Merge branch 'v5' into otel

# Conflicts:
#	go.sum
#	internal/cmd/serve.go
#	internal/http/http.go

internal/client/signer/local.go

@@ -0,0 +1,34 @@
+package signer
+
+import (
+	"context"
+	"io"
+	"strings"
+)
+
+type Signer interface {
+	Sign(data io.Reader) ([]byte, error)
+	GetPublicKey(format string) ([]byte, error)
+}
+
+type LocalSigner struct {
+	Signer
+}
+
+func (s *LocalSigner) Sign(ctx context.Context, data string) (string, error) {
+	signed, err := s.Signer.Sign(strings.NewReader(data))
+	if err != nil {
+		return "", err
+	}
+
+	return string(signed), nil
+}
+
+func (s *LocalSigner) GetPublicKey(ctx context.Context, format string) (string, error) {
+	publicKey, err := s.Signer.GetPublicKey(format)
+	if err != nil {
+		return "", err
+	}
+
+	return string(publicKey), nil
+}

internal/client/signer/local_test.go

@@ -0,0 +1,104 @@
+package signer
+
+import (
+	"context"
+	"errors"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+)
+
+type SignerMock struct {
+	mock.Mock
+}
+
+func (m *SignerMock) Sign(data io.Reader) ([]byte, error) {
+	args := m.Called(data)
+	var result []byte
+	if casted, ok := args.Get(0).([]byte); ok {
+		result = casted
+	}
+
+	return result, args.Error(1)
+}
+
+func (m *SignerMock) GetPublicKey(format string) ([]byte, error) {
+	args := m.Called(format)
+	var result []byte
+	if casted, ok := args.Get(0).([]byte); ok {
+		result = casted
+	}
+
+	return result, args.Error(1)
+}
+
+type LocalSignerServiceTestSuite struct {
+	suite.Suite
+
+	Service *LocalSigner
+
+	Signer *SignerMock
+}
+
+func (t *LocalSignerServiceTestSuite) SetupSubTest() {
+	t.Signer = &SignerMock{}
+
+	t.Service = &LocalSigner{
+		Signer: t.Signer,
+	}
+}
+
+func (t *LocalSignerServiceTestSuite) TearDownSubTest() {
+	t.Signer.AssertExpectations(t.T())
+}
+
+func (t *LocalSignerServiceTestSuite) TestSign() {
+	t.Run("successfully sign", func() {
+		signature := []byte("mock signature")
+		t.Signer.On("Sign", mock.Anything).Return(signature, nil).Run(func(args mock.Arguments) {
+			r, _ := io.ReadAll(args.Get(0).(io.Reader))
+			t.Equal([]byte("mock body to sign"), r)
+		})
+
+		result, err := t.Service.Sign(context.Background(), "mock body to sign")
+		t.NoError(err)
+		t.Equal(string(signature), result)
+	})
+
+	t.Run("handle error during sign", func() {
+		expectedErr := errors.New("mock error")
+		t.Signer.On("Sign", mock.Anything).Return(nil, expectedErr)
+
+		result, err := t.Service.Sign(context.Background(), "mock body to sign")
+		t.Error(err)
+		t.Same(expectedErr, err)
+		t.Empty(result)
+	})
+}
+
+func (t *LocalSignerServiceTestSuite) TestGetPublicKey() {
+	t.Run("successfully get", func() {
+		publicKey := []byte("mock public key")
+		t.Signer.On("GetPublicKey", "pem").Return(publicKey, nil)
+
+		result, err := t.Service.GetPublicKey(context.Background(), "pem")
+		t.NoError(err)
+		t.Equal(string(publicKey), result)
+	})
+
+	t.Run("handle error", func() {
+		expectedErr := errors.New("mock error")
+		t.Signer.On("GetPublicKey", "pem").Return(nil, expectedErr)
+
+		result, err := t.Service.GetPublicKey(context.Background(), "pem")
+		t.Error(err)
+		t.Same(expectedErr, err)
+		t.Empty(result)
+	})
+}
+
+func TestLocalSignerService(t *testing.T) {
+	suite.Run(t, new(LocalSignerServiceTestSuite))
+}

internal/cmd/serve.go

@@ -7,6 +7,7 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
+	"ely.by/chrly/internal/di"
 	"ely.by/chrly/internal/http"
 	"ely.by/chrly/internal/otel"
 )
@@ -15,7 +16,7 @@ var serveCmd = &cobra.Command{
 	Use:   "serve",
 	Short: "Starts HTTP handler for the skins system",
 	RunE: func(cmd *cobra.Command, args []string) error {
-		return startServer("skinsystem", "api")
+		return startServer(di.ModuleSkinsystem, di.ModuleProfiles, di.ModuleSigner)
 	},
 }
 

internal/cmd/token.go

@@ -9,8 +9,10 @@ import (
 )
 
 var tokenCmd = &cobra.Command{
-	Use:   "token",
-	Short: "Creates a new token, which allows to interact with Chrly API",
+	Use:       "token scope1 ...",
+	Example:   "token profiles sign",
+	Short:     "Creates a new token, which allows to interact with Chrly API",
+	ValidArgs: []string{string(security.ProfilesScope), string(security.SignScope)},
 	RunE: func(cmd *cobra.Command, args []string) error {
 		container := shouldGetContainer()
 		var auth *security.Jwt
@@ -19,7 +21,12 @@ var tokenCmd = &cobra.Command{
 			return err
 		}
 
-		token, err := auth.NewToken(security.ProfileScope)
+		scopes := make([]security.Scope, len(args))
+		for i := range args {
+			scopes[i] = security.Scope(args[i])
+		}
+
+		token, err := auth.NewToken(scopes...)
 		if err != nil {
 			return fmt.Errorf("Unable to create a new token. The error is %v\n", err)
 		}

internal/di/config.go

@@ -6,9 +6,5 @@ import (
 )
 
 var configDiOptions = di.Options(
-	di.Provide(newConfig),
+	di.Provide(viper.GetViper),
 )
-
-func newConfig() *viper.Viper {
-	return viper.GetViper()
-}

internal/di/handlers.go

@@ -12,12 +12,18 @@ import (
 	"go.opentelemetry.io/contrib/instrumentation/github.com/gorilla/mux/otelmux"
 
 	. "ely.by/chrly/internal/http"
+	"ely.by/chrly/internal/security"
 )
 
+const ModuleSkinsystem = "skinsystem"
+const ModuleProfiles = "profiles"
+const ModuleSigner = "signer"
+
 var handlersDiOptions = di.Options(
 	di.Provide(newHandlerFactory, di.As(new(http.Handler))),
-	di.Provide(newSkinsystemHandler, di.WithName("skinsystem")),
-	di.Provide(newApiHandler, di.WithName("api")),
+	di.Provide(newSkinsystemHandler, di.WithName(ModuleSkinsystem)),
+	di.Provide(newProfilesApiHandler, di.WithName(ModuleProfiles)),
+	di.Provide(newSignerApiHandler, di.WithName(ModuleSigner)),
 )
 
 func newHandlerFactory(
@@ -31,8 +37,8 @@ func newHandlerFactory(
 	// if you set an empty prefix. Since the main application should be mounted at the root prefix,
 	// we use it as the base router
 	var router *mux.Router
-	if slices.Contains(enabledModules, "skinsystem") {
-		if err := container.Resolve(&router, di.Name("skinsystem")); err != nil {
+	if slices.Contains(enabledModules, ModuleSkinsystem) {
+		if err := container.Resolve(&router, di.Name(ModuleSkinsystem)); err != nil {
 			return nil, err
 		}
 	} else {
@@ -43,9 +49,9 @@ func newHandlerFactory(
 	router.Use(otelmux.Middleware("chrly"))
 	router.NotFoundHandler = http.HandlerFunc(NotFoundHandler)
 
-	if slices.Contains(enabledModules, "api") {
-		var apiRouter *mux.Router
-		if err := container.Resolve(&apiRouter, di.Name("api")); err != nil {
+	if slices.Contains(enabledModules, ModuleProfiles) {
+		var profilesApiRouter *mux.Router
+		if err := container.Resolve(&profilesApiRouter, di.Name(ModuleProfiles)); err != nil {
 			return nil, err
 		}
 
@@ -54,9 +60,29 @@ func newHandlerFactory(
 			return nil, err
 		}
 
-		apiRouter.Use(CreateAuthenticationMiddleware(authenticator))
+		profilesApiRouter.Use(NewAuthenticationMiddleware(authenticator, security.ProfilesScope))
 
-		mount(router, "/api", apiRouter)
+		mount(router, "/api/profiles", profilesApiRouter)
+	}
+
+	if slices.Contains(enabledModules, ModuleSigner) {
+		var signerApiRouter *mux.Router
+		if err := container.Resolve(&signerApiRouter, di.Name(ModuleSigner)); err != nil {
+			return nil, err
+		}
+
+		var authenticator Authenticator
+		if err := container.Resolve(&authenticator); err != nil {
+			return nil, err
+		}
+
+		authMiddleware := NewAuthenticationMiddleware(authenticator, security.SignScope)
+		conditionalAuth := NewConditionalMiddleware(func(req *http.Request) bool {
+			return req.Method != "GET"
+		}, authMiddleware)
+		signerApiRouter.Use(conditionalAuth)
+
+		mount(router, "/api/signer", signerApiRouter)
 	}
 
 	// Resolve health checkers last, because all the services required by the application
@@ -81,25 +107,31 @@ func newHandlerFactory(
 func newSkinsystemHandler(
 	config *viper.Viper,
 	profilesProvider ProfilesProvider,
-	texturesSigner TexturesSigner,
+	texturesSigner SignerService,
 ) *mux.Router {
 	config.SetDefault("textures.extra_param_name", "chrly")
 	config.SetDefault("textures.extra_param_value", "how do you tame a horse in Minecraft?")
 
 	return (&Skinsystem{
 		ProfilesProvider:        profilesProvider,
-		TexturesSigner:          texturesSigner,
+		SignerService:           texturesSigner,
 		TexturesExtraParamName:  config.GetString("textures.extra_param_name"),
 		TexturesExtraParamValue: config.GetString("textures.extra_param_value"),
 	}).Handler()
 }
 
-func newApiHandler(profilesManager ProfilesManager) *mux.Router {
-	return (&Api{
+func newProfilesApiHandler(profilesManager ProfilesManager) *mux.Router {
+	return (&ProfilesApi{
 		ProfilesManager: profilesManager,
 	}).Handler()
 }
 
+func newSignerApiHandler(signer Signer) *mux.Router {
+	return (&SignerApi{
+		Signer: signer,
+	}).Handler()
+}
+
 func mount(router *mux.Router, path string, handler http.Handler) {
 	router.PathPrefix(path).Handler(
 		http.StripPrefix(

internal/di/security.go

@@ -4,10 +4,11 @@ import (
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
-	"encoding/base64"
 	"encoding/pem"
-	"strings"
+	"errors"
+	"log/slog"
 
+	"ely.by/chrly/internal/client/signer"
 	"ely.by/chrly/internal/http"
 	"ely.by/chrly/internal/security"
 
@@ -16,41 +17,43 @@ import (
 )
 
 var securityDiOptions = di.Options(
-	di.Provide(newTexturesSigner,
-		di.As(new(http.TexturesSigner)),
+	di.Provide(newSigner,
+		di.As(new(http.Signer)),
+		di.As(new(signer.Signer)),
 	),
+	di.Provide(newSignerService),
 )
 
-func newTexturesSigner(config *viper.Viper) (*security.Signer, error) {
+func newSigner(config *viper.Viper) (*security.Signer, error) {
+	var privateKey *rsa.PrivateKey
+	var err error
+
 	keyStr := config.GetString("chrly.signing.key")
 	if keyStr == "" {
-		// TODO: log a message about the generated signing key and the way to specify it permanently
-		privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
+		privateKey, err = rsa.GenerateKey(rand.Reader, 2048)
 		if err != nil {
 			return nil, err
 		}
 
-		return security.NewSigner(privateKey), nil
-	}
-
-	var keyBytes []byte
-	if strings.HasPrefix(keyStr, "base64:") {
-		base64Value := keyStr[7:]
-		decodedKey, err := base64.URLEncoding.DecodeString(base64Value)
-		if err != nil {
-			return nil, err
-		}
-
-		keyBytes = decodedKey
+		slog.Warn("A private signing key has been generated. To make it permanent, specify the valid RSA private key in the config parameter chrly.signing.key")
 	} else {
-		keyBytes = []byte(keyStr)
-	}
+		keyBytes := []byte(keyStr)
+		rawPem, _ := pem.Decode(keyBytes)
+		if rawPem == nil {
+			return nil, errors.New("unable to decode pem key")
+		}
 
-	rawPem, _ := pem.Decode(keyBytes)
-	privateKey, err := x509.ParsePKCS1PrivateKey(rawPem.Bytes)
-	if err != nil {
-		return nil, err
+		privateKey, err = x509.ParsePKCS1PrivateKey(rawPem.Bytes)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	return security.NewSigner(privateKey), nil
 }
+
+func newSignerService(s signer.Signer) http.SignerService {
+	return &signer.LocalSigner{
+		Signer: s,
+	}
+}

internal/http/http.go

@@ -3,7 +3,6 @@ package http
 import (
 	"context"
 	"encoding/json"
-	"log/slog"
 	"net/http"
 	"time"
 
@@ -11,12 +10,10 @@ import (
 	"github.com/mono83/slf"
 	"github.com/mono83/slf/wd"
 
-	"ely.by/chrly/internal/version"
+	"ely.by/chrly/internal/security"
 )
 
 func StartServer(ctx context.Context, server *http.Server, logger slf.Logger) {
-	slog.Debug("Chrly :v (:c)", slog.String("v", version.Version()), slog.String("c", version.Commit()))
-
 	srvErr := make(chan error, 1)
 	go func() {
 		logger.Info("Starting the server, HTTP on: :addr", wd.StringParam("addr", server.Addr))
@@ -40,15 +37,13 @@ func StartServer(ctx context.Context, server *http.Server, logger slf.Logger) {
 }
 
 type Authenticator interface {
-	Authenticate(req *http.Request) error
+	Authenticate(req *http.Request, scope security.Scope) error
 }
 
-// The current middleware implementation doesn't check the scope assigned to the token.
-// For now there is only one scope and at this moment I don't want to spend time on it
-func CreateAuthenticationMiddleware(checker Authenticator) mux.MiddlewareFunc {
+func NewAuthenticationMiddleware(authenticator Authenticator, scope security.Scope) mux.MiddlewareFunc {
 	return func(handler http.Handler) http.Handler {
 		return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
-			err := checker.Authenticate(req)
+			err := authenticator.Authenticate(req, scope)
 			if err != nil {
 				apiForbidden(resp, err.Error())
 				return
@@ -59,6 +54,18 @@ func CreateAuthenticationMiddleware(checker Authenticator) mux.MiddlewareFunc {
 	}
 }
 
+func NewConditionalMiddleware(cond func(req *http.Request) bool, m mux.MiddlewareFunc) mux.MiddlewareFunc {
+	return func(handler http.Handler) http.Handler {
+		return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+			if cond(req) {
+				handler = m.Middleware(handler)
+			}
+
+			handler.ServeHTTP(resp, req)
+		})
+	}
+}
+
 func NotFoundHandler(response http.ResponseWriter, _ *http.Request) {
 	data, _ := json.Marshal(map[string]string{
 		"status":  "404",
@@ -73,7 +80,7 @@ func NotFoundHandler(response http.ResponseWriter, _ *http.Request) {
 func apiBadRequest(resp http.ResponseWriter, errorsPerField map[string][]string) {
 	resp.WriteHeader(http.StatusBadRequest)
 	resp.Header().Set("Content-Type", "application/json")
-	result, _ := json.Marshal(map[string]interface{}{
+	result, _ := json.Marshal(map[string]any{
 		"errors": errorsPerField,
 	})
 	_, _ = resp.Write(result)
@@ -90,7 +97,7 @@ func apiServerError(resp http.ResponseWriter, err error) {
 func apiForbidden(resp http.ResponseWriter, reason string) {
 	resp.WriteHeader(http.StatusForbidden)
 	resp.Header().Set("Content-Type", "application/json")
-	result, _ := json.Marshal(map[string]interface{}{
+	result, _ := json.Marshal(map[string]any{
 		"error": reason,
 	})
 	_, _ = resp.Write(result)

internal/http/http_test.go

@@ -2,34 +2,35 @@ package http
 
 import (
 	"errors"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
-	testify "github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	testify "github.com/stretchr/testify/require"
+
+	"ely.by/chrly/internal/security"
 )
 
 type authCheckerMock struct {
 	mock.Mock
 }
 
-func (m *authCheckerMock) Authenticate(req *http.Request) error {
-	args := m.Called(req)
-	return args.Error(0)
+func (m *authCheckerMock) Authenticate(req *http.Request, scope security.Scope) error {
+	return m.Called(req, scope).Error(0)
 }
 
-func TestCreateAuthenticationMiddleware(t *testing.T) {
+func TestAuthenticationMiddleware(t *testing.T) {
 	t.Run("pass", func(t *testing.T) {
-		req := httptest.NewRequest("GET", "http://example.com", nil)
+		req := httptest.NewRequest("GET", "https://example.com", nil)
 		resp := httptest.NewRecorder()
 
 		auth := &authCheckerMock{}
-		auth.On("Authenticate", req).Once().Return(nil)
+		auth.On("Authenticate", req, security.Scope("mock")).Once().Return(nil)
 
 		isHandlerCalled := false
-		middlewareFunc := CreateAuthenticationMiddleware(auth)
+		middlewareFunc := NewAuthenticationMiddleware(auth, "mock")
 		middlewareFunc.Middleware(http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
 			isHandlerCalled = true
 		})).ServeHTTP(resp, req)
@@ -40,21 +41,21 @@ func TestCreateAuthenticationMiddleware(t *testing.T) {
 	})
 
 	t.Run("fail", func(t *testing.T) {
-		req := httptest.NewRequest("GET", "http://example.com", nil)
+		req := httptest.NewRequest("GET", "https://example.com", nil)
 		resp := httptest.NewRecorder()
 
 		auth := &authCheckerMock{}
-		auth.On("Authenticate", req).Once().Return(errors.New("error reason"))
+		auth.On("Authenticate", req, security.Scope("mock")).Once().Return(errors.New("error reason"))
 
 		isHandlerCalled := false
-		middlewareFunc := CreateAuthenticationMiddleware(auth)
+		middlewareFunc := NewAuthenticationMiddleware(auth, "mock")
 		middlewareFunc.Middleware(http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
 			isHandlerCalled = true
 		})).ServeHTTP(resp, req)
 
 		testify.False(t, isHandlerCalled, "Handler shouldn't be called")
 		testify.Equal(t, 403, resp.Code)
-		body, _ := ioutil.ReadAll(resp.Body)
+		body, _ := io.ReadAll(resp.Body)
 		testify.JSONEq(t, `{
 			"error": "error reason"
 		}`, string(body))
@@ -63,10 +64,56 @@ func TestCreateAuthenticationMiddleware(t *testing.T) {
 	})
 }
 
+func TestConditionalMiddleware(t *testing.T) {
+	t.Run("true", func(t *testing.T) {
+		req := httptest.NewRequest("GET", "https://example.com", nil)
+		resp := httptest.NewRecorder()
+
+		isNestedMiddlewareCalled := false
+		isHandlerCalled := false
+		NewConditionalMiddleware(
+			func(req *http.Request) bool {
+				return true
+			},
+			func(handler http.Handler) http.Handler {
+				isNestedMiddlewareCalled = true
+				return handler
+			},
+		).Middleware(http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+			isHandlerCalled = true
+		})).ServeHTTP(resp, req)
+
+		testify.True(t, isNestedMiddlewareCalled, "Nested middleware wasn't called")
+		testify.True(t, isHandlerCalled, "Handler wasn't called from the middleware")
+	})
+
+	t.Run("false", func(t *testing.T) {
+		req := httptest.NewRequest("GET", "https://example.com", nil)
+		resp := httptest.NewRecorder()
+
+		isNestedMiddlewareCalled := false
+		isHandlerCalled := false
+		NewConditionalMiddleware(
+			func(req *http.Request) bool {
+				return false
+			},
+			func(handler http.Handler) http.Handler {
+				isNestedMiddlewareCalled = true
+				return handler
+			},
+		).Middleware(http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+			isHandlerCalled = true
+		})).ServeHTTP(resp, req)
+
+		testify.False(t, isNestedMiddlewareCalled, "Nested middleware shouldn't be called")
+		testify.True(t, isHandlerCalled, "Handler wasn't called from the middleware")
+	})
+}
+
 func TestNotFoundHandler(t *testing.T) {
 	assert := testify.New(t)
 
-	req := httptest.NewRequest("GET", "http://example.com", nil)
+	req := httptest.NewRequest("GET", "https://example.com", nil)
 	w := httptest.NewRecorder()
 
 	NotFoundHandler(w, req)
@@ -74,7 +121,7 @@ func TestNotFoundHandler(t *testing.T) {
 	resp := w.Result()
 	assert.Equal(404, resp.StatusCode)
 	assert.Equal("application/json", resp.Header.Get("Content-Type"))
-	response, _ := ioutil.ReadAll(resp.Body)
+	response, _ := io.ReadAll(resp.Body)
 	assert.JSONEq(`{
 		"status": "404",
 		"message": "Not Found"

internal/http/profiles.go

@@ -17,19 +17,19 @@ type ProfilesManager interface {
 	RemoveProfileByUuid(ctx context.Context, uuid string) error
 }
 
-type Api struct {
+type ProfilesApi struct {
 	ProfilesManager
 }
 
-func (ctx *Api) Handler() *mux.Router {
+func (ctx *ProfilesApi) Handler() *mux.Router {
 	router := mux.NewRouter().StrictSlash(true)
-	router.HandleFunc("/profiles", ctx.postProfileHandler).Methods(http.MethodPost)
-	router.HandleFunc("/profiles/{uuid}", ctx.deleteProfileByUuidHandler).Methods(http.MethodDelete)
+	router.HandleFunc("/", ctx.postProfileHandler).Methods(http.MethodPost)
+	router.HandleFunc("/{uuid}", ctx.deleteProfileByUuidHandler).Methods(http.MethodDelete)
 
 	return router
 }
 
-func (ctx *Api) postProfileHandler(resp http.ResponseWriter, req *http.Request) {
+func (ctx *ProfilesApi) postProfileHandler(resp http.ResponseWriter, req *http.Request) {
 	err := req.ParseForm()
 	if err != nil {
 		apiBadRequest(resp, map[string][]string{
@@ -63,7 +63,7 @@ func (ctx *Api) postProfileHandler(resp http.ResponseWriter, req *http.Request)
 	resp.WriteHeader(http.StatusCreated)
 }
 
-func (ctx *Api) deleteProfileByUuidHandler(resp http.ResponseWriter, req *http.Request) {
+func (ctx *ProfilesApi) deleteProfileByUuidHandler(resp http.ResponseWriter, req *http.Request) {
 	uuid := mux.Vars(req)["uuid"]
 	err := ctx.ProfilesManager.RemoveProfileByUuid(req.Context(), uuid)
 	if err != nil {

internal/http/profiles_test.go

@@ -30,26 +30,26 @@ func (m *ProfilesManagerMock) RemoveProfileByUuid(ctx context.Context, uuid stri
 	return m.Called(ctx, uuid).Error(0)
 }
 
-type ApiTestSuite struct {
+type ProfilesTestSuite struct {
 	suite.Suite
 
-	App *Api
+	App *ProfilesApi
 
 	ProfilesManager *ProfilesManagerMock
 }
 
-func (t *ApiTestSuite) SetupSubTest() {
+func (t *ProfilesTestSuite) SetupSubTest() {
 	t.ProfilesManager = &ProfilesManagerMock{}
-	t.App = &Api{
+	t.App = &ProfilesApi{
 		ProfilesManager: t.ProfilesManager,
 	}
 }
 
-func (t *ApiTestSuite) TearDownSubTest() {
+func (t *ProfilesTestSuite) TearDownSubTest() {
 	t.ProfilesManager.AssertExpectations(t.T())
 }
 
-func (t *ApiTestSuite) TestPostProfile() {
+func (t *ProfilesTestSuite) TestPostProfile() {
 	t.Run("successfully post profile", func() {
 		t.ProfilesManager.On("PersistProfile", mock.Anything, &db.Profile{
 			Uuid:            "0f657aa8-bfbe-415d-b700-5750090d3af3",
@@ -61,7 +61,7 @@ func (t *ApiTestSuite) TestPostProfile() {
 			MojangSignature: "bW9jawo=",
 		}).Once().Return(nil)
 
-		req := httptest.NewRequest("POST", "http://chrly/profiles", bytes.NewBufferString(url.Values{
+		req := httptest.NewRequest("POST", "http://chrly/", bytes.NewBufferString(url.Values{
 			"uuid":            {"0f657aa8-bfbe-415d-b700-5750090d3af3"},
 			"username":        {"mock_username"},
 			"skinUrl":         {"https://example.com/skin.png"},
@@ -82,7 +82,7 @@ func (t *ApiTestSuite) TestPostProfile() {
 	})
 
 	t.Run("handle malformed body", func() {
-		req := httptest.NewRequest("POST", "http://chrly/profiles", strings.NewReader("invalid;=url?encoded_string"))
+		req := httptest.NewRequest("POST", "http://chrly/", strings.NewReader("invalid;=url?encoded_string"))
 		req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 		w := httptest.NewRecorder()
 
@@ -107,7 +107,7 @@ func (t *ApiTestSuite) TestPostProfile() {
 			},
 		})
 
-		req := httptest.NewRequest("POST", "http://chrly/profiles", strings.NewReader(""))
+		req := httptest.NewRequest("POST", "http://chrly/", strings.NewReader(""))
 		req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 		w := httptest.NewRecorder()
 
@@ -129,7 +129,7 @@ func (t *ApiTestSuite) TestPostProfile() {
 	t.Run("receive other error", func() {
 		t.ProfilesManager.On("PersistProfile", mock.Anything, mock.Anything).Once().Return(errors.New("mock error"))
 
-		req := httptest.NewRequest("POST", "http://chrly/profiles", strings.NewReader(""))
+		req := httptest.NewRequest("POST", "http://chrly/", strings.NewReader(""))
 		req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
 		w := httptest.NewRecorder()
 
@@ -140,11 +140,11 @@ func (t *ApiTestSuite) TestPostProfile() {
 	})
 }
 
-func (t *ApiTestSuite) TestDeleteProfileByUuid() {
+func (t *ProfilesTestSuite) TestDeleteProfileByUuid() {
 	t.Run("successfully delete", func() {
 		t.ProfilesManager.On("RemoveProfileByUuid", mock.Anything, "0f657aa8-bfbe-415d-b700-5750090d3af3").Once().Return(nil)
 
-		req := httptest.NewRequest("DELETE", "http://chrly/profiles/0f657aa8-bfbe-415d-b700-5750090d3af3", nil)
+		req := httptest.NewRequest("DELETE", "http://chrly/0f657aa8-bfbe-415d-b700-5750090d3af3", nil)
 		w := httptest.NewRecorder()
 
 		t.App.Handler().ServeHTTP(w, req)
@@ -158,7 +158,7 @@ func (t *ApiTestSuite) TestDeleteProfileByUuid() {
 	t.Run("error from manager", func() {
 		t.ProfilesManager.On("RemoveProfileByUuid", mock.Anything, mock.Anything).Return(errors.New("mock error"))
 
-		req := httptest.NewRequest("DELETE", "http://chrly/profiles/0f657aa8-bfbe-415d-b700-5750090d3af3", nil)
+		req := httptest.NewRequest("DELETE", "http://chrly/0f657aa8-bfbe-415d-b700-5750090d3af3", nil)
 		w := httptest.NewRecorder()
 
 		t.App.Handler().ServeHTTP(w, req)
@@ -168,6 +168,6 @@ func (t *ApiTestSuite) TestDeleteProfileByUuid() {
 	})
 }
 
-func TestApi(t *testing.T) {
-	suite.Run(t, new(ApiTestSuite))
+func TestProfilesApi(t *testing.T) {
+	suite.Run(t, new(ProfilesTestSuite))
 }

internal/http/signer.go

@@ -0,0 +1,60 @@
+package http
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+type Signer interface {
+	Sign(data io.Reader) ([]byte, error)
+	GetPublicKey(format string) ([]byte, error)
+}
+
+type SignerApi struct {
+	Signer
+}
+
+func (s *SignerApi) Handler() *mux.Router {
+	router := mux.NewRouter().StrictSlash(true)
+	router.HandleFunc("/", s.signHandler).Methods(http.MethodPost)
+	router.HandleFunc("/public-key.{format:(?:pem|der)}", s.getPublicKeyHandler).Methods(http.MethodGet)
+
+	return router
+}
+
+func (s *SignerApi) signHandler(resp http.ResponseWriter, req *http.Request) {
+	signature, err := s.Signer.Sign(req.Body)
+	if err != nil {
+		apiServerError(resp, fmt.Errorf("unable to sign the value: %w", err))
+		return
+	}
+
+	resp.Header().Set("Content-Type", "application/octet-stream+base64")
+
+	buf := make([]byte, base64.StdEncoding.EncodedLen(len(signature)))
+	base64.StdEncoding.Encode(buf, signature)
+	_, _ = resp.Write(buf)
+}
+
+func (s *SignerApi) getPublicKeyHandler(resp http.ResponseWriter, req *http.Request) {
+	format := mux.Vars(req)["format"]
+	publicKey, err := s.Signer.GetPublicKey(format)
+	if err != nil {
+		apiServerError(resp, fmt.Errorf("unable to retrieve public key: %w", err))
+		return
+	}
+
+	if format == "pem" {
+		resp.Header().Set("Content-Type", "application/x-pem-file")
+		resp.Header().Set("Content-Disposition", `attachment; filename="yggdrasil_session_pubkey.pem"`)
+	} else {
+		resp.Header().Set("Content-Type", "application/octet-stream")
+		resp.Header().Set("Content-Disposition", `attachment; filename="yggdrasil_session_pubkey.der"`)
+	}
+
+	_, _ = resp.Write(publicKey)
+}

internal/http/signer_test.go

@@ -0,0 +1,146 @@
+package http
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+)
+
+type SignerMock struct {
+	mock.Mock
+}
+
+func (m *SignerMock) Sign(data io.Reader) ([]byte, error) {
+	args := m.Called(data)
+	var result []byte
+	if casted, ok := args.Get(0).([]byte); ok {
+		result = casted
+	}
+
+	return result, args.Error(1)
+}
+
+func (m *SignerMock) GetPublicKey(format string) ([]byte, error) {
+	args := m.Called(format)
+	var result []byte
+	if casted, ok := args.Get(0).([]byte); ok {
+		result = casted
+	}
+
+	return result, args.Error(1)
+}
+
+type SignerApiTestSuite struct {
+	suite.Suite
+
+	App *SignerApi
+
+	Signer *SignerMock
+}
+
+func (t *SignerApiTestSuite) SetupSubTest() {
+	t.Signer = &SignerMock{}
+
+	t.App = &SignerApi{
+		Signer: t.Signer,
+	}
+}
+
+func (t *SignerApiTestSuite) TearDownSubTest() {
+	t.Signer.AssertExpectations(t.T())
+}
+
+func (t *SignerApiTestSuite) TestSign() {
+	t.Run("successfully sign", func() {
+		signature := []byte("mock signature")
+		t.Signer.On("Sign", mock.Anything).Return(signature, nil).Run(func(args mock.Arguments) {
+			buf := &bytes.Buffer{}
+			_, _ = io.Copy(buf, args.Get(0).(io.Reader))
+			r, _ := io.ReadAll(buf)
+
+			t.Equal([]byte("mock body to sign"), r)
+		})
+
+		req := httptest.NewRequest("POST", "http://chrly/", strings.NewReader("mock body to sign"))
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusOK, result.StatusCode)
+		t.Equal("application/octet-stream+base64", result.Header.Get("Content-Type"))
+		body, _ := io.ReadAll(result.Body)
+		t.Equal([]byte{0x62, 0x57, 0x39, 0x6a, 0x61, 0x79, 0x42, 0x7a, 0x61, 0x57, 0x64, 0x75, 0x59, 0x58, 0x52, 0x31, 0x63, 0x6d, 0x55, 0x3d}, body)
+	})
+
+	t.Run("handle error during sign", func() {
+		t.Signer.On("Sign", mock.Anything).Return(nil, errors.New("mock error"))
+
+		req := httptest.NewRequest("POST", "http://chrly/", strings.NewReader("mock body to sign"))
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusInternalServerError, result.StatusCode)
+	})
+}
+
+func (t *SignerApiTestSuite) TestGetPublicKey() {
+	t.Run("in pem format", func() {
+		publicKey := []byte("mock public key in pem format")
+		t.Signer.On("GetPublicKey", "pem").Return(publicKey, nil)
+
+		req := httptest.NewRequest("GET", "http://chrly/public-key.pem", nil)
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusOK, result.StatusCode)
+		t.Equal("application/x-pem-file", result.Header.Get("Content-Type"))
+		t.Equal(`attachment; filename="yggdrasil_session_pubkey.pem"`, result.Header.Get("Content-Disposition"))
+		body, _ := io.ReadAll(result.Body)
+		t.Equal(publicKey, body)
+	})
+
+	t.Run("in der format", func() {
+		publicKey := []byte("mock public key in der format")
+		t.Signer.On("GetPublicKey", "der").Return(publicKey, nil)
+
+		req := httptest.NewRequest("GET", "http://chrly/public-key.der", nil)
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusOK, result.StatusCode)
+		t.Equal("application/octet-stream", result.Header.Get("Content-Type"))
+		t.Equal(`attachment; filename="yggdrasil_session_pubkey.der"`, result.Header.Get("Content-Disposition"))
+		body, _ := io.ReadAll(result.Body)
+		t.Equal(publicKey, body)
+	})
+
+	t.Run("handle error", func() {
+		t.Signer.On("GetPublicKey", "pem").Return(nil, errors.New("mock error"))
+
+		req := httptest.NewRequest("GET", "http://chrly/public-key.pem", nil)
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusInternalServerError, result.StatusCode)
+	})
+}
+
+func TestSignerApi(t *testing.T) {
+	suite.Run(t, new(SignerApiTestSuite))
+}

internal/http/skinsystem.go

@@ -2,12 +2,10 @@ package http
 
 import (
 	"context"
-	"crypto/rsa"
-	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
-	"encoding/pem"
 	"fmt"
+	"io"
 	"net/http"
 	"strings"
 	"time"
@@ -25,40 +23,39 @@ type ProfilesProvider interface {
 	FindProfileByUsername(ctx context.Context, username string, allowProxy bool) (*db.Profile, error)
 }
 
-// TexturesSigner uses context because in the future we may separate this logic into a separate microservice
-type TexturesSigner interface {
-	SignTextures(ctx context.Context, textures string) (string, error)
-	GetPublicKey(ctx context.Context) (*rsa.PublicKey, error)
+// SignerService uses context because in the future we may separate this logic as an external microservice
+type SignerService interface {
+	Sign(ctx context.Context, data string) (string, error)
+	GetPublicKey(ctx context.Context, format string) (string, error)
 }
 
 type Skinsystem struct {
 	ProfilesProvider
-	TexturesSigner
+	SignerService
 	TexturesExtraParamName  string
 	TexturesExtraParamValue string
 }
 
-func (ctx *Skinsystem) Handler() *mux.Router {
+func (s *Skinsystem) Handler() *mux.Router {
 	router := mux.NewRouter().StrictSlash(true)
 
-	router.HandleFunc("/skins/{username}", ctx.skinHandler).Methods(http.MethodGet)
-	router.HandleFunc("/cloaks/{username}", ctx.capeHandler).Methods(http.MethodGet)
+	router.HandleFunc("/skins/{username}", s.skinHandler).Methods(http.MethodGet)
+	router.HandleFunc("/cloaks/{username}", s.capeHandler).Methods(http.MethodGet)
 	// TODO: alias /capes/{username}?
-	router.HandleFunc("/textures/{username}", ctx.texturesHandler).Methods(http.MethodGet)
-	router.HandleFunc("/textures/signed/{username}", ctx.signedTexturesHandler).Methods(http.MethodGet)
-	router.HandleFunc("/profile/{username}", ctx.profileHandler).Methods(http.MethodGet)
+	router.HandleFunc("/textures/{username}", s.texturesHandler).Methods(http.MethodGet)
+	router.HandleFunc("/textures/signed/{username}", s.signedTexturesHandler).Methods(http.MethodGet)
+	router.HandleFunc("/profile/{username}", s.profileHandler).Methods(http.MethodGet)
 	// Legacy
-	router.HandleFunc("/skins", ctx.skinGetHandler).Methods(http.MethodGet)
-	router.HandleFunc("/cloaks", ctx.capeGetHandler).Methods(http.MethodGet)
+	router.HandleFunc("/skins", s.skinGetHandler).Methods(http.MethodGet)
+	router.HandleFunc("/cloaks", s.capeGetHandler).Methods(http.MethodGet)
 	// Utils
-	router.HandleFunc("/signature-verification-key.der", ctx.signatureVerificationKeyHandler).Methods(http.MethodGet)
-	router.HandleFunc("/signature-verification-key.pem", ctx.signatureVerificationKeyHandler).Methods(http.MethodGet)
+	router.HandleFunc("/signature-verification-key.{format:(?:pem|der)}", s.signatureVerificationKeyHandler).Methods(http.MethodGet)
 
 	return router
 }
 
-func (ctx *Skinsystem) skinHandler(response http.ResponseWriter, request *http.Request) {
-	profile, err := ctx.ProfilesProvider.FindProfileByUsername(request.Context(), parseUsername(mux.Vars(request)["username"]), true)
+func (s *Skinsystem) skinHandler(response http.ResponseWriter, request *http.Request) {
+	profile, err := s.ProfilesProvider.FindProfileByUsername(request.Context(), parseUsername(mux.Vars(request)["username"]), true)
 	if err != nil {
 		apiServerError(response, fmt.Errorf("unable to retrieve a profile: %w", err))
 		return
@@ -71,7 +68,7 @@ func (ctx *Skinsystem) skinHandler(response http.ResponseWriter, request *http.R
 	http.Redirect(response, request, profile.SkinUrl, http.StatusMovedPermanently)
 }
 
-func (ctx *Skinsystem) skinGetHandler(response http.ResponseWriter, request *http.Request) {
+func (s *Skinsystem) skinGetHandler(response http.ResponseWriter, request *http.Request) {
 	username := request.URL.Query().Get("name")
 	if username == "" {
 		response.WriteHeader(http.StatusBadRequest)
@@ -80,11 +77,11 @@ func (ctx *Skinsystem) skinGetHandler(response http.ResponseWriter, request *htt
 
 	mux.Vars(request)["username"] = username
 
-	ctx.skinHandler(response, request)
+	s.skinHandler(response, request)
 }
 
-func (ctx *Skinsystem) capeHandler(response http.ResponseWriter, request *http.Request) {
-	profile, err := ctx.ProfilesProvider.FindProfileByUsername(request.Context(), parseUsername(mux.Vars(request)["username"]), true)
+func (s *Skinsystem) capeHandler(response http.ResponseWriter, request *http.Request) {
+	profile, err := s.ProfilesProvider.FindProfileByUsername(request.Context(), parseUsername(mux.Vars(request)["username"]), true)
 	if err != nil {
 		apiServerError(response, fmt.Errorf("unable to retrieve a profile: %w", err))
 		return
@@ -97,7 +94,7 @@ func (ctx *Skinsystem) capeHandler(response http.ResponseWriter, request *http.R
 	http.Redirect(response, request, profile.CapeUrl, http.StatusMovedPermanently)
 }
 
-func (ctx *Skinsystem) capeGetHandler(response http.ResponseWriter, request *http.Request) {
+func (s *Skinsystem) capeGetHandler(response http.ResponseWriter, request *http.Request) {
 	username := request.URL.Query().Get("name")
 	if username == "" {
 		response.WriteHeader(http.StatusBadRequest)
@@ -106,11 +103,11 @@ func (ctx *Skinsystem) capeGetHandler(response http.ResponseWriter, request *htt
 
 	mux.Vars(request)["username"] = username
 
-	ctx.capeHandler(response, request)
+	s.capeHandler(response, request)
 }
 
-func (ctx *Skinsystem) texturesHandler(response http.ResponseWriter, request *http.Request) {
-	profile, err := ctx.ProfilesProvider.FindProfileByUsername(request.Context(), mux.Vars(request)["username"], true)
+func (s *Skinsystem) texturesHandler(response http.ResponseWriter, request *http.Request) {
+	profile, err := s.ProfilesProvider.FindProfileByUsername(request.Context(), mux.Vars(request)["username"], true)
 	if err != nil {
 		apiServerError(response, fmt.Errorf("unable to retrieve a profile: %w", err))
 		return
@@ -133,8 +130,8 @@ func (ctx *Skinsystem) texturesHandler(response http.ResponseWriter, request *ht
 	_, _ = response.Write(responseData)
 }
 
-func (ctx *Skinsystem) signedTexturesHandler(response http.ResponseWriter, request *http.Request) {
-	profile, err := ctx.ProfilesProvider.FindProfileByUsername(
+func (s *Skinsystem) signedTexturesHandler(response http.ResponseWriter, request *http.Request) {
+	profile, err := s.ProfilesProvider.FindProfileByUsername(
 		request.Context(),
 		mux.Vars(request)["username"],
 		getToBool(request.URL.Query().Get("proxy")),
@@ -164,8 +161,8 @@ func (ctx *Skinsystem) signedTexturesHandler(response http.ResponseWriter, reque
 				Value:     profile.MojangTextures,
 			},
 			{
-				Name:  ctx.TexturesExtraParamName,
-				Value: ctx.TexturesExtraParamValue,
+				Name:  s.TexturesExtraParamName,
+				Value: s.TexturesExtraParamValue,
 			},
 		},
 	}
@@ -175,8 +172,8 @@ func (ctx *Skinsystem) signedTexturesHandler(response http.ResponseWriter, reque
 	_, _ = response.Write(responseJson)
 }
 
-func (ctx *Skinsystem) profileHandler(response http.ResponseWriter, request *http.Request) {
-	profile, err := ctx.ProfilesProvider.FindProfileByUsername(request.Context(), mux.Vars(request)["username"], true)
+func (s *Skinsystem) profileHandler(response http.ResponseWriter, request *http.Request) {
+	profile, err := s.ProfilesProvider.FindProfileByUsername(request.Context(), mux.Vars(request)["username"], true)
 	if err != nil {
 		apiServerError(response, fmt.Errorf("unable to retrieve a profile: %w", err))
 		return
@@ -203,7 +200,7 @@ func (ctx *Skinsystem) profileHandler(response http.ResponseWriter, request *htt
 	}
 
 	if request.URL.Query().Has("unsigned") && !getToBool(request.URL.Query().Get("unsigned")) {
-		signature, err := ctx.TexturesSigner.SignTextures(request.Context(), texturesProp.Value)
+		signature, err := s.SignerService.Sign(request.Context(), texturesProp.Value)
 		if err != nil {
 			apiServerError(response, fmt.Errorf("unable to sign textures: %w", err))
 			return
@@ -218,8 +215,8 @@ func (ctx *Skinsystem) profileHandler(response http.ResponseWriter, request *htt
 		Props: []*mojang.Property{
 			texturesProp,
 			{
-				Name:  ctx.TexturesExtraParamName,
-				Value: ctx.TexturesExtraParamValue,
+				Name:  s.TexturesExtraParamName,
+				Value: s.TexturesExtraParamValue,
 			},
 		},
 	}
@@ -229,32 +226,23 @@ func (ctx *Skinsystem) profileHandler(response http.ResponseWriter, request *htt
 	_, _ = response.Write(responseJson)
 }
 
-func (ctx *Skinsystem) signatureVerificationKeyHandler(response http.ResponseWriter, request *http.Request) {
-	publicKey, err := ctx.TexturesSigner.GetPublicKey(request.Context())
+func (s *Skinsystem) signatureVerificationKeyHandler(response http.ResponseWriter, request *http.Request) {
+	format := mux.Vars(request)["format"]
+	publicKey, err := s.SignerService.GetPublicKey(request.Context(), format)
 	if err != nil {
-		panic(err)
+		apiServerError(response, fmt.Errorf("unable to retrieve public key: %w", err))
+		return
 	}
 
-	asn1Bytes, err := x509.MarshalPKIXPublicKey(publicKey)
-	if err != nil {
-		panic(err)
-	}
-
-	if strings.HasSuffix(request.URL.Path, ".pem") {
-		publicKeyBlock := pem.Block{
-			Type:  "PUBLIC KEY",
-			Bytes: asn1Bytes,
-		}
-
-		publicKeyPemBytes := pem.EncodeToMemory(&publicKeyBlock)
-
-		response.Header().Set("Content-Disposition", "attachment; filename=\"yggdrasil_session_pubkey.pem\"")
-		_, _ = response.Write(publicKeyPemBytes)
+	if format == "pem" {
+		response.Header().Set("Content-Type", "application/x-pem-file")
+		response.Header().Set("Content-Disposition", `attachment; filename="yggdrasil_session_pubkey.pem"`)
 	} else {
 		response.Header().Set("Content-Type", "application/octet-stream")
-		response.Header().Set("Content-Disposition", "attachment; filename=\"yggdrasil_session_pubkey.der\"")
-		_, _ = response.Write(asn1Bytes)
+		response.Header().Set("Content-Disposition", `attachment; filename="yggdrasil_session_pubkey.der"`)
 	}
+
+	_, _ = io.WriteString(response, publicKey)
 }
 
 func parseUsername(username string) string {

internal/http/skinsystem_test.go

@@ -2,14 +2,10 @@ package http
 
 import (
 	"context"
-	"crypto/rsa"
-	"crypto/x509"
-	"encoding/pem"
 	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 	"time"
 
@@ -34,23 +30,18 @@ func (m *ProfilesProviderMock) FindProfileByUsername(ctx context.Context, userna
 	return result, args.Error(1)
 }
 
-type TexturesSignerMock struct {
+type SignerServiceMock struct {
 	mock.Mock
 }
 
-func (m *TexturesSignerMock) SignTextures(ctx context.Context, textures string) (string, error) {
-	args := m.Called(ctx, textures)
+func (m *SignerServiceMock) Sign(ctx context.Context, data string) (string, error) {
+	args := m.Called(ctx, data)
 	return args.String(0), args.Error(1)
 }
 
-func (m *TexturesSignerMock) GetPublicKey(ctx context.Context) (*rsa.PublicKey, error) {
-	args := m.Called(ctx)
-	var publicKey *rsa.PublicKey
-	if casted, ok := args.Get(0).(*rsa.PublicKey); ok {
-		publicKey = casted
-	}
-
-	return publicKey, args.Error(1)
+func (m *SignerServiceMock) GetPublicKey(ctx context.Context, format string) (string, error) {
+	args := m.Called(ctx, format)
+	return args.String(0), args.Error(1)
 }
 
 type SkinsystemTestSuite struct {
@@ -59,7 +50,7 @@ type SkinsystemTestSuite struct {
 	App *Skinsystem
 
 	ProfilesProvider *ProfilesProviderMock
-	TexturesSigner   *TexturesSignerMock
+	SignerService    *SignerServiceMock
 }
 
 /********************
@@ -73,11 +64,11 @@ func (t *SkinsystemTestSuite) SetupSubTest() {
 	}
 
 	t.ProfilesProvider = &ProfilesProviderMock{}
-	t.TexturesSigner = &TexturesSignerMock{}
+	t.SignerService = &SignerServiceMock{}
 
 	t.App = &Skinsystem{
 		ProfilesProvider:        t.ProfilesProvider,
-		TexturesSigner:          t.TexturesSigner,
+		SignerService:           t.SignerService,
 		TexturesExtraParamName:  "texturesParamName",
 		TexturesExtraParamValue: "texturesParamValue",
 	}
@@ -85,7 +76,7 @@ func (t *SkinsystemTestSuite) SetupSubTest() {
 
 func (t *SkinsystemTestSuite) TearDownSubTest() {
 	t.ProfilesProvider.AssertExpectations(t.T())
-	t.TexturesSigner.AssertExpectations(t.T())
+	t.SignerService.AssertExpectations(t.T())
 }
 
 func (t *SkinsystemTestSuite) TestSkinHandler() {
@@ -470,7 +461,7 @@ func (t *SkinsystemTestSuite) TestProfile() {
 			SkinUrl:   "https://example.com/skin.png",
 			SkinModel: "slim",
 		}, nil)
-		t.TexturesSigner.On("SignTextures", mock.Anything, "eyJ0aW1lc3RhbXAiOjE2MTQyMTQyMjMwMDAsInByb2ZpbGVJZCI6Im1vY2stdXVpZCIsInByb2ZpbGVOYW1lIjoibW9ja191c2VybmFtZSIsInRleHR1cmVzIjp7IlNLSU4iOnsidXJsIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9za2luLnBuZyIsIm1ldGFkYXRhIjp7Im1vZGVsIjoic2xpbSJ9fX19").Return("mock signature", nil)
+		t.SignerService.On("Sign", mock.Anything, "eyJ0aW1lc3RhbXAiOjE2MTQyMTQyMjMwMDAsInByb2ZpbGVJZCI6Im1vY2stdXVpZCIsInByb2ZpbGVOYW1lIjoibW9ja191c2VybmFtZSIsInRleHR1cmVzIjp7IlNLSU4iOnsidXJsIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9za2luLnBuZyIsIm1ldGFkYXRhIjp7Im1vZGVsIjoic2xpbSJ9fX19").Return("mock signature", nil)
 
 		t.App.Handler().ServeHTTP(w, req)
 
@@ -526,7 +517,7 @@ func (t *SkinsystemTestSuite) TestProfile() {
 		w := httptest.NewRecorder()
 
 		t.ProfilesProvider.On("FindProfileByUsername", mock.Anything, "mock_username", true).Return(&db.Profile{}, nil)
-		t.TexturesSigner.On("SignTextures", mock.Anything, mock.Anything).Return("", errors.New("mock error"))
+		t.SignerService.On("Sign", mock.Anything, mock.Anything).Return("", errors.New("mock error"))
 
 		t.App.Handler().ServeHTTP(w, req)
 
@@ -535,77 +526,52 @@ func (t *SkinsystemTestSuite) TestProfile() {
 	})
 }
 
-type signingKeyTestCase struct {
-	Name       string
-	KeyFormat  string
-	BeforeTest func(suite *SkinsystemTestSuite)
-	PanicErr   string
-	AfterTest  func(suite *SkinsystemTestSuite, response *http.Response)
-}
-
-var signingKeyTestsCases = []*signingKeyTestCase{
-	{
-		Name:      "Get public key in DER format",
-		KeyFormat: "DER",
-		BeforeTest: func(suite *SkinsystemTestSuite) {
-			pubPem, _ := pem.Decode([]byte("-----BEGIN PUBLIC KEY-----\nMFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANbUpVCZkMKpfvYZ08W3lumdAaYxLBnm\nUDlzHBQH3DpYef5WCO32TDU6feIJ58A0lAywgtZ4wwi2dGHOz/1hAvcCAwEAAQ==\n-----END PUBLIC KEY-----"))
-			publicKey, _ := x509.ParsePKIXPublicKey(pubPem.Bytes)
-
-			suite.TexturesSigner.On("GetPublicKey", mock.Anything).Return(publicKey, nil)
-		},
-		AfterTest: func(suite *SkinsystemTestSuite, response *http.Response) {
-			suite.Equal(200, response.StatusCode)
-			suite.Equal("application/octet-stream", response.Header.Get("Content-Type"))
-			suite.Equal("attachment; filename=\"yggdrasil_session_pubkey.der\"", response.Header.Get("Content-Disposition"))
-			body, _ := io.ReadAll(response.Body)
-			suite.Equal([]byte{48, 92, 48, 13, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 1, 5, 0, 3, 75, 0, 48, 72, 2, 65, 0, 214, 212, 165, 80, 153, 144, 194, 169, 126, 246, 25, 211, 197, 183, 150, 233, 157, 1, 166, 49, 44, 25, 230, 80, 57, 115, 28, 20, 7, 220, 58, 88, 121, 254, 86, 8, 237, 246, 76, 53, 58, 125, 226, 9, 231, 192, 52, 148, 12, 176, 130, 214, 120, 195, 8, 182, 116, 97, 206, 207, 253, 97, 2, 247, 2, 3, 1, 0, 1}, body)
-		},
-	},
-	{
-		Name:      "Get public key in PEM format",
-		KeyFormat: "PEM",
-		BeforeTest: func(suite *SkinsystemTestSuite) {
-			pubPem, _ := pem.Decode([]byte("-----BEGIN PUBLIC KEY-----\nMFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANbUpVCZkMKpfvYZ08W3lumdAaYxLBnm\nUDlzHBQH3DpYef5WCO32TDU6feIJ58A0lAywgtZ4wwi2dGHOz/1hAvcCAwEAAQ==\n-----END PUBLIC KEY-----"))
-			publicKey, _ := x509.ParsePKIXPublicKey(pubPem.Bytes)
-
-			suite.TexturesSigner.On("GetPublicKey", mock.Anything).Return(publicKey, nil)
-		},
-		AfterTest: func(suite *SkinsystemTestSuite, response *http.Response) {
-			suite.Equal(200, response.StatusCode)
-			suite.Equal("text/plain; charset=utf-8", response.Header.Get("Content-Type"))
-			suite.Equal("attachment; filename=\"yggdrasil_session_pubkey.pem\"", response.Header.Get("Content-Disposition"))
-			body, _ := io.ReadAll(response.Body)
-			suite.Equal("-----BEGIN PUBLIC KEY-----\nMFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBANbUpVCZkMKpfvYZ08W3lumdAaYxLBnm\nUDlzHBQH3DpYef5WCO32TDU6feIJ58A0lAywgtZ4wwi2dGHOz/1hAvcCAwEAAQ==\n-----END PUBLIC KEY-----\n", string(body))
-		},
-	},
-	{
-		Name:      "Error while obtaining public key",
-		KeyFormat: "DER",
-		BeforeTest: func(suite *SkinsystemTestSuite) {
-			suite.TexturesSigner.On("GetPublicKey", mock.Anything).Return(nil, errors.New("textures signer error"))
-		},
-		PanicErr: "textures signer error",
-	},
-}
-
 func (t *SkinsystemTestSuite) TestSignatureVerificationKey() {
-	for _, testCase := range signingKeyTestsCases {
-		t.Run(testCase.Name, func() {
-			testCase.BeforeTest(t)
+	t.Run("in pem format", func() {
+		publicKey := "mock public key in pem format"
+		t.SignerService.On("GetPublicKey", mock.Anything, "pem").Return(publicKey, nil)
 
-			req := httptest.NewRequest("GET", "http://chrly/signature-verification-key."+strings.ToLower(testCase.KeyFormat), nil)
-			w := httptest.NewRecorder()
+		req := httptest.NewRequest("GET", "http://chrly/signature-verification-key.pem", nil)
+		w := httptest.NewRecorder()
 
-			if testCase.PanicErr != "" {
-				t.PanicsWithError(testCase.PanicErr, func() {
-					t.App.Handler().ServeHTTP(w, req)
-				})
-			} else {
-				t.App.Handler().ServeHTTP(w, req)
-				testCase.AfterTest(t, w.Result())
-			}
-		})
-	}
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusOK, result.StatusCode)
+		t.Equal("application/x-pem-file", result.Header.Get("Content-Type"))
+		t.Equal(`attachment; filename="yggdrasil_session_pubkey.pem"`, result.Header.Get("Content-Disposition"))
+		body, _ := io.ReadAll(result.Body)
+		t.Equal(publicKey, string(body))
+	})
+
+	t.Run("in der format", func() {
+		publicKey := "mock public key in der format"
+		t.SignerService.On("GetPublicKey", mock.Anything, "der").Return(publicKey, nil)
+
+		req := httptest.NewRequest("GET", "http://chrly/signature-verification-key.der", nil)
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusOK, result.StatusCode)
+		t.Equal("application/octet-stream", result.Header.Get("Content-Type"))
+		t.Equal(`attachment; filename="yggdrasil_session_pubkey.der"`, result.Header.Get("Content-Disposition"))
+		body, _ := io.ReadAll(result.Body)
+		t.Equal(publicKey, string(body))
+	})
+
+	t.Run("handle error", func() {
+		t.SignerService.On("GetPublicKey", mock.Anything, "pem").Return("", errors.New("mock error"))
+
+		req := httptest.NewRequest("GET", "http://chrly/signature-verification-key.pem", nil)
+		w := httptest.NewRecorder()
+
+		t.App.Handler().ServeHTTP(w, req)
+
+		result := w.Result()
+		t.Equal(http.StatusInternalServerError, result.StatusCode)
+	})
 }
 
 func TestSkinsystem(t *testing.T) {

internal/security/jwt.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"slices"
 	"strings"
 	"time"
 
@@ -15,14 +16,23 @@ import (
 var now = time.Now
 var signingMethod = jwt.SigningMethodHS256
 
-const scopesClaim = "scopes"
-
 type Scope string
 
 const (
-	ProfileScope Scope = "profiles"
+	ProfilesScope Scope = "profiles"
+	SignScope     Scope = "sign"
 )
 
+var validScopes = []Scope{
+	ProfilesScope,
+	SignScope,
+}
+
+type claims struct {
+	jwt.RegisteredClaims
+	Scopes []Scope `json:"scopes"`
+}
+
 func NewJwt(key []byte) *Jwt {
 	return &Jwt{
 		Key: key,
@@ -38,11 +48,20 @@ func (t *Jwt) NewToken(scopes ...Scope) (string, error) {
 		return "", errors.New("you must specify at least one scope")
 	}
 
-	token := jwt.NewWithClaims(signingMethod, jwt.MapClaims{
-		"iss":       "chrly",
-		"iat":       now().Unix(),
-		scopesClaim: scopes,
-	})
+	for _, scope := range scopes {
+		if !slices.Contains(validScopes, scope) {
+			return "", fmt.Errorf("unknown scope %s", scope)
+		}
+	}
+
+	token := jwt.New(signingMethod)
+	token.Claims = &claims{
+		jwt.RegisteredClaims{
+			Issuer:   "chrly",
+			IssuedAt: jwt.NewNumericDate(now()),
+		},
+		scopes,
+	}
 	token.Header["v"] = version.MajorVersion
 
 	return token.SignedString(t.Key)
@@ -52,7 +71,7 @@ func (t *Jwt) NewToken(scopes ...Scope) (string, error) {
 var MissingAuthenticationError = errors.New("authentication value not provided")
 var InvalidTokenError = errors.New("passed authentication value is invalid")
 
-func (t *Jwt) Authenticate(req *http.Request) error {
+func (t *Jwt) Authenticate(req *http.Request, scope Scope) error {
 	bearerToken := req.Header.Get("Authorization")
 	if bearerToken == "" {
 		return MissingAuthenticationError
@@ -62,8 +81,8 @@ func (t *Jwt) Authenticate(req *http.Request) error {
 		return InvalidTokenError
 	}
 
-	tokenStr := bearerToken[7:]
-	token, err := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
+	tokenStr := bearerToken[7:] // trim "bearer " part
+	token, err := jwt.ParseWithClaims(tokenStr, &claims{}, func(token *jwt.Token) (interface{}, error) {
 		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
 			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
 		}
@@ -78,5 +97,10 @@ func (t *Jwt) Authenticate(req *http.Request) error {
 		return errors.Join(InvalidTokenError, errors.New("missing v header"))
 	}
 
+	claims := token.Claims.(*claims)
+	if !slices.Contains(claims.Scopes, scope) {
+		return errors.New("the token doesn't have the scope to perform the action")
+	}
+
 	return nil
 }

internal/security/jwt_test.go

@@ -16,10 +16,16 @@ func TestJwtAuth_NewToken(t *testing.T) {
 		return time.Date(2024, 2, 1, 11, 26, 15, 0, time.UTC)
 	}
 
-	t.Run("with scope", func(t *testing.T) {
-		token, err := jwt.NewToken(ProfileScope, "custom-scope")
+	t.Run("with known scope", func(t *testing.T) {
+		token, err := jwt.NewToken(ProfilesScope, SignScope)
 		require.NoError(t, err)
-		require.Equal(t, "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCIsInYiOjV9.eyJpYXQiOjE3MDY3ODY3NzUsImlzcyI6ImNocmx5Iiwic2NvcGVzIjpbInByb2ZpbGVzIiwiY3VzdG9tLXNjb3BlIl19.Iq673YyWWkJZjIkBmKYRN8Lx9qoD39S_e-MegG0aORM", token)
+		require.Equal(t, "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCIsInYiOjV9.eyJpc3MiOiJjaHJseSIsImlhdCI6MTcwNjc4Njc3NSwic2NvcGVzIjpbInByb2ZpbGVzIiwic2lnbiJdfQ.HkNGiDba3I_bLGN6sF0eTE5n6rMLgYfAZZEqI4xb2X4", token)
+	})
+
+	t.Run("with unknown scope", func(t *testing.T) {
+		token, err := jwt.NewToken("scope-123")
+		require.ErrorContains(t, err, "unknown")
+		require.Empty(t, token)
 	})
 
 	t.Run("no scopes", func(t *testing.T) {
@@ -34,41 +40,48 @@ func TestJwtAuth_Authenticate(t *testing.T) {
 	t.Run("success", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
 		req.Header.Add("Authorization", "Bearer "+jwtString)
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.NoError(t, err)
 	})
 
+	t.Run("has no required scope", func(t *testing.T) {
+		req := httptest.NewRequest("POST", "http://localhost", nil)
+		req.Header.Add("Authorization", "Bearer "+jwtString)
+		err := jwt.Authenticate(req, SignScope)
+		require.ErrorContains(t, err, "scope")
+	})
+
 	t.Run("request without auth header", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.ErrorIs(t, err, MissingAuthenticationError)
 	})
 
 	t.Run("no bearer token prefix", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
 		req.Header.Add("Authorization", "trash")
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.ErrorIs(t, err, InvalidTokenError)
 	})
 
 	t.Run("bearer token but not jwt", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
 		req.Header.Add("Authorization", "Bearer seems.like.jwt")
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.ErrorIs(t, err, InvalidTokenError)
 	})
 
 	t.Run("invalid signature", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
 		req.Header.Add("Authorization", "Bearer "+jwtString+"123")
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.ErrorIs(t, err, InvalidTokenError)
 	})
 
 	t.Run("missing v header", func(t *testing.T) {
 		req := httptest.NewRequest("POST", "http://localhost", nil)
 		req.Header.Add("Authorization", "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE3MDY3ODY3NzUsImlzcyI6ImNocmx5Iiwic2NvcGVzIjpbInByb2ZpbGVzIl19.zOX2ZKyU37kjwt1p9uCHxALxWQD2UC0wWcAcNvBXGq0")
-		err := jwt.Authenticate(req)
+		err := jwt.Authenticate(req, ProfilesScope)
 		require.ErrorIs(t, err, InvalidTokenError)
 		require.ErrorContains(t, err, "missing v header")
 	})

internal/security/signer.go

@@ -1,15 +1,18 @@
 package security
 
 import (
-	"context"
 	"crypto"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha1"
-	"encoding/base64"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"io"
 )
 
 var randomReader = rand.Reader
+var invalidKeyFormat = errors.New(`invalid key format: it should be"der" or "pem"`)
 
 func NewSigner(key *rsa.PrivateKey) *Signer {
 	return &Signer{Key: key}
@@ -19,23 +22,38 @@ type Signer struct {
 	Key *rsa.PrivateKey
 }
 
-func (s *Signer) SignTextures(ctx context.Context, textures string) (string, error) {
-	message := []byte(textures)
+func (s *Signer) Sign(data io.Reader) ([]byte, error) {
 	messageHash := sha1.New()
-	_, err := messageHash.Write(message)
+	_, err := io.Copy(messageHash, data)
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 
 	messageHashSum := messageHash.Sum(nil)
 	signature, err := rsa.SignPKCS1v15(randomReader, s.Key, crypto.SHA1, messageHashSum)
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 
-	return base64.StdEncoding.EncodeToString(signature), nil
+	return signature, nil
 }
 
-func (s *Signer) GetPublicKey(ctx context.Context) (*rsa.PublicKey, error) {
-	return &s.Key.PublicKey, nil
+func (s *Signer) GetPublicKey(format string) ([]byte, error) {
+	if format != "der" && format != "pem" {
+		return nil, invalidKeyFormat
+	}
+
+	asn1Bytes, err := x509.MarshalPKIXPublicKey(s.Key.Public())
+	if err != nil {
+		return nil, err
+	}
+
+	if format == "pem" {
+		return pem.EncodeToMemory(&pem.Block{
+			Type:  "PUBLIC KEY",
+			Bytes: asn1Bytes,
+		}), nil
+	}
+
+	return asn1Bytes, nil
 }

internal/security/signer_test.go

@@ -1,10 +1,9 @@
 package security
 
 import (
-	"context"
-	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -17,7 +16,7 @@ func (c *ConstantReader) Read(p []byte) (int, error) {
 	return 1, nil
 }
 
-func TestSigner_SignTextures(t *testing.T) {
+func TestSigner_Sign(t *testing.T) {
 	randomReader = &ConstantReader{}
 
 	rawKey, _ := pem.Decode([]byte("-----BEGIN RSA PRIVATE KEY-----\nMIIBOwIBAAJBANbUpVCZkMKpfvYZ08W3lumdAaYxLBnmUDlzHBQH3DpYef5WCO32\nTDU6feIJ58A0lAywgtZ4wwi2dGHOz/1hAvcCAwEAAQJAItaxSHTe6PKbyEU/9pxj\nONdhYRYwVLLo56gnMYhkyoEqaaMsfov8hhoepkYZBMvZFB2bDOsQ2SaJ+E2eiBO4\nAQIhAPssS0+BR9w0bOdmjGqmdE9NrN5UJQcOW13s29+6QzUBAiEA2vWOepA5Apiu\npEA3pwoGdkVCrNSnnKjDQzDXBnpd3/cCIEFNd9sY4qUG4FWdXN6RnmXL7Sj0uZfH\nDMwzu8rEM5sBAiEAhvdoDNqLmbMdq3c+FsPSOeL1d21Zp/JK8kbPtFmHNf8CIQDV\n6FSZDwvWfuxaM7BsycQONkjDBTPNu+lqctJBGnBv3A==\n-----END RSA PRIVATE KEY-----\n"))
@@ -25,9 +24,14 @@ func TestSigner_SignTextures(t *testing.T) {
 
 	signer := NewSigner(key)
 
-	signature, err := signer.SignTextures(context.Background(), "eyJ0aW1lc3RhbXAiOjE2MTQzMDcxMzQsInByb2ZpbGVJZCI6ImZmYzhmZGM5NTgyNDUwOWU4YTU3Yzk5Yjk0MGZiOTk2IiwicHJvZmlsZU5hbWUiOiJFcmlja1NrcmF1Y2giLCJ0ZXh0dXJlcyI6eyJTS0lOIjp7InVybCI6Imh0dHA6Ly9lbHkuYnkvc3RvcmFnZS9za2lucy82OWM2NzQwZDI5OTNlNWQ2ZjZhN2ZjOTI0MjBlZmMyOS5wbmcifX0sImVseSI6dHJ1ZX0")
+	signature, err := signer.Sign(strings.NewReader("mock string to sign"))
 	require.NoError(t, err)
-	require.Equal(t, "IyHCxTP5ITquEXTHcwCtLd08jWWy16JwlQeWg8naxhoAVQecHGRdzHRscuxtdq/446kmeox7h4EfRN2A2ZLL+A==", signature)
+	require.Equal(t, []byte{
+		0xd0, 0x88, 0xc6, 0x65, 0x27, 0x5d, 0xe4, 0x86, 0x6b, 0x7a, 0x5a, 0xd, 0x94, 0x6f, 0x80, 0x88, 0x12, 0x8e, 0x65,
+		0x75, 0xfb, 0xba, 0xcb, 0x7f, 0x90, 0xf5, 0xae, 0x5d, 0x2c, 0x5d, 0x60, 0xf6, 0x83, 0x54, 0xd3, 0x40, 0xd, 0x1f,
+		0xc0, 0xbc, 0x6d, 0xa8, 0x6f, 0x6, 0xd8, 0x38, 0x74, 0x5b, 0x4f, 0x15, 0x82, 0x6d, 0x67, 0x95, 0x7b, 0xf, 0xcc,
+		0xf3, 0x51, 0xfe, 0xcd, 0xb9, 0x1e, 0xdf,
+	}, signature)
 }
 
 func TestSigner_GetPublicKey(t *testing.T) {
@@ -38,7 +42,40 @@ func TestSigner_GetPublicKey(t *testing.T) {
 
 	signer := NewSigner(key)
 
-	publicKey, err := signer.GetPublicKey(context.Background())
-	require.NoError(t, err)
-	require.IsType(t, &rsa.PublicKey{}, publicKey)
+	t.Run("pem format", func(t *testing.T) {
+		publicKey, err := signer.GetPublicKey("pem")
+		require.NoError(t, err)
+		require.Equal(t, []byte{
+			0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0x42, 0x45, 0x47, 0x49, 0x4e, 0x20, 0x50, 0x55, 0x42, 0x4c, 0x49, 0x43, 0x20,
+			0x4b, 0x45, 0x59, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d, 0xa, 0x4d, 0x46, 0x77, 0x77, 0x44, 0x51, 0x59, 0x4a, 0x4b,
+			0x6f, 0x5a, 0x49, 0x68, 0x76, 0x63, 0x4e, 0x41, 0x51, 0x45, 0x42, 0x42, 0x51, 0x41, 0x44, 0x53, 0x77, 0x41,
+			0x77, 0x53, 0x41, 0x4a, 0x42, 0x41, 0x4e, 0x62, 0x55, 0x70, 0x56, 0x43, 0x5a, 0x6b, 0x4d, 0x4b, 0x70, 0x66,
+			0x76, 0x59, 0x5a, 0x30, 0x38, 0x57, 0x33, 0x6c, 0x75, 0x6d, 0x64, 0x41, 0x61, 0x59, 0x78, 0x4c, 0x42, 0x6e,
+			0x6d, 0xa, 0x55, 0x44, 0x6c, 0x7a, 0x48, 0x42, 0x51, 0x48, 0x33, 0x44, 0x70, 0x59, 0x65, 0x66, 0x35, 0x57,
+			0x43, 0x4f, 0x33, 0x32, 0x54, 0x44, 0x55, 0x36, 0x66, 0x65, 0x49, 0x4a, 0x35, 0x38, 0x41, 0x30, 0x6c, 0x41,
+			0x79, 0x77, 0x67, 0x74, 0x5a, 0x34, 0x77, 0x77, 0x69, 0x32, 0x64, 0x47, 0x48, 0x4f, 0x7a, 0x2f, 0x31, 0x68,
+			0x41, 0x76, 0x63, 0x43, 0x41, 0x77, 0x45, 0x41, 0x41, 0x51, 0x3d, 0x3d, 0xa, 0x2d, 0x2d, 0x2d, 0x2d, 0x2d,
+			0x45, 0x4e, 0x44, 0x20, 0x50, 0x55, 0x42, 0x4c, 0x49, 0x43, 0x20, 0x4b, 0x45, 0x59, 0x2d, 0x2d, 0x2d, 0x2d,
+			0x2d, 0xa,
+		}, publicKey)
+	})
+
+	t.Run("der format", func(t *testing.T) {
+		publicKey, err := signer.GetPublicKey("der")
+		require.NoError(t, err)
+		require.Equal(t, []byte{
+			0x30, 0x5c, 0x30, 0xd, 0x6, 0x9, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0xd, 0x1, 0x1, 0x1, 0x5, 0x0, 0x3, 0x4b, 0x0,
+			0x30, 0x48, 0x2, 0x41, 0x0, 0xd6, 0xd4, 0xa5, 0x50, 0x99, 0x90, 0xc2, 0xa9, 0x7e, 0xf6, 0x19, 0xd3, 0xc5,
+			0xb7, 0x96, 0xe9, 0x9d, 0x1, 0xa6, 0x31, 0x2c, 0x19, 0xe6, 0x50, 0x39, 0x73, 0x1c, 0x14, 0x7, 0xdc, 0x3a,
+			0x58, 0x79, 0xfe, 0x56, 0x8, 0xed, 0xf6, 0x4c, 0x35, 0x3a, 0x7d, 0xe2, 0x9, 0xe7, 0xc0, 0x34, 0x94, 0xc,
+			0xb0, 0x82, 0xd6, 0x78, 0xc3, 0x8, 0xb6, 0x74, 0x61, 0xce, 0xcf, 0xfd, 0x61, 0x2, 0xf7, 0x2, 0x3, 0x1, 0x0,
+			0x1,
+		}, publicKey)
+	})
+
+	t.Run("unknown format", func(t *testing.T) {
+		publicKey, err := signer.GetPublicKey("unknown")
+		require.Nil(t, publicKey)
+		require.ErrorContains(t, err, "invalid")
+	})
 }