, (*T)(nil))
@@ -159,6 +169,18 @@ func TestV0(t *testing.T) {
 			idRequirement: 0,
 			tryCast:       tryCast[*xaesgcm.Key],
 		},
+		{
+			name:          "XChaCha20Poly1305-TINK",
+			p:             mustCreateXChaCha20Poly1305Params(t, xchacha20poly1305.VariantTink),
+			idRequirement: 123,
+			tryCast:       tryCast[*xchacha20poly1305.Key],
+		},
+		{
+			name:          "XChaCha20Poly1305-NO_PREFIX",
+			p:             mustCreateXChaCha20Poly1305Params(t, xchacha20poly1305.VariantNoPrefix),
+			idRequirement: 0,
+			tryCast:       tryCast[*xchacha20poly1305.Key],
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			key, err := config.CreateKey(tc.p, tc.idRequirement)