diff --git a/example/internal/mock/storage.go b/example/internal/mock/storage.go
index b8a1648..214ba54 100644
--- a/example/internal/mock/storage.go
+++ b/example/internal/mock/storage.go
@@ -95,7 +95,7 @@ func (a *AuthRequest) GetScopes() []string {
 	}
 }
 
-func (a *AuthRequest) SetCurrentScopes(scopes oidc.Scopes) {}
+func (a *AuthRequest) SetCurrentScopes(scopes []string) {}
 
 func (a *AuthRequest) GetState() string {
 	return ""
@@ -243,7 +243,7 @@ func (s *AuthStorage) SetIntrospectionFromToken(ctx context.Context, introspect
 	return nil
 }
 
-func (s *AuthStorage) ValidateJWTProfileScopes(ctx context.Context, userID string, scope oidc.Scopes) (oidc.Scopes, error) {
+func (s *AuthStorage) ValidateJWTProfileScopes(ctx context.Context, userID string, scope []string) ([]string, error) {
 	return scope, nil
 }
 
diff --git a/pkg/client/client.go b/pkg/client/client.go
index b2b815e..708b79c 100644
--- a/pkg/client/client.go
+++ b/pkg/client/client.go
@@ -17,8 +17,8 @@ import (
 var (
 	Encoder = func() utils.Encoder {
 		e := schema.NewEncoder()
-		e.RegisterEncoder(oidc.Scopes{}, func(value reflect.Value) string {
-			return value.Interface().(oidc.Scopes).Encode()
+		e.RegisterEncoder(oidc.SpaceDelimitedArray{}, func(value reflect.Value) string {
+			return value.Interface().(oidc.SpaceDelimitedArray).Encode()
 		})
 		return e
 	}()
diff --git a/pkg/client/rp/relaying_party.go b/pkg/client/rp/relaying_party.go
index 5a48951..94593ff 100644
--- a/pkg/client/rp/relaying_party.go
+++ b/pkg/client/rp/relaying_party.go
@@ -430,10 +430,10 @@ func WithCodeChallenge(codeChallenge string) AuthURLOpt {
 }
 
 //WithPrompt sets the `prompt` params in the auth request
-func WithPrompt(prompt oidc.Prompt) AuthURLOpt {
+func WithPrompt(prompt ...string) AuthURLOpt {
 	return func() []oauth2.AuthCodeOption {
 		return []oauth2.AuthCodeOption{
-			oauth2.SetAuthURLParam("prompt", string(prompt)),
+			oauth2.SetAuthURLParam("prompt", oidc.SpaceDelimitedArray(prompt).Encode()),
 		}
 	}
 }
diff --git a/pkg/oidc/authorization.go b/pkg/oidc/authorization.go
index 71776af..79d0c1e 100644
--- a/pkg/oidc/authorization.go
+++ b/pkg/oidc/authorization.go
@@ -44,39 +44,39 @@ const (
 
 	//PromptNone (`none`) disallows the Authorization Server to display any authentication or consent user interface pages.
 	//An error (login_required, interaction_required, ...) will be returned if the user is not already authenticated or consent is needed
-	PromptNone Prompt = "none"
+	PromptNone = "none"
 
 	//PromptLogin (`login`) directs the Authorization Server to prompt the End-User for reauthentication.
-	PromptLogin Prompt = "login"
+	PromptLogin = "login"
 
 	//PromptConsent (`consent`) directs the Authorization Server to prompt the End-User for consent (of sharing information).
-	PromptConsent Prompt = "consent"
+	PromptConsent = "consent"
 
 	//PromptSelectAccount (`select_account `) directs the Authorization Server to prompt the End-User to select a user account (to enable multi user / session switching)
-	PromptSelectAccount Prompt = "select_account"
+	PromptSelectAccount = "select_account"
 )
 
 //AuthRequest according to:
 //https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
 type AuthRequest struct {
 	ID           string
-	Scopes       Scopes       `schema:"scope"`
-	ResponseType ResponseType `schema:"response_type"`
-	ClientID     string       `schema:"client_id"`
-	RedirectURI  string       `schema:"redirect_uri"` //TODO: type
+	Scopes       SpaceDelimitedArray `schema:"scope"`
+	ResponseType ResponseType        `schema:"response_type"`
+	ClientID     string              `schema:"client_id"`
+	RedirectURI  string              `schema:"redirect_uri"` //TODO: type
 
 	State string `schema:"state"`
 
 	// ResponseMode TODO: ?
 
-	Nonce       string   `schema:"nonce"`
-	Display     Display  `schema:"display"`
-	Prompt      Prompt   `schema:"prompt"`
-	MaxAge      uint32   `schema:"max_age"`
-	UILocales   Locales  `schema:"ui_locales"`
-	IDTokenHint string   `schema:"id_token_hint"`
-	LoginHint   string   `schema:"login_hint"`
-	ACRValues   []string `schema:"acr_values"`
+	Nonce       string              `schema:"nonce"`
+	Display     Display             `schema:"display"`
+	Prompt      SpaceDelimitedArray `schema:"prompt"`
+	MaxAge      *uint               `schema:"max_age"`
+	UILocales   Locales             `schema:"ui_locales"`
+	IDTokenHint string              `schema:"id_token_hint"`
+	LoginHint   string              `schema:"login_hint"`
+	ACRValues   []string            `schema:"acr_values"`
 
 	CodeChallenge       string              `schema:"code_challenge"`
 	CodeChallengeMethod CodeChallengeMethod `schema:"code_challenge_method"`
diff --git a/pkg/oidc/introspection.go b/pkg/oidc/introspection.go
index a2176aa..9b2bad7 100644
--- a/pkg/oidc/introspection.go
+++ b/pkg/oidc/introspection.go
@@ -21,7 +21,7 @@ type IntrospectionResponse interface {
 	UserInfoSetter
 	SetActive(bool)
 	IsActive() bool
-	SetScopes(scopes Scopes)
+	SetScopes(scopes []string)
 	SetClientID(id string)
 }
 
@@ -30,10 +30,10 @@ func NewIntrospectionResponse() IntrospectionResponse {
 }
 
 type introspectionResponse struct {
-	Active   bool   `json:"active"`
-	Scope    Scopes `json:"scope,omitempty"`
-	ClientID string `json:"client_id,omitempty"`
-	Subject  string `json:"sub,omitempty"`
+	Active   bool                `json:"active"`
+	Scope    SpaceDelimitedArray `json:"scope,omitempty"`
+	ClientID string              `json:"client_id,omitempty"`
+	Subject  string              `json:"sub,omitempty"`
 	userInfoProfile
 	userInfoEmail
 	userInfoPhone
@@ -46,7 +46,7 @@ func (u *introspectionResponse) IsActive() bool {
 	return u.Active
 }
 
-func (u *introspectionResponse) SetScopes(scope Scopes) {
+func (u *introspectionResponse) SetScopes(scope []string) {
 	u.Scope = scope
 }
 
diff --git a/pkg/oidc/jwt_profile.go b/pkg/oidc/jwt_profile.go
index 6969783..25b7caa 100644
--- a/pkg/oidc/jwt_profile.go
+++ b/pkg/oidc/jwt_profile.go
@@ -1,9 +1,9 @@
 package oidc
 
 type JWTProfileGrantRequest struct {
-	Assertion string    `schema:"assertion"`
-	Scope     Scopes    `schema:"scope"`
-	GrantType GrantType `schema:"grant_type"`
+	Assertion string              `schema:"assertion"`
+	Scope     SpaceDelimitedArray `schema:"scope"`
+	GrantType GrantType           `schema:"grant_type"`
 }
 
 //NewJWTProfileGrantRequest creates an oauth2 `JSON Web Token (JWT) Profile` Grant
diff --git a/pkg/oidc/token_request.go b/pkg/oidc/token_request.go
index 1136f8e..4899c3a 100644
--- a/pkg/oidc/token_request.go
+++ b/pkg/oidc/token_request.go
@@ -58,12 +58,12 @@ func (a *AccessTokenRequest) SetClientSecret(clientSecret string) {
 }
 
 type RefreshTokenRequest struct {
-	RefreshToken        string `schema:"refresh_token"`
-	Scopes              Scopes `schema:"scope"`
-	ClientID            string `schema:"client_id"`
-	ClientSecret        string `schema:"client_secret"`
-	ClientAssertion     string `schema:"client_assertion"`
-	ClientAssertionType string `schema:"client_assertion_type"`
+	RefreshToken        string              `schema:"refresh_token"`
+	Scopes              SpaceDelimitedArray `schema:"scope"`
+	ClientID            string              `schema:"client_id"`
+	ClientSecret        string              `schema:"client_secret"`
+	ClientAssertion     string              `schema:"client_assertion"`
+	ClientAssertionType string              `schema:"client_assertion_type"`
 }
 
 func (a *RefreshTokenRequest) GrantType() GrantType {
@@ -81,12 +81,12 @@ func (a *RefreshTokenRequest) SetClientSecret(clientSecret string) {
 }
 
 type JWTTokenRequest struct {
-	Issuer    string   `json:"iss"`
-	Subject   string   `json:"sub"`
-	Scopes    Scopes   `json:"-"`
-	Audience  Audience `json:"aud"`
-	IssuedAt  Time     `json:"iat"`
-	ExpiresAt Time     `json:"exp"`
+	Issuer    string              `json:"iss"`
+	Subject   string              `json:"sub"`
+	Scopes    SpaceDelimitedArray `json:"-"`
+	Audience  Audience            `json:"aud"`
+	IssuedAt  Time                `json:"iat"`
+	ExpiresAt Time                `json:"exp"`
 }
 
 //GetIssuer implements the Claims interface
@@ -143,12 +143,12 @@ func (j *JWTTokenRequest) GetScopes() []string {
 }
 
 type TokenExchangeRequest struct {
-	subjectToken       string   `schema:"subject_token"`
-	subjectTokenType   string   `schema:"subject_token_type"`
-	actorToken         string   `schema:"actor_token"`
-	actorTokenType     string   `schema:"actor_token_type"`
-	resource           []string `schema:"resource"`
-	audience           Audience `schema:"audience"`
-	Scope              Scopes   `schema:"scope"`
-	requestedTokenType string   `schema:"requested_token_type"`
+	subjectToken       string              `schema:"subject_token"`
+	subjectTokenType   string              `schema:"subject_token_type"`
+	actorToken         string              `schema:"actor_token"`
+	actorTokenType     string              `schema:"actor_token_type"`
+	resource           []string            `schema:"resource"`
+	audience           Audience            `schema:"audience"`
+	Scope              SpaceDelimitedArray `schema:"scope"`
+	requestedTokenType string              `schema:"requested_token_type"`
 }
diff --git a/pkg/oidc/types.go b/pkg/oidc/types.go
index 5525923..e72d67c 100644
--- a/pkg/oidc/types.go
+++ b/pkg/oidc/types.go
@@ -54,30 +54,36 @@ func (l *Locales) UnmarshalText(text []byte) error {
 	return nil
 }
 
-type Prompt string
+type MaxAge *uint
+
+func NewMaxAge(i uint) MaxAge {
+	return &i
+}
+
+type SpaceDelimitedArray []string
+
+type Prompt SpaceDelimitedArray
 
 type ResponseType string
 
-type Scopes []string
-
-func (s Scopes) Encode() string {
+func (s SpaceDelimitedArray) Encode() string {
 	return strings.Join(s, " ")
 }
 
-func (s *Scopes) UnmarshalText(text []byte) error {
+func (s *SpaceDelimitedArray) UnmarshalText(text []byte) error {
 	*s = strings.Split(string(text), " ")
 	return nil
 }
 
-func (s *Scopes) MarshalText() ([]byte, error) {
+func (s SpaceDelimitedArray) MarshalText() ([]byte, error) {
 	return []byte(s.Encode()), nil
 }
 
-func (s *Scopes) MarshalJSON() ([]byte, error) {
-	return json.Marshal((*s).Encode())
+func (s SpaceDelimitedArray) MarshalJSON() ([]byte, error) {
+	return json.Marshal((s).Encode())
 }
 
-func (s *Scopes) UnmarshalJSON(data []byte) error {
+func (s *SpaceDelimitedArray) UnmarshalJSON(data []byte) error {
 	var str string
 	if err := json.Unmarshal(data, &str); err != nil {
 		return err
diff --git a/pkg/oidc/types_test.go b/pkg/oidc/types_test.go
index 8138b4b..c03a775 100644
--- a/pkg/oidc/types_test.go
+++ b/pkg/oidc/types_test.go
@@ -220,7 +220,7 @@ func TestScopes_UnmarshalText(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			var scopes Scopes
+			var scopes SpaceDelimitedArray
 			if err := scopes.UnmarshalText(tt.args.text); (err != nil) != tt.wantErr {
 				t.Errorf("UnmarshalText() error = %v, wantErr %v", err, tt.wantErr)
 			}
@@ -230,7 +230,7 @@ func TestScopes_UnmarshalText(t *testing.T) {
 }
 func TestScopes_MarshalText(t *testing.T) {
 	type args struct {
-		scopes Scopes
+		scopes SpaceDelimitedArray
 	}
 	type res struct {
 		scopes []byte
@@ -244,7 +244,7 @@ func TestScopes_MarshalText(t *testing.T) {
 		{
 			"unknown value",
 			args{
-				Scopes{"unknown"},
+				SpaceDelimitedArray{"unknown"},
 			},
 			res{
 				[]byte("unknown"),
@@ -254,7 +254,7 @@ func TestScopes_MarshalText(t *testing.T) {
 		{
 			"struct",
 			args{
-				Scopes{`{"unknown":"value"}`},
+				SpaceDelimitedArray{`{"unknown":"value"}`},
 			},
 			res{
 				[]byte(`{"unknown":"value"}`),
@@ -264,7 +264,7 @@ func TestScopes_MarshalText(t *testing.T) {
 		{
 			"openid",
 			args{
-				Scopes{"openid"},
+				SpaceDelimitedArray{"openid"},
 			},
 			res{
 				[]byte("openid"),
@@ -274,7 +274,7 @@ func TestScopes_MarshalText(t *testing.T) {
 		{
 			"multiple scopes",
 			args{
-				Scopes{"openid", "email", "custom:scope"},
+				SpaceDelimitedArray{"openid", "email", "custom:scope"},
 			},
 			res{
 				[]byte("openid email custom:scope"),
diff --git a/pkg/op/auth_request.go b/pkg/op/auth_request.go
index 9e0cd45..fce681f 100644
--- a/pkg/op/auth_request.go
+++ b/pkg/op/auth_request.go
@@ -106,7 +106,11 @@ func ParseAuthorizeRequest(r *http.Request, decoder utils.Decoder) (*oidc.AuthRe
 }
 
 //ValidateAuthRequest validates the authorize parameters and returns the userID of the id_token_hint if passed
-func ValidateAuthRequest(ctx context.Context, authReq *oidc.AuthRequest, storage Storage, verifier IDTokenHintVerifier) (string, error) {
+func ValidateAuthRequest(ctx context.Context, authReq *oidc.AuthRequest, storage Storage, verifier IDTokenHintVerifier) (sub string, err error) {
+	authReq.MaxAge, err = ValidateAuthReqPrompt(authReq.Prompt, authReq.MaxAge)
+	if err != nil {
+		return "", err
+	}
 	client, err := storage.GetClientByClientID(ctx, authReq.ClientID)
 	if err != nil {
 		return "", ErrServerError(err.Error())
@@ -124,6 +128,19 @@ func ValidateAuthRequest(ctx context.Context, authReq *oidc.AuthRequest, storage
 	return ValidateAuthReqIDTokenHint(ctx, authReq.IDTokenHint, verifier)
 }
 
+//ValidateAuthReqPrompt validates the passed prompt values and sets max_age to 0 if prompt login is present
+func ValidateAuthReqPrompt(prompts []string, maxAge *uint) (_ *uint, err error) {
+	for _, prompt := range prompts {
+		if prompt == oidc.PromptNone && len(prompts) > 1 {
+			return nil, ErrInvalidRequest("The prompt parameter `none` must only be used as a single value")
+		}
+		if prompt == oidc.PromptLogin {
+			maxAge = oidc.NewMaxAge(0)
+		}
+	}
+	return maxAge, nil
+}
+
 //ValidateAuthReqScopes validates the passed scopes
 func ValidateAuthReqScopes(client Client, scopes []string) ([]string, error) {
 	if len(scopes) == 0 {
diff --git a/pkg/op/auth_request_test.go b/pkg/op/auth_request_test.go
index 9bec1e7..40e1a8a 100644
--- a/pkg/op/auth_request_test.go
+++ b/pkg/op/auth_request_test.go
@@ -123,7 +123,7 @@ func TestParseAuthorizeRequest(t *testing.T) {
 				}(),
 			},
 			res{
-				&oidc.AuthRequest{Scopes: oidc.Scopes{"openid"}},
+				&oidc.AuthRequest{Scopes: oidc.SpaceDelimitedArray{"openid"}},
 				false,
 			},
 		},
diff --git a/pkg/op/mock/storage.mock.go b/pkg/op/mock/storage.mock.go
index be261bb..4b44f2b 100644
--- a/pkg/op/mock/storage.mock.go
+++ b/pkg/op/mock/storage.mock.go
@@ -316,10 +316,10 @@ func (mr *MockStorageMockRecorder) TokenRequestByRefreshToken(arg0, arg1 interfa
 }
 
 // ValidateJWTProfileScopes mocks base method.
-func (m *MockStorage) ValidateJWTProfileScopes(arg0 context.Context, arg1 string, arg2 oidc.Scopes) (oidc.Scopes, error) {
+func (m *MockStorage) ValidateJWTProfileScopes(arg0 context.Context, arg1 string, arg2 []string) ([]string, error) {
 	m.ctrl.T.Helper()
 	ret := m.ctrl.Call(m, "ValidateJWTProfileScopes", arg0, arg1, arg2)
-	ret0, _ := ret[0].(oidc.Scopes)
+	ret0, _ := ret[0].([]string)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
diff --git a/pkg/op/mock/storage.mock.impl.go b/pkg/op/mock/storage.mock.impl.go
index 7689bd3..4855cf5 100644
--- a/pkg/op/mock/storage.mock.impl.go
+++ b/pkg/op/mock/storage.mock.impl.go
@@ -140,10 +140,10 @@ func (c *ConfClient) GetID() string {
 }
 
 func (c *ConfClient) AccessTokenLifetime() time.Duration {
-	return time.Duration(5 * time.Minute)
+	return 5 * time.Minute
 }
 func (c *ConfClient) IDTokenLifetime() time.Duration {
-	return time.Duration(5 * time.Minute)
+	return 5 * time.Minute
 }
 func (c *ConfClient) AccessTokenType() op.AccessTokenType {
 	return c.accessTokenType
diff --git a/pkg/op/session.go b/pkg/op/session.go
index 19ebab4..4d75098 100644
--- a/pkg/op/session.go
+++ b/pkg/op/session.go
@@ -83,13 +83,3 @@ func ValidateEndSessionRequest(ctx context.Context, req *oidc.EndSessionRequest,
 	}
 	return nil, ErrInvalidRequest("post_logout_redirect_uri invalid")
 }
-
-func NeedsExistingSession(authRequest *oidc.AuthRequest) bool {
-	if authRequest == nil {
-		return true
-	}
-	if authRequest.Prompt == oidc.PromptNone {
-		return true
-	}
-	return false
-}
diff --git a/pkg/op/storage.go b/pkg/op/storage.go
index 0e0794e..ca9ae7c 100644
--- a/pkg/op/storage.go
+++ b/pkg/op/storage.go
@@ -34,7 +34,7 @@ type OPStorage interface {
 	SetIntrospectionFromToken(ctx context.Context, userinfo oidc.IntrospectionResponse, tokenID, subject, clientID string) error
 	GetPrivateClaimsFromScopes(ctx context.Context, userID, clientID string, scopes []string) (map[string]interface{}, error)
 	GetKeyByIDAndUserID(ctx context.Context, keyID, userID string) (*jose.JSONWebKey, error)
-	ValidateJWTProfileScopes(ctx context.Context, userID string, scope oidc.Scopes) (oidc.Scopes, error)
+	ValidateJWTProfileScopes(ctx context.Context, userID string, scopes []string) ([]string, error)
 }
 
 type Storage interface {
diff --git a/pkg/op/token_refresh.go b/pkg/op/token_refresh.go
index 8072f30..debcca1 100644
--- a/pkg/op/token_refresh.go
+++ b/pkg/op/token_refresh.go
@@ -17,7 +17,7 @@ type RefreshTokenRequest interface {
 	GetClientID() string
 	GetScopes() []string
 	GetSubject() string
-	SetCurrentScopes(scopes oidc.Scopes)
+	SetCurrentScopes(scopes []string)
 }
 
 //RefreshTokenExchange handles the OAuth 2.0 refresh_token grant, including
@@ -72,7 +72,7 @@ func ValidateRefreshTokenRequest(ctx context.Context, tokenReq *oidc.RefreshToke
 //ValidateRefreshTokenScopes validates that the requested scope is a subset of the original auth request scope
 //it will set the requested scopes as current scopes onto RefreshTokenRequest
 //if empty the original scopes will be used
-func ValidateRefreshTokenScopes(requestedScopes oidc.Scopes, authRequest RefreshTokenRequest) error {
+func ValidateRefreshTokenScopes(requestedScopes []string, authRequest RefreshTokenRequest) error {
 	if len(requestedScopes) == 0 {
 		return nil
 	}