feat: action v2 signing (#8779)

# Which Problems Are Solved

The action v2 messages were didn't contain anything providing security
for the sent content.

# How the Problems Are Solved

Each Target now has a SigningKey, which can also be newly generated
through the API and returned at creation and through the Get-Endpoints.
There is now a HTTP header "Zitadel-Signature", which is generated with
the SigningKey and Payload, and also contains a timestamp to check with
a tolerance if the message took to long to sent.

# Additional Changes

The functionality to create and check the signature is provided in the
pkg/actions package, and can be reused in the SDK.

# Additional Context

Closes #7924

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

cmd/defaults.yaml

@@ -633,6 +633,9 @@ EncryptionKeys:
   User:
     EncryptionKeyID: "userKey" # ZITADEL_ENCRYPTIONKEYS_USER_ENCRYPTIONKEYID
     DecryptionKeyIDs: # ZITADEL_ENCRYPTIONKEYS_USER_DECRYPTIONKEYIDS (comma separated list)
+  Target:
+    EncryptionKeyID: "targetKey" # ZITADEL_ENCRYPTIONKEYS_TARGET_ENCRYPTIONKEYID
+    DecryptionKeyIDs: # ZITADEL_ENCRYPTIONKEYS_TARGET_DECRYPTIONKEYIDS (comma separated list)
   CSRFCookieKeyID: "csrfCookieKey" # ZITADEL_ENCRYPTIONKEYS_CSRFCOOKIEKEYID
   UserAgentCookieKeyID: "userAgentCookieKey" # ZITADEL_ENCRYPTIONKEYS_USERAGENTCOOKIEKEYID
 
@@ -910,6 +913,12 @@ DefaultInstance:
       IncludeUpperLetters: true # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_INITIALIZEUSERCODE_INCLUDEUPPERLETTERS
       IncludeDigits: true # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_INITIALIZEUSERCODE_INCLUDEDIGITS
       IncludeSymbols: false # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_INITIALIZEUSERCODE_INCLUDESYMBOLS
+    SigningKey:
+      Length: 36 # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_SIGNINGKEY_LENGTH
+      IncludeLowerLetters: true # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_SIGNINGKEY_INCLUDELOWERLETTERS
+      IncludeUpperLetters: true # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_SIGNINGKEY_INCLUDEUPPERLETTERS
+      IncludeDigits: true # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_SIGNINGKEY_INCLUDEDIGITS
+      IncludeSymbols: false # ZITADEL_DEFAULTINSTANCE_SECRETGENERATORS_SIGNINGKEY_INCLUDESYMBOLS
   PasswordComplexityPolicy:
     MinLength: 8 # ZITADEL_DEFAULTINSTANCE_PASSWORDCOMPLEXITYPOLICY_MINLENGTH
     HasLowercase: true # ZITADEL_DEFAULTINSTANCE_PASSWORDCOMPLEXITYPOLICY_HASLOWERCASE

cmd/encryption/encryption_keys.go

@@ -17,6 +17,7 @@ var (
 		"smsKey",
 		"smtpKey",
 		"userKey",
+		"targetKey",
 		"csrfCookieKey",
 		"userAgentCookieKey",
 	}
@@ -31,6 +32,7 @@ type EncryptionKeyConfig struct {
 	SMS                  *crypto.KeyConfig
 	SMTP                 *crypto.KeyConfig
 	User                 *crypto.KeyConfig
+	Target               *crypto.KeyConfig
 	CSRFCookieKeyID      string
 	UserAgentCookieKeyID string
 }
@@ -44,6 +46,7 @@ type EncryptionKeys struct {
 	SMS                crypto.EncryptionAlgorithm
 	SMTP               crypto.EncryptionAlgorithm
 	User               crypto.EncryptionAlgorithm
+	Target             crypto.EncryptionAlgorithm
 	CSRFCookieKey      []byte
 	UserAgentCookieKey []byte
 	OIDCKey            []byte
@@ -91,6 +94,10 @@ func EnsureEncryptionKeys(ctx context.Context, keyConfig *EncryptionKeyConfig, k
 	if err != nil {
 		return nil, err
 	}
+	keys.Target, err = crypto.NewAESCrypto(keyConfig.Target, keyStorage)
+	if err != nil {
+		return nil, err
+	}
 	key, err = crypto.LoadKey(keyConfig.CSRFCookieKeyID, keyStorage)
 	if err != nil {
 		return nil, err

cmd/mirror/projections.go

@@ -145,6 +145,7 @@ func projections(
 		keys.OTP,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		config.InternalAuthZ.RolePermissionMappings,
 		sessionTokenVerifier,
 		func(q *query.Queries) domain.PermissionCheck {
@@ -183,6 +184,7 @@ func projections(
 		keys.DomainVerification,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		&http.Client{},
 		func(ctx context.Context, permission, orgID, resourceID string) (err error) {
 			return internal_authz.CheckPermission(ctx, authZRepo, config.InternalAuthZ.RolePermissionMappings, permission, orgID, resourceID)

cmd/setup/03.go

@@ -86,6 +86,7 @@ func (mig *FirstInstance) Execute(ctx context.Context, _ eventstore.Event) error
 		nil,
 		nil,
 		nil,
+		nil,
 		0,
 		0,
 		0,

cmd/setup/config_change.go

@@ -53,6 +53,7 @@ func (mig *externalConfigChange) Execute(ctx context.Context, _ eventstore.Event
 		nil,
 		nil,
 		nil,
+		nil,
 		0,
 		0,
 		0,

cmd/setup/setup.go

@@ -366,6 +366,7 @@ func initProjections(
 		keys.OTP,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		config.InternalAuthZ.RolePermissionMappings,
 		sessionTokenVerifier,
 		func(q *query.Queries) domain.PermissionCheck {
@@ -422,6 +423,7 @@ func initProjections(
 		keys.DomainVerification,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		&http.Client{},
 		permissionCheck,
 		sessionTokenVerifier,

cmd/start/start.go

@@ -196,6 +196,7 @@ func startZitadel(ctx context.Context, config *Config, masterKey string, server
 		keys.OTP,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		config.InternalAuthZ.RolePermissionMappings,
 		sessionTokenVerifier,
 		func(q *query.Queries) domain.PermissionCheck {
@@ -245,6 +246,7 @@ func startZitadel(ctx context.Context, config *Config, masterKey string, server
 		keys.DomainVerification,
 		keys.OIDC,
 		keys.SAML,
+		keys.Target,
 		&http.Client{},
 		permissionCheck,
 		sessionTokenVerifier,

docs/docs/apis/actions/v3/testing-locally.md

@@ -48,6 +48,20 @@ func main() {
 
 What happens here is only a target which prints out the received request, which could also be handled with a different logic.
 
+### Check Signature
+
+To additionally check the signature header you can add the following to the example:
+```go
+	// validate signature
+	if err := actions.ValidatePayload(sentBody, req.Header.Get(actions.SigningHeader), signingKey); err != nil {
+		// if the signed content is not equal the sent content return an error
+		http.Error(w, "error", http.StatusInternalServerError)
+		return
+	}
+```
+
+Where you can replace 'signingKey' with the key received in the next step 'Create target'.
+
 ## Create target
 
 As you see in the example above the target is created with HTTP and port '8090' and if we want to use it as webhook, the target can be created as follows:

docs/docs/apis/actions/v3/usage.md

@@ -64,6 +64,13 @@ There are different types of Targets:
 
 The API documentation to create a target can be found [here](/apis/resources/action_service_v3/zitadel-actions-create-target)
 
+### Content Signing
+
+To ensure the integrity of request content, each call includes a 'ZITADEL-Signature' in the headers. This header contains an HMAC value computed from the request content and a timestamp, which can be used to time out requests. The logic for this process is provided in 'pkg/actions/signing.go'. The goal is to verify that the HMAC value in the header matches the HMAC value computed by the Target, ensuring that the sent and received requests are identical.
+
+Each Target resource now contains also a Signing Key, which gets generated and returned when a Target is [created](/apis/resources/action_service_v3/zitadel-actions-create-target),
+and can also be newly generated when a Target is [patched](/apis/resources/action_service_v3/zitadel-actions-patch-target).
+
 ## Execution
 
 ZITADEL decides on specific conditions if one or more Targets have to be called.

docs/package.json

@@ -17,7 +17,7 @@
     "generate:grpc": "buf generate ../proto",
     "generate:apidocs": "docusaurus gen-api-docs all",
     "generate:configdocs": "cp -r ../cmd/defaults.yaml ./docs/self-hosting/manage/configure/ && cp -r ../cmd/setup/steps.yaml ./docs/self-hosting/manage/configure/",
-    "generate:re-gen": "yarn clean-all && yarn gen-all",
+    "generate:re-gen": "yarn generate:clean-all && yarn generate",
     "generate:clean-all": "docusaurus clean-api-docs all"
   },
   "dependencies": {

internal/api/grpc/resources/action/v3alpha/integration_test/query_test.go

@@ -62,6 +62,7 @@ func TestServer_GetTarget(t *testing.T) {
 					request.Id = resp.GetDetails().GetId()
 					response.Target.Config.Name = name
 					response.Target.Details = resp.GetDetails()
+					response.Target.SigningKey = resp.GetSigningKey()
 					return nil
 				},
 				req: &action.GetTargetRequest{},
@@ -92,6 +93,7 @@ func TestServer_GetTarget(t *testing.T) {
 					request.Id = resp.GetDetails().GetId()
 					response.Target.Config.Name = name
 					response.Target.Details = resp.GetDetails()
+					response.Target.SigningKey = resp.GetSigningKey()
 					return nil
 				},
 				req: &action.GetTargetRequest{},
@@ -122,6 +124,7 @@ func TestServer_GetTarget(t *testing.T) {
 					request.Id = resp.GetDetails().GetId()
 					response.Target.Config.Name = name
 					response.Target.Details = resp.GetDetails()
+					response.Target.SigningKey = resp.GetSigningKey()
 					return nil
 				},
 				req: &action.GetTargetRequest{},
@@ -154,6 +157,7 @@ func TestServer_GetTarget(t *testing.T) {
 					request.Id = resp.GetDetails().GetId()
 					response.Target.Config.Name = name
 					response.Target.Details = resp.GetDetails()
+					response.Target.SigningKey = resp.GetSigningKey()
 					return nil
 				},
 				req: &action.GetTargetRequest{},
@@ -186,6 +190,7 @@ func TestServer_GetTarget(t *testing.T) {
 					request.Id = resp.GetDetails().GetId()
 					response.Target.Config.Name = name
 					response.Target.Details = resp.GetDetails()
+					response.Target.SigningKey = resp.GetSigningKey()
 					return nil
 				},
 				req: &action.GetTargetRequest{},
@@ -230,6 +235,7 @@ func TestServer_GetTarget(t *testing.T) {
 				gotTarget := got.GetTarget()
 				integration.AssertResourceDetails(ttt, wantTarget.GetDetails(), gotTarget.GetDetails())
 				assert.EqualExportedValues(ttt, wantTarget.GetConfig(), gotTarget.GetConfig())
+				assert.Equal(ttt, wantTarget.GetSigningKey(), gotTarget.GetSigningKey())
 			}, retryDuration, tick, "timeout waiting for expected target result")
 		})
 	}
@@ -492,6 +498,7 @@ func TestServer_ListTargets(t *testing.T) {
 					for i := range tt.want.Result {
 						integration.AssertResourceDetails(ttt, tt.want.Result[i].GetDetails(), got.Result[i].GetDetails())
 						assert.EqualExportedValues(ttt, tt.want.Result[i].GetConfig(), got.Result[i].GetConfig())
+						assert.NotEmpty(ttt, got.Result[i].GetSigningKey())
 					}
 				}
 				integration.AssertResourceListDetails(ttt, tt.want, got)

internal/api/grpc/resources/action/v3alpha/integration_test/target_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/brianvoe/gofakeit/v6"
 	"github.com/muhlemmer/gu"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/types/known/durationpb"
 	"google.golang.org/protobuf/types/known/timestamppb"
@@ -200,11 +201,12 @@ func TestServer_CreateTarget(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			got, err := instance.Client.ActionV3Alpha.CreateTarget(tt.ctx, &action.CreateTargetRequest{Target: tt.req})
 			if tt.wantErr {
-				require.Error(t, err)
+				assert.Error(t, err)
-				return
+			} else {
-			}
+				assert.NoError(t, err)
-			require.NoError(t, err)
 				integration.AssertResourceDetails(t, tt.want, got.Details)
+				assert.NotEmpty(t, got.GetSigningKey())
+			}
 		})
 	}
 }
@@ -217,11 +219,15 @@ func TestServer_PatchTarget(t *testing.T) {
 		ctx context.Context
 		req *action.PatchTargetRequest
 	}
+	type want struct {
+		details    *resource_object.Details
+		signingKey bool
+	}
 	tests := []struct {
 		name    string
 		prepare func(request *action.PatchTargetRequest) error
 		args    args
-		want    *resource_object.Details
+		want    want
 		wantErr bool
 	}{
 		{
@@ -272,7 +278,8 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
-			want: &resource_object.Details{
+			want: want{
+				details: &resource_object.Details{
 					Changed: timestamppb.Now(),
 					Owner: &object.Owner{
 						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
@@ -280,6 +287,33 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
+		},
+		{
+			name: "regenerate signingkey, ok",
+			prepare: func(request *action.PatchTargetRequest) error {
+				targetID := instance.CreateTarget(isolatedIAMOwnerCTX, t, "", "https://example.com", domain.TargetTypeWebhook, false).GetDetails().GetId()
+				request.Id = targetID
+				return nil
+			},
+			args: args{
+				ctx: isolatedIAMOwnerCTX,
+				req: &action.PatchTargetRequest{
+					Target: &action.PatchTarget{
+						ExpirationSigningKey: durationpb.New(0 * time.Second),
+					},
+				},
+			},
+			want: want{
+				details: &resource_object.Details{
+					Changed: timestamppb.Now(),
+					Owner: &object.Owner{
+						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
+						Id:   instance.ID(),
+					},
+				},
+				signingKey: true,
+			},
+		},
 		{
 			name: "change type, ok",
 			prepare: func(request *action.PatchTargetRequest) error {
@@ -299,7 +333,8 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
-			want: &resource_object.Details{
+			want: want{
+				details: &resource_object.Details{
 					Changed: timestamppb.Now(),
 					Owner: &object.Owner{
 						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
@@ -307,6 +342,7 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
+		},
 		{
 			name: "change url, ok",
 			prepare: func(request *action.PatchTargetRequest) error {
@@ -322,7 +358,8 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
-			want: &resource_object.Details{
+			want: want{
+				details: &resource_object.Details{
 					Changed: timestamppb.Now(),
 					Owner: &object.Owner{
 						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
@@ -330,6 +367,7 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
+		},
 		{
 			name: "change timeout, ok",
 			prepare: func(request *action.PatchTargetRequest) error {
@@ -345,7 +383,8 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
-			want: &resource_object.Details{
+			want: want{
+				details: &resource_object.Details{
 					Changed: timestamppb.Now(),
 					Owner: &object.Owner{
 						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
@@ -353,6 +392,7 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
+		},
 		{
 			name: "change type async, ok",
 			prepare: func(request *action.PatchTargetRequest) error {
@@ -370,7 +410,8 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
-			want: &resource_object.Details{
+			want: want{
+				details: &resource_object.Details{
 					Changed: timestamppb.Now(),
 					Owner: &object.Owner{
 						Type: object.OwnerType_OWNER_TYPE_INSTANCE,
@@ -378,6 +419,7 @@ func TestServer_PatchTarget(t *testing.T) {
 					},
 				},
 			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -387,11 +429,14 @@ func TestServer_PatchTarget(t *testing.T) {
 			instance.Client.ActionV3Alpha.PatchTarget(tt.args.ctx, tt.args.req)
 			got, err := instance.Client.ActionV3Alpha.PatchTarget(tt.args.ctx, tt.args.req)
 			if tt.wantErr {
-				require.Error(t, err)
+				assert.Error(t, err)
-				return
+			} else {
+				assert.NoError(t, err)
+				integration.AssertResourceDetails(t, tt.want.details, got.Details)
+				if tt.want.signingKey {
+					assert.NotEmpty(t, got.SigningKey)
+				}
 			}
-			require.NoError(t, err)
-			integration.AssertResourceDetails(t, tt.want, got.Details)
 		})
 	}
 }
@@ -443,11 +488,12 @@ func TestServer_DeleteTarget(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			got, err := instance.Client.ActionV3Alpha.DeleteTarget(tt.ctx, tt.req)
 			if tt.wantErr {
-				require.Error(t, err)
+				assert.Error(t, err)
 				return
-			}
+			} else {
-			require.NoError(t, err)
+				assert.NoError(t, err)
 				integration.AssertResourceDetails(t, tt.want, got.Details)
+			}
 		})
 	}
 }

internal/api/grpc/resources/action/v3alpha/query.go

@@ -97,6 +97,7 @@ func targetToPb(t *query.Target) *action.GetTarget {
 			Timeout:  durationpb.New(t.Timeout),
 			Endpoint: t.Endpoint,
 		},
+		SigningKey: t.SigningKey,
 	}
 	switch t.TargetType {
 	case domain.TargetTypeWebhook:

internal/api/grpc/resources/action/v3alpha/target.go

@@ -26,6 +26,7 @@ func (s *Server) CreateTarget(ctx context.Context, req *action.CreateTargetReque
 	}
 	return &action.CreateTargetResponse{
 		Details:    resource_object.DomainToDetailsPb(details, object.OwnerType_OWNER_TYPE_INSTANCE, instanceID),
+		SigningKey: add.SigningKey,
 	}, nil
 }
 
@@ -34,12 +35,14 @@ func (s *Server) PatchTarget(ctx context.Context, req *action.PatchTargetRequest
 		return nil, err
 	}
 	instanceID := authz.GetInstance(ctx).InstanceID()
-	details, err := s.command.ChangeTarget(ctx, patchTargetToCommand(req), instanceID)
+	patch := patchTargetToCommand(req)
+	details, err := s.command.ChangeTarget(ctx, patch, instanceID)
 	if err != nil {
 		return nil, err
 	}
 	return &action.PatchTargetResponse{
 		Details:    resource_object.DomainToDetailsPb(details, object.OwnerType_OWNER_TYPE_INSTANCE, instanceID),
+		SigningKey: patch.SigningKey,
 	}, nil
 }
 
@@ -83,6 +86,12 @@ func createTargetToCommand(req *action.CreateTargetRequest) *command.AddTarget {
 }
 
 func patchTargetToCommand(req *action.PatchTargetRequest) *command.ChangeTarget {
+	expirationSigningKey := false
+	// TODO handle expiration, currently only immediate expiration is supported
+	if req.GetTarget().GetExpirationSigningKey() != nil {
+		expirationSigningKey = true
+	}
+
 	reqTarget := req.GetTarget()
 	if reqTarget == nil {
 		return nil
@@ -93,6 +102,7 @@ func patchTargetToCommand(req *action.PatchTargetRequest) *command.ChangeTarget
 		},
 		Name:                 reqTarget.Name,
 		Endpoint:             reqTarget.Endpoint,
+		ExpirationSigningKey: expirationSigningKey,
 	}
 	if reqTarget.TargetType != nil {
 		switch t := reqTarget.GetTargetType().(type) {

internal/api/grpc/server/middleware/execution_interceptor_test.go

@@ -26,6 +26,7 @@ type mockExecutionTarget struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+	SigningKey       string
 }
 
 func (e *mockExecutionTarget) SetEndpoint(endpoint string) {
@@ -49,6 +50,9 @@ func (e *mockExecutionTarget) GetTargetID() string {
 func (e *mockExecutionTarget) GetExecutionID() string {
 	return e.ExecutionID
 }
+func (e *mockExecutionTarget) GetSigningKey() string {
+	return e.SigningKey
+}
 
 type mockContentRequest struct {
 	Content string
@@ -157,6 +161,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetID:    "target",
 						TargetType:  domain.TargetTypeCall,
 						Timeout:     time.Minute,
+						SigningKey:  "signingkey",
 					},
 				},
 				targets: []target{
@@ -186,6 +191,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 
@@ -216,6 +222,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Second,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -245,6 +252,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Second,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -269,6 +277,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -297,6 +306,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetID:    "target",
 						TargetType:  domain.TargetTypeAsync,
 						Timeout:     time.Second,
+						SigningKey:  "signingkey",
 					},
 				},
 				targets: []target{
@@ -325,6 +335,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetID:    "target",
 						TargetType:  domain.TargetTypeAsync,
 						Timeout:     time.Minute,
+						SigningKey:  "signingkey",
 					},
 				},
 				targets: []target{
@@ -354,6 +365,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeWebhook,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -382,6 +394,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeWebhook,
 						Timeout:          time.Second,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -411,6 +424,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeWebhook,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -440,6 +454,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 					&mockExecutionTarget{
 						InstanceID:       "instance",
@@ -448,6 +463,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 					&mockExecutionTarget{
 						InstanceID:       "instance",
@@ -456,6 +472,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 
@@ -498,6 +515,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 					&mockExecutionTarget{
 						InstanceID:       "instance",
@@ -506,6 +524,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Second,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 					&mockExecutionTarget{
 						InstanceID:       "instance",
@@ -514,6 +533,7 @@ func Test_executeTargetsForGRPCFullMethod_request(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Second,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -692,6 +712,7 @@ func Test_executeTargetsForGRPCFullMethod_response(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{
@@ -721,6 +742,7 @@ func Test_executeTargetsForGRPCFullMethod_response(t *testing.T) {
 						TargetType:       domain.TargetTypeCall,
 						Timeout:          time.Minute,
 						InterruptOnError: true,
+						SigningKey:       "signingkey",
 					},
 				},
 				targets: []target{

internal/command/action_v2_execution_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
 	"github.com/zitadel/zitadel/internal/repository/execution"
@@ -172,6 +173,12 @@ func TestCommands_SetExecutionRequest(t *testing.T) {
 								"https://example.com",
 								time.Second,
 								true,
+								&crypto.CryptoValue{
+									CryptoType: crypto.TypeEncryption,
+									Algorithm:  "enc",
+									KeyID:      "id",
+									Crypted:    []byte("12345678"),
+								},
 							),
 						),
 					),
@@ -221,6 +228,12 @@ func TestCommands_SetExecutionRequest(t *testing.T) {
 								"https://example.com",
 								time.Second,
 								true,
+								&crypto.CryptoValue{
+									CryptoType: crypto.TypeEncryption,
+									Algorithm:  "enc",
+									KeyID:      "id",
+									Crypted:    []byte("12345678"),
+								},
 							),
 						),
 					),
@@ -270,6 +283,12 @@ func TestCommands_SetExecutionRequest(t *testing.T) {
 								"https://example.com",
 								time.Second,
 								true,
+								&crypto.CryptoValue{
+									CryptoType: crypto.TypeEncryption,
+									Algorithm:  "enc",
+									KeyID:      "id",
+									Crypted:    []byte("12345678"),
+								},
 							),
 						),
 					),
@@ -836,6 +855,12 @@ func TestCommands_SetExecutionResponse(t *testing.T) {
 							"https://example.com",
 							time.Second,
 							true,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "enc",
+								KeyID:      "id",
+								Crypted:    []byte("12345678"),
+							},
 						),
 					),
 					expectPushFailed(
@@ -930,6 +955,12 @@ func TestCommands_SetExecutionResponse(t *testing.T) {
 								"https://example.com",
 								time.Second,
 								true,
+								&crypto.CryptoValue{
+									CryptoType: crypto.TypeEncryption,
+									Algorithm:  "enc",
+									KeyID:      "id",
+									Crypted:    []byte("12345678"),
+								},
 							),
 						),
 					),

internal/command/action_v2_target.go

@@ -5,6 +5,8 @@ import (
 	"net/url"
 	"time"
 
+	"github.com/zitadel/zitadel/internal/command/preparation"
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore/v1/models"
 	"github.com/zitadel/zitadel/internal/repository/target"
@@ -19,6 +21,8 @@ type AddTarget struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+
+	SigningKey string
 }
 
 func (a *AddTarget) IsValid() error {
@@ -58,7 +62,11 @@ func (c *Commands) AddTarget(ctx context.Context, add *AddTarget, resourceOwner
 	if wm.State.Exists() {
 		return nil, zerrors.ThrowAlreadyExists(nil, "INSTANCE-9axkz0jvzm", "Errors.Target.AlreadyExists")
 	}
-
+	code, err := c.newSigningKey(ctx, c.eventstore.Filter, c.targetEncryption) //nolint
+	if err != nil {
+		return nil, err
+	}
+	add.SigningKey = code.PlainCode()
 	pushedEvents, err := c.eventstore.Push(ctx, target.NewAddedEvent(
 		ctx,
 		TargetAggregateFromWriteModel(&wm.WriteModel),
@@ -67,6 +75,7 @@ func (c *Commands) AddTarget(ctx context.Context, add *AddTarget, resourceOwner
 		add.Endpoint,
 		add.Timeout,
 		add.InterruptOnError,
+		code.Crypted,
 	))
 	if err != nil {
 		return nil, err
@@ -85,6 +94,9 @@ type ChangeTarget struct {
 	Endpoint         *string
 	Timeout          *time.Duration
 	InterruptOnError *bool
+
+	ExpirationSigningKey bool
+	SigningKey           *string
 }
 
 func (a *ChangeTarget) IsValid() error {
@@ -120,6 +132,17 @@ func (c *Commands) ChangeTarget(ctx context.Context, change *ChangeTarget, resou
 	if !existing.State.Exists() {
 		return nil, zerrors.ThrowNotFound(nil, "COMMAND-xj14f2cccn", "Errors.Target.NotFound")
 	}
+
+	var changedSigningKey *crypto.CryptoValue
+	if change.ExpirationSigningKey {
+		code, err := c.newSigningKey(ctx, c.eventstore.Filter, c.targetEncryption) //nolint
+		if err != nil {
+			return nil, err
+		}
+		changedSigningKey = code.Crypted
+		change.SigningKey = &code.Plain
+	}
+
 	changedEvent := existing.NewChangedEvent(
 		ctx,
 		TargetAggregateFromWriteModel(&existing.WriteModel),
@@ -127,7 +150,9 @@ func (c *Commands) ChangeTarget(ctx context.Context, change *ChangeTarget, resou
 		change.TargetType,
 		change.Endpoint,
 		change.Timeout,
-		change.InterruptOnError)
+		change.InterruptOnError,
+		changedSigningKey,
+	)
 	if changedEvent == nil {
 		return writeModelToObjectDetails(&existing.WriteModel), nil
 	}
@@ -184,3 +209,7 @@ func (c *Commands) getTargetWriteModelByID(ctx context.Context, id string, resou
 	}
 	return wm, nil
 }
+
+func (c *Commands) newSigningKey(ctx context.Context, filter preparation.FilterToQueryReducer, alg crypto.EncryptionAlgorithm) (*EncryptedCode, error) {
+	return c.newEncryptedCodeWithDefault(ctx, filter, domain.SecretGeneratorTypeSigningKey, alg, c.defaultSecretGenerators.SigningKey)
+}

internal/command/action_v2_target_model.go

@@ -5,6 +5,7 @@ import (
 	"slices"
 	"time"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
 	"github.com/zitadel/zitadel/internal/repository/target"
@@ -18,6 +19,7 @@ type TargetWriteModel struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+	SigningKey       *crypto.CryptoValue
 
 	State domain.TargetState
 }
@@ -41,6 +43,7 @@ func (wm *TargetWriteModel) Reduce() error {
 			wm.Endpoint = e.Endpoint
 			wm.Timeout = e.Timeout
 			wm.State = domain.TargetActive
+			wm.SigningKey = e.SigningKey
 		case *target.ChangedEvent:
 			if e.Name != nil {
 				wm.Name = *e.Name
@@ -57,6 +60,9 @@ func (wm *TargetWriteModel) Reduce() error {
 			if e.InterruptOnError != nil {
 				wm.InterruptOnError = *e.InterruptOnError
 			}
+			if e.SigningKey != nil {
+				wm.SigningKey = e.SigningKey
+			}
 		case *target.RemovedEvent:
 			wm.State = domain.TargetRemoved
 		}
@@ -84,6 +90,7 @@ func (wm *TargetWriteModel) NewChangedEvent(
 	endpoint *string,
 	timeout *time.Duration,
 	interruptOnError *bool,
+	signingKey *crypto.CryptoValue,
 ) *target.ChangedEvent {
 	changes := make([]target.Changes, 0)
 	if name != nil && wm.Name != *name {
@@ -101,6 +108,10 @@ func (wm *TargetWriteModel) NewChangedEvent(
 	if interruptOnError != nil && wm.InterruptOnError != *interruptOnError {
 		changes = append(changes, target.ChangeInterruptOnError(*interruptOnError))
 	}
+	// if signingkey is set, update it as it is encrypted
+	if signingKey != nil {
+		changes = append(changes, target.ChangeSigningKey(signingKey))
+	}
 	if len(changes) == 0 {
 		return nil
 	}

internal/command/action_v2_target_model_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
 	"github.com/zitadel/zitadel/internal/repository/target"
@@ -20,6 +21,12 @@ func targetAddEvent(aggID, resourceOwner string) *target.AddedEvent {
 		"https://example.com",
 		time.Second,
 		false,
+		&crypto.CryptoValue{
+			CryptoType: crypto.TypeEncryption,
+			Algorithm:  "enc",
+			KeyID:      "id",
+			Crypted:    []byte("12345678"),
+		},
 	)
 }
 

internal/command/action_v2_target_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/muhlemmer/gu"
 	"github.com/stretchr/testify/assert"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
 	"github.com/zitadel/zitadel/internal/eventstore/v1/models"
@@ -21,6 +22,8 @@ func TestCommands_AddTarget(t *testing.T) {
 	type fields struct {
 		eventstore                  func(t *testing.T) *eventstore.Eventstore
 		idGenerator                 id.Generator
+		newEncryptedCodeWithDefault encryptedCodeWithDefaultFunc
+		defaultSecretGenerators     *SecretGenerators
 	}
 	type args struct {
 		ctx           context.Context
@@ -132,10 +135,18 @@ func TestCommands_AddTarget(t *testing.T) {
 							"https://example.com",
 							time.Second,
 							false,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "enc",
+								KeyID:      "id",
+								Crypted:    []byte("12345678"),
+							},
 						),
 					),
 				),
 				idGenerator:                 mock.ExpectID(t, "id1"),
+				newEncryptedCodeWithDefault: mockEncryptedCodeWithDefault("12345678", time.Hour),
+				defaultSecretGenerators:     &SecretGenerators{},
 			},
 			args{
 				ctx: context.Background(),
@@ -187,6 +198,8 @@ func TestCommands_AddTarget(t *testing.T) {
 					),
 				),
 				idGenerator:                 mock.ExpectID(t, "id1"),
+				newEncryptedCodeWithDefault: mockEncryptedCodeWithDefault("12345678", time.Hour),
+				defaultSecretGenerators:     &SecretGenerators{},
 			},
 			args{
 				ctx: context.Background(),
@@ -220,6 +233,8 @@ func TestCommands_AddTarget(t *testing.T) {
 					),
 				),
 				idGenerator:                 mock.ExpectID(t, "id1"),
+				newEncryptedCodeWithDefault: mockEncryptedCodeWithDefault("12345678", time.Hour),
+				defaultSecretGenerators:     &SecretGenerators{},
 			},
 			args{
 				ctx: context.Background(),
@@ -246,6 +261,8 @@ func TestCommands_AddTarget(t *testing.T) {
 			c := &Commands{
 				eventstore:                  tt.fields.eventstore(t),
 				idGenerator:                 tt.fields.idGenerator,
+				newEncryptedCodeWithDefault: tt.fields.newEncryptedCodeWithDefault,
+				defaultSecretGenerators:     tt.fields.defaultSecretGenerators,
 			}
 			details, err := c.AddTarget(tt.args.ctx, tt.args.add, tt.args.resourceOwner)
 			if tt.res.err == nil {
@@ -265,6 +282,8 @@ func TestCommands_AddTarget(t *testing.T) {
 func TestCommands_ChangeTarget(t *testing.T) {
 	type fields struct {
 		eventstore                  func(t *testing.T) *eventstore.Eventstore
+		newEncryptedCodeWithDefault encryptedCodeWithDefaultFunc
+		defaultSecretGenerators     *SecretGenerators
 	}
 	type args struct {
 		ctx           context.Context
@@ -510,10 +529,18 @@ func TestCommands_ChangeTarget(t *testing.T) {
 								target.ChangeTargetType(domain.TargetTypeCall),
 								target.ChangeTimeout(10 * time.Second),
 								target.ChangeInterruptOnError(true),
+								target.ChangeSigningKey(&crypto.CryptoValue{
+									CryptoType: crypto.TypeEncryption,
+									Algorithm:  "enc",
+									KeyID:      "id",
+									Crypted:    []byte("12345678"),
+								}),
 							},
 						),
 					),
 				),
+				newEncryptedCodeWithDefault: mockEncryptedCodeWithDefault("12345678", time.Hour),
+				defaultSecretGenerators:     &SecretGenerators{},
 			},
 			args{
 				ctx: context.Background(),
@@ -526,6 +553,7 @@ func TestCommands_ChangeTarget(t *testing.T) {
 					TargetType:           gu.Ptr(domain.TargetTypeCall),
 					Timeout:              gu.Ptr(10 * time.Second),
 					InterruptOnError:     gu.Ptr(true),
+					ExpirationSigningKey: true,
 				},
 				resourceOwner: "instance",
 			},
@@ -541,6 +569,8 @@ func TestCommands_ChangeTarget(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			c := &Commands{
 				eventstore:                  tt.fields.eventstore(t),
+				newEncryptedCodeWithDefault: tt.fields.newEncryptedCodeWithDefault,
+				defaultSecretGenerators:     tt.fields.defaultSecretGenerators,
 			}
 			details, err := c.ChangeTarget(tt.args.ctx, tt.args.change, tt.args.resourceOwner)
 			if tt.res.err == nil {

internal/command/command.go

@@ -54,6 +54,7 @@ type Commands struct {
 	smtpEncryption                  crypto.EncryptionAlgorithm
 	smsEncryption                   crypto.EncryptionAlgorithm
 	userEncryption                  crypto.EncryptionAlgorithm
+	targetEncryption                crypto.EncryptionAlgorithm
 	userPasswordHasher              *crypto.Hasher
 	secretHasher                    *crypto.Hasher
 	machineKeySize                  int
@@ -108,7 +109,7 @@ func StartCommands(
 	externalDomain string,
 	externalSecure bool,
 	externalPort uint16,
-	idpConfigEncryption, otpEncryption, smtpEncryption, smsEncryption, userEncryption, domainVerificationEncryption, oidcEncryption, samlEncryption crypto.EncryptionAlgorithm,
+	idpConfigEncryption, otpEncryption, smtpEncryption, smsEncryption, userEncryption, domainVerificationEncryption, oidcEncryption, samlEncryption, targetEncryption crypto.EncryptionAlgorithm,
 	httpClient *http.Client,
 	permissionCheck domain.PermissionCheck,
 	sessionTokenVerifier func(ctx context.Context, sessionToken string, sessionID string, tokenID string) (err error),
@@ -153,6 +154,7 @@ func StartCommands(
 		smtpEncryption:                  smtpEncryption,
 		smsEncryption:                   smsEncryption,
 		userEncryption:                  userEncryption,
+		targetEncryption:                targetEncryption,
 		userPasswordHasher:              userPasswordHasher,
 		secretHasher:                    secretHasher,
 		machineKeySize:                  int(defaults.SecretGenerators.MachineKeySize),

internal/command/instance.go

@@ -157,6 +157,7 @@ type SecretGenerators struct {
 	OTPSMS                   *crypto.GeneratorConfig
 	OTPEmail                 *crypto.GeneratorConfig
 	InviteCode               *crypto.GeneratorConfig
+	SigningKey               *crypto.GeneratorConfig
 }
 
 type ZitadelConfig struct {

internal/domain/secret_generator.go

@@ -15,6 +15,7 @@ const (
 	SecretGeneratorTypeOTPSMS
 	SecretGeneratorTypeOTPEmail
 	SecretGeneratorTypeInviteCode
+	SecretGeneratorTypeSigningKey
 
 	secretGeneratorTypeCount
 )

internal/execution/execution.go

@@ -14,6 +14,7 @@ import (
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/telemetry/tracing"
 	"github.com/zitadel/zitadel/internal/zerrors"
+	"github.com/zitadel/zitadel/pkg/actions"
 )
 
 type ContextInfo interface {
@@ -28,6 +29,7 @@ type Target interface {
 	GetEndpoint() string
 	GetTargetType() domain.TargetType
 	GetTimeout() time.Duration
+	GetSigningKey() string
 }
 
 // CallTargets call a list of targets in order with handling of error and responses
@@ -72,13 +74,13 @@ func CallTarget(
 	switch target.GetTargetType() {
 	// get request, ignore response and return request and error for handling in list of targets
 	case domain.TargetTypeWebhook:
-		return nil, webhook(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody())
+		return nil, webhook(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody(), target.GetSigningKey())
 	// get request, return response and error
 	case domain.TargetTypeCall:
-		return Call(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody())
+		return Call(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody(), target.GetSigningKey())
 	case domain.TargetTypeAsync:
 		go func(target Target, info ContextInfoRequest) {
-			if _, err := Call(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody()); err != nil {
+			if _, err := Call(ctx, target.GetEndpoint(), target.GetTimeout(), info.GetHTTPRequestBody(), target.GetSigningKey()); err != nil {
 				logging.WithFields("target", target.GetTargetID()).OnError(err).Info(err)
 			}
 		}(target, info)
@@ -89,13 +91,13 @@ func CallTarget(
 }
 
 // webhook call a webhook, ignore the response but return the errror
-func webhook(ctx context.Context, url string, timeout time.Duration, body []byte) error {
+func webhook(ctx context.Context, url string, timeout time.Duration, body []byte, signingKey string) error {
-	_, err := Call(ctx, url, timeout, body)
+	_, err := Call(ctx, url, timeout, body, signingKey)
 	return err
 }
 
 // Call function to do a post HTTP request to a desired url with timeout
-func Call(ctx context.Context, url string, timeout time.Duration, body []byte) (_ []byte, err error) {
+func Call(ctx context.Context, url string, timeout time.Duration, body []byte, signingKey string) (_ []byte, err error) {
 	ctx, cancel := context.WithTimeout(ctx, timeout)
 	ctx, span := tracing.NewSpan(ctx)
 	defer func() {
@@ -108,6 +110,9 @@ func Call(ctx context.Context, url string, timeout time.Duration, body []byte) (
 		return nil, err
 	}
 	req.Header.Set("Content-Type", "application/json")
+	if signingKey != "" {
+		req.Header.Set(actions.SigningHeader, actions.ComputeSignatureHeader(time.Now(), body, signingKey))
+	}
 
 	client := http.DefaultClient
 	resp, err := client.Do(req)

internal/execution/execution_test.go

@@ -18,6 +18,7 @@ import (
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/execution"
 	"github.com/zitadel/zitadel/internal/zerrors"
+	"github.com/zitadel/zitadel/pkg/actions"
 )
 
 func Test_Call(t *testing.T) {
@@ -29,6 +30,7 @@ func Test_Call(t *testing.T) {
 		body       []byte
 		respBody   []byte
 		statusCode int
+		signingKey string
 	}
 	type res struct {
 		body    []byte
@@ -84,6 +86,22 @@ func Test_Call(t *testing.T) {
 				body: []byte("{\"response\": \"values\"}"),
 			},
 		},
+		{
+			"ok, signed",
+			args{
+				ctx:        context.Background(),
+				timeout:    time.Minute,
+				sleep:      time.Second,
+				method:     http.MethodPost,
+				body:       []byte("{\"request\": \"values\"}"),
+				respBody:   []byte("{\"response\": \"values\"}"),
+				statusCode: http.StatusOK,
+				signingKey: "signingkey",
+			},
+			res{
+				body: []byte("{\"response\": \"values\"}"),
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -95,7 +113,7 @@ func Test_Call(t *testing.T) {
 					statusCode:  tt.args.statusCode,
 					respondBody: tt.args.respBody,
 				},
-				testCall(tt.args.ctx, tt.args.timeout, tt.args.body),
+				testCall(tt.args.ctx, tt.args.timeout, tt.args.body, tt.args.signingKey),
 			)
 			if tt.res.wantErr {
 				assert.Error(t, err)
@@ -186,6 +204,29 @@ func Test_CallTarget(t *testing.T) {
 				body: nil,
 			},
 		},
+		{
+			"webhook, signed, ok",
+			args{
+				ctx:  context.Background(),
+				info: requestContextInfo1,
+				server: &callTestServer{
+					timeout:     time.Second,
+					method:      http.MethodPost,
+					expectBody:  []byte("{\"request\":{\"request\":\"content1\"}}"),
+					respondBody: []byte("{\"request\":\"content2\"}"),
+					statusCode:  http.StatusOK,
+					signingKey:  "signingkey",
+				},
+				target: &mockTarget{
+					TargetType: domain.TargetTypeWebhook,
+					Timeout:    time.Minute,
+					SigningKey: "signingkey",
+				},
+			},
+			res{
+				body: nil,
+			},
+		},
 		{
 			"request response, error",
 			args{
@@ -228,6 +269,29 @@ func Test_CallTarget(t *testing.T) {
 				body: []byte("{\"request\":\"content2\"}"),
 			},
 		},
+		{
+			"request response, signed, ok",
+			args{
+				ctx:  context.Background(),
+				info: requestContextInfo1,
+				server: &callTestServer{
+					timeout:     time.Second,
+					method:      http.MethodPost,
+					expectBody:  []byte("{\"request\":{\"request\":\"content1\"}}"),
+					respondBody: []byte("{\"request\":\"content2\"}"),
+					statusCode:  http.StatusOK,
+					signingKey:  "signingkey",
+				},
+				target: &mockTarget{
+					TargetType: domain.TargetTypeCall,
+					Timeout:    time.Minute,
+					SigningKey: "signingkey",
+				},
+			},
+			res{
+				body: []byte("{\"request\":\"content2\"}"),
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -392,6 +456,7 @@ type mockTarget struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+	SigningKey       string
 }
 
 func (e *mockTarget) GetTargetID() string {
@@ -409,6 +474,9 @@ func (e *mockTarget) GetTargetType() domain.TargetType {
 func (e *mockTarget) GetTimeout() time.Duration {
 	return e.Timeout
 }
+func (e *mockTarget) GetSigningKey() string {
+	return e.SigningKey
+}
 
 type callTestServer struct {
 	method      string
@@ -416,6 +484,7 @@ type callTestServer struct {
 	timeout     time.Duration
 	statusCode  int
 	respondBody []byte
+	signingKey  string
 }
 
 func testServers(
@@ -447,7 +516,7 @@ func listen(
 	c *callTestServer,
 ) (url string, close func()) {
 	handler := func(w http.ResponseWriter, r *http.Request) {
-		checkRequest(t, r, c.method, c.expectBody)
+		checkRequest(t, r, c.method, c.expectBody, c.signingKey)
 
 		if c.statusCode != http.StatusOK {
 			http.Error(w, "error", c.statusCode)
@@ -466,16 +535,19 @@ func listen(
 	return server.URL, server.Close
 }
 
-func checkRequest(t *testing.T, sent *http.Request, method string, expectedBody []byte) {
+func checkRequest(t *testing.T, sent *http.Request, method string, expectedBody []byte, signingKey string) {
 	sentBody, err := io.ReadAll(sent.Body)
 	require.NoError(t, err)
 	require.Equal(t, expectedBody, sentBody)
 	require.Equal(t, method, sent.Method)
+	if signingKey != "" {
+		require.NoError(t, actions.ValidatePayload(sentBody, sent.Header.Get(actions.SigningHeader), signingKey))
+	}
 }
 
-func testCall(ctx context.Context, timeout time.Duration, body []byte) func(string) ([]byte, error) {
+func testCall(ctx context.Context, timeout time.Duration, body []byte, signingKey string) func(string) ([]byte, error) {
 	return func(url string) ([]byte, error) {
-		return execution.Call(ctx, url, timeout, body)
+		return execution.Call(ctx, url, timeout, body, signingKey)
 	}
 }
 

internal/query/execution.go

@@ -11,6 +11,7 @@ import (
 	sq "github.com/Masterminds/squirrel"
 
 	"github.com/zitadel/zitadel/internal/api/authz"
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/database"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/query/projection"
@@ -175,6 +176,11 @@ func (q *Queries) TargetsByExecutionID(ctx context.Context, ids []string) (execu
 		instanceID,
 		database.TextArray[string](ids),
 	)
+	for i := range execution {
+		if err := execution[i].decryptSigningKey(q.targetEncryptionAlgorithm); err != nil {
+			return nil, err
+		}
+	}
 	return execution, err
 }
 
@@ -205,6 +211,11 @@ func (q *Queries) TargetsByExecutionIDs(ctx context.Context, ids1, ids2 []string
 		database.TextArray[string](ids1),
 		database.TextArray[string](ids2),
 	)
+	for i := range execution {
+		if err := execution[i].decryptSigningKey(q.targetEncryptionAlgorithm); err != nil {
+			return nil, err
+		}
+	}
 	return execution, err
 }
 
@@ -352,6 +363,8 @@ type ExecutionTarget struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+	signingKey       *crypto.CryptoValue
+	SigningKey       string
 }
 
 func (e *ExecutionTarget) GetExecutionID() string {
@@ -372,6 +385,21 @@ func (e *ExecutionTarget) GetTargetType() domain.TargetType {
 func (e *ExecutionTarget) GetTimeout() time.Duration {
 	return e.Timeout
 }
+func (e *ExecutionTarget) GetSigningKey() string {
+	return e.SigningKey
+}
+
+func (t *ExecutionTarget) decryptSigningKey(alg crypto.EncryptionAlgorithm) error {
+	if t.signingKey == nil {
+		return nil
+	}
+	keyValue, err := crypto.DecryptString(t.signingKey, alg)
+	if err != nil {
+		return zerrors.ThrowInternal(err, "QUERY-bxevy3YXwy", "Errors.Internal")
+	}
+	t.SigningKey = keyValue
+	return nil
+}
 
 func scanExecutionTargets(rows *sql.Rows) ([]*ExecutionTarget, error) {
 	targets := make([]*ExecutionTarget, 0)
@@ -386,6 +414,7 @@ func scanExecutionTargets(rows *sql.Rows) ([]*ExecutionTarget, error) {
 			endpoint         = &sql.NullString{}
 			timeout          = &sql.NullInt64{}
 			interruptOnError = &sql.NullBool{}
+			signingKey       = &crypto.CryptoValue{}
 		)
 
 		err := rows.Scan(
@@ -396,6 +425,7 @@ func scanExecutionTargets(rows *sql.Rows) ([]*ExecutionTarget, error) {
 			endpoint,
 			timeout,
 			interruptOnError,
+			signingKey,
 		)
 
 		if err != nil {
@@ -409,6 +439,7 @@ func scanExecutionTargets(rows *sql.Rows) ([]*ExecutionTarget, error) {
 		target.Endpoint = endpoint.String
 		target.Timeout = time.Duration(timeout.Int64)
 		target.InterruptOnError = interruptOnError.Bool
+		target.signingKey = signingKey
 
 		targets = append(targets, target)
 	}

internal/query/projection/target.go

@@ -11,7 +11,7 @@ import (
 )
 
 const (
-	TargetTable               = "projections.targets1"
+	TargetTable               = "projections.targets2"
 	TargetIDCol               = "id"
 	TargetCreationDateCol     = "creation_date"
 	TargetChangeDateCol       = "change_date"
@@ -23,6 +23,7 @@ const (
 	TargetEndpointCol         = "endpoint"
 	TargetTimeoutCol          = "timeout"
 	TargetInterruptOnErrorCol = "interrupt_on_error"
+	TargetSigningKey          = "signing_key"
 )
 
 type targetProjection struct{}
@@ -49,6 +50,7 @@ func (*targetProjection) Init() *old_handler.Check {
 			handler.NewColumn(TargetEndpointCol, handler.ColumnTypeText),
 			handler.NewColumn(TargetTimeoutCol, handler.ColumnTypeInt64),
 			handler.NewColumn(TargetInterruptOnErrorCol, handler.ColumnTypeBool),
+			handler.NewColumn(TargetSigningKey, handler.ColumnTypeJSONB, handler.Nullable()),
 		},
 			handler.NewPrimaryKey(TargetInstanceIDCol, TargetIDCol),
 		),
@@ -105,6 +107,7 @@ func (p *targetProjection) reduceTargetAdded(event eventstore.Event) (*handler.S
 			handler.NewCol(TargetTargetType, e.TargetType),
 			handler.NewCol(TargetTimeoutCol, e.Timeout),
 			handler.NewCol(TargetInterruptOnErrorCol, e.InterruptOnError),
+			handler.NewCol(TargetSigningKey, e.SigningKey),
 		},
 	), nil
 }
@@ -134,6 +137,9 @@ func (p *targetProjection) reduceTargetChanged(event eventstore.Event) (*handler
 	if e.InterruptOnError != nil {
 		values = append(values, handler.NewCol(TargetInterruptOnErrorCol, *e.InterruptOnError))
 	}
+	if e.SigningKey != nil {
+		values = append(values, handler.NewCol(TargetSigningKey, e.SigningKey))
+	}
 	return handler.NewUpdateStatement(
 		e,
 		values,

internal/query/projection/target_test.go

@@ -29,7 +29,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 					testEvent(
 						target.AddedEventType,
 						target.AggregateType,
-						[]byte(`{"name": "name", "targetType":0, "endpoint":"https://example.com", "timeout": 3000000000, "async": true, "interruptOnError": true}`),
+						[]byte(`{"name": "name", "targetType":0, "endpoint":"https://example.com", "timeout": 3000000000, "async": true, "interruptOnError": true, "signingKey": { "cryptoType": 0, "algorithm": "RSA-265", "keyId": "key-id" }}`),
 					),
 					eventstore.GenericEventMapper[target.AddedEvent],
 				),
@@ -41,7 +41,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 				executer: &testExecuter{
 					executions: []execution{
 						{
-							expectedStmt: "INSERT INTO projections.targets1 (instance_id, resource_owner, id, creation_date, change_date, sequence, name, endpoint, target_type, timeout, interrupt_on_error) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)",
+							expectedStmt: "INSERT INTO projections.targets2 (instance_id, resource_owner, id, creation_date, change_date, sequence, name, endpoint, target_type, timeout, interrupt_on_error, signing_key) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12)",
 							expectedArgs: []interface{}{
 								"instance-id",
 								"ro-id",
@@ -54,6 +54,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 								domain.TargetTypeWebhook,
 								3 * time.Second,
 								true,
+								anyArg{},
 							},
 						},
 					},
@@ -67,7 +68,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 					testEvent(
 						target.ChangedEventType,
 						target.AggregateType,
-						[]byte(`{"name": "name2", "targetType":0, "endpoint":"https://example.com", "timeout": 3000000000, "async": true, "interruptOnError": true}`),
+						[]byte(`{"name": "name2", "targetType":0, "endpoint":"https://example.com", "timeout": 3000000000, "async": true, "interruptOnError": true, "signingKey": { "cryptoType": 0, "algorithm": "RSA-265", "keyId": "key-id" }}`),
 					),
 					eventstore.GenericEventMapper[target.ChangedEvent],
 				),
@@ -79,7 +80,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 				executer: &testExecuter{
 					executions: []execution{
 						{
-							expectedStmt: "UPDATE projections.targets1 SET (change_date, sequence, resource_owner, name, target_type, endpoint, timeout, interrupt_on_error) = ($1, $2, $3, $4, $5, $6, $7, $8) WHERE (instance_id = $9) AND (id = $10)",
+							expectedStmt: "UPDATE projections.targets2 SET (change_date, sequence, resource_owner, name, target_type, endpoint, timeout, interrupt_on_error, signing_key) = ($1, $2, $3, $4, $5, $6, $7, $8, $9) WHERE (instance_id = $10) AND (id = $11)",
 							expectedArgs: []interface{}{
 								anyArg{},
 								uint64(15),
@@ -89,6 +90,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 								"https://example.com",
 								3 * time.Second,
 								true,
+								anyArg{},
 								"instance-id",
 								"agg-id",
 							},
@@ -116,7 +118,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 				executer: &testExecuter{
 					executions: []execution{
 						{
-							expectedStmt: "DELETE FROM projections.targets1 WHERE (instance_id = $1) AND (id = $2)",
+							expectedStmt: "DELETE FROM projections.targets2 WHERE (instance_id = $1) AND (id = $2)",
 							expectedArgs: []interface{}{
 								"instance-id",
 								"agg-id",
@@ -145,7 +147,7 @@ func TestTargetProjection_reduces(t *testing.T) {
 				executer: &testExecuter{
 					executions: []execution{
 						{
-							expectedStmt: "DELETE FROM projections.targets1 WHERE (instance_id = $1)",
+							expectedStmt: "DELETE FROM projections.targets2 WHERE (instance_id = $1)",
 							expectedArgs: []interface{}{
 								"agg-id",
 							},

internal/query/query.go

@@ -31,6 +31,7 @@ type Queries struct {
 
 	keyEncryptionAlgorithm    crypto.EncryptionAlgorithm
 	idpConfigEncryption       crypto.EncryptionAlgorithm
+	targetEncryptionAlgorithm crypto.EncryptionAlgorithm
 	sessionTokenVerifier      func(ctx context.Context, sessionToken string, sessionID string, tokenID string) (err error)
 	checkPermission           domain.PermissionCheck
 
@@ -52,7 +53,7 @@ func StartQueries(
 	cacheConnectors connector.Connectors,
 	projections projection.Config,
 	defaults sd.SystemDefaults,
-	idpConfigEncryption, otpEncryption, keyEncryptionAlgorithm, certEncryptionAlgorithm crypto.EncryptionAlgorithm,
+	idpConfigEncryption, otpEncryption, keyEncryptionAlgorithm, certEncryptionAlgorithm, targetEncryptionAlgorithm crypto.EncryptionAlgorithm,
 	zitadelRoles []authz.RoleMapping,
 	sessionTokenVerifier func(ctx context.Context, sessionToken string, sessionID string, tokenID string) (err error),
 	permissionCheck func(q *Queries) domain.PermissionCheck,
@@ -70,6 +71,7 @@ func StartQueries(
 		zitadelRoles:                        zitadelRoles,
 		keyEncryptionAlgorithm:              keyEncryptionAlgorithm,
 		idpConfigEncryption:                 idpConfigEncryption,
+		targetEncryptionAlgorithm:           targetEncryptionAlgorithm,
 		sessionTokenVerifier:                sessionTokenVerifier,
 		multifactors: domain.MultifactorConfigs{
 			OTP: domain.OTPConfig{

internal/query/target.go

@@ -9,6 +9,7 @@ import (
 	sq "github.com/Masterminds/squirrel"
 
 	"github.com/zitadel/zitadel/internal/api/authz"
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/query/projection"
 	"github.com/zitadel/zitadel/internal/zerrors"
@@ -59,6 +60,10 @@ var (
 		name:  projection.TargetInterruptOnErrorCol,
 		table: targetTable,
 	}
+	TargetColumnSigningKey = Column{
+		name:  projection.TargetSigningKey,
+		table: targetTable,
+	}
 )
 
 type Targets struct {
@@ -78,6 +83,20 @@ type Target struct {
 	Endpoint         string
 	Timeout          time.Duration
 	InterruptOnError bool
+	signingKey       *crypto.CryptoValue
+	SigningKey       string
+}
+
+func (t *Target) decryptSigningKey(alg crypto.EncryptionAlgorithm) error {
+	if t.signingKey == nil {
+		return nil
+	}
+	keyValue, err := crypto.DecryptString(t.signingKey, alg)
+	if err != nil {
+		return zerrors.ThrowInternal(err, "QUERY-bxevy3YXwy", "Errors.Internal")
+	}
+	t.SigningKey = keyValue
+	return nil
 }
 
 type TargetSearchQueries struct {
@@ -93,21 +112,37 @@ func (q *TargetSearchQueries) toQuery(query sq.SelectBuilder) sq.SelectBuilder {
 	return query
 }
 
-func (q *Queries) SearchTargets(ctx context.Context, queries *TargetSearchQueries) (targets *Targets, err error) {
+func (q *Queries) SearchTargets(ctx context.Context, queries *TargetSearchQueries) (*Targets, error) {
 	eq := sq.Eq{
 		TargetColumnInstanceID.identifier(): authz.GetInstance(ctx).InstanceID(),
 	}
 	query, scan := prepareTargetsQuery(ctx, q.client)
-	return genericRowsQueryWithState[*Targets](ctx, q.client, targetTable, combineToWhereStmt(query, queries.toQuery, eq), scan)
+	targets, err := genericRowsQueryWithState[*Targets](ctx, q.client, targetTable, combineToWhereStmt(query, queries.toQuery, eq), scan)
+	if err != nil {
+		return nil, err
+	}
+	for i := range targets.Targets {
+		if err := targets.Targets[i].decryptSigningKey(q.targetEncryptionAlgorithm); err != nil {
+			return nil, err
+		}
+	}
+	return targets, nil
 }
 
-func (q *Queries) GetTargetByID(ctx context.Context, id string) (target *Target, err error) {
+func (q *Queries) GetTargetByID(ctx context.Context, id string) (*Target, error) {
 	eq := sq.Eq{
 		TargetColumnID.identifier():         id,
 		TargetColumnInstanceID.identifier(): authz.GetInstance(ctx).InstanceID(),
 	}
 	query, scan := prepareTargetQuery(ctx, q.client)
-	return genericRowQuery[*Target](ctx, q.client, query.Where(eq), scan)
+	target, err := genericRowQuery[*Target](ctx, q.client, query.Where(eq), scan)
+	if err != nil {
+		return nil, err
+	}
+	if err := target.decryptSigningKey(q.targetEncryptionAlgorithm); err != nil {
+		return nil, err
+	}
+	return target, nil
 }
 
 func NewTargetNameSearchQuery(method TextComparison, value string) (SearchQuery, error) {
@@ -129,6 +164,7 @@ func prepareTargetsQuery(context.Context, prepareDatabase) (sq.SelectBuilder, fu
 			TargetColumnTimeout.identifier(),
 			TargetColumnURL.identifier(),
 			TargetColumnInterruptOnError.identifier(),
+			TargetColumnSigningKey.identifier(),
 			countColumn.identifier(),
 		).From(targetTable.identifier()).
 			PlaceholderFormat(sq.Dollar),
@@ -147,6 +183,7 @@ func prepareTargetsQuery(context.Context, prepareDatabase) (sq.SelectBuilder, fu
 					&target.Timeout,
 					&target.Endpoint,
 					&target.InterruptOnError,
+					&target.signingKey,
 					&count,
 				)
 				if err != nil {
@@ -179,6 +216,7 @@ func prepareTargetQuery(context.Context, prepareDatabase) (sq.SelectBuilder, fun
 			TargetColumnTimeout.identifier(),
 			TargetColumnURL.identifier(),
 			TargetColumnInterruptOnError.identifier(),
+			TargetColumnSigningKey.identifier(),
 		).From(targetTable.identifier()).
 			PlaceholderFormat(sq.Dollar),
 		func(row *sql.Row) (*Target, error) {
@@ -193,6 +231,7 @@ func prepareTargetQuery(context.Context, prepareDatabase) (sq.SelectBuilder, fun
 				&target.Timeout,
 				&target.Endpoint,
 				&target.InterruptOnError,
+				&target.signingKey,
 			)
 			if err != nil {
 				if errors.Is(err, sql.ErrNoRows) {

internal/query/target_test.go

@@ -9,22 +9,24 @@ import (
 	"testing"
 	"time"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/zerrors"
 )
 
 var (
-	prepareTargetsStmt = `SELECT projections.targets1.id,` +
+	prepareTargetsStmt = `SELECT projections.targets2.id,` +
-		` projections.targets1.creation_date,` +
+		` projections.targets2.creation_date,` +
-		` projections.targets1.change_date,` +
+		` projections.targets2.change_date,` +
-		` projections.targets1.resource_owner,` +
+		` projections.targets2.resource_owner,` +
-		` projections.targets1.name,` +
+		` projections.targets2.name,` +
-		` projections.targets1.target_type,` +
+		` projections.targets2.target_type,` +
-		` projections.targets1.timeout,` +
+		` projections.targets2.timeout,` +
-		` projections.targets1.endpoint,` +
+		` projections.targets2.endpoint,` +
-		` projections.targets1.interrupt_on_error,` +
+		` projections.targets2.interrupt_on_error,` +
+		` projections.targets2.signing_key,` +
 		` COUNT(*) OVER ()` +
-		` FROM projections.targets1`
+		` FROM projections.targets2`
 	prepareTargetsCols = []string{
 		"id",
 		"creation_date",
@@ -35,19 +37,21 @@ var (
 		"timeout",
 		"endpoint",
 		"interrupt_on_error",
+		"signing_key",
 		"count",
 	}
 
-	prepareTargetStmt = `SELECT projections.targets1.id,` +
+	prepareTargetStmt = `SELECT projections.targets2.id,` +
-		` projections.targets1.creation_date,` +
+		` projections.targets2.creation_date,` +
-		` projections.targets1.change_date,` +
+		` projections.targets2.change_date,` +
-		` projections.targets1.resource_owner,` +
+		` projections.targets2.resource_owner,` +
-		` projections.targets1.name,` +
+		` projections.targets2.name,` +
-		` projections.targets1.target_type,` +
+		` projections.targets2.target_type,` +
-		` projections.targets1.timeout,` +
+		` projections.targets2.timeout,` +
-		` projections.targets1.endpoint,` +
+		` projections.targets2.endpoint,` +
-		` projections.targets1.interrupt_on_error` +
+		` projections.targets2.interrupt_on_error,` +
-		` FROM projections.targets1`
+		` projections.targets2.signing_key` +
+		` FROM projections.targets2`
 	prepareTargetCols = []string{
 		"id",
 		"creation_date",
@@ -58,6 +62,7 @@ var (
 		"timeout",
 		"endpoint",
 		"interrupt_on_error",
+		"signing_key",
 	}
 )
 
@@ -102,6 +107,12 @@ func Test_TargetPrepares(t *testing.T) {
 							1 * time.Second,
 							"https://example.com",
 							true,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "alg",
+								KeyID:      "encKey",
+								Crypted:    []byte("crypted"),
+							},
 						},
 					},
 				),
@@ -123,6 +134,12 @@ func Test_TargetPrepares(t *testing.T) {
 						Timeout:          1 * time.Second,
 						Endpoint:         "https://example.com",
 						InterruptOnError: true,
+						signingKey: &crypto.CryptoValue{
+							CryptoType: crypto.TypeEncryption,
+							Algorithm:  "alg",
+							KeyID:      "encKey",
+							Crypted:    []byte("crypted"),
+						},
 					},
 				},
 			},
@@ -145,6 +162,12 @@ func Test_TargetPrepares(t *testing.T) {
 							1 * time.Second,
 							"https://example.com",
 							true,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "alg",
+								KeyID:      "encKey",
+								Crypted:    []byte("crypted"),
+							},
 						},
 						{
 							"id-2",
@@ -156,6 +179,12 @@ func Test_TargetPrepares(t *testing.T) {
 							1 * time.Second,
 							"https://example.com",
 							false,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "alg",
+								KeyID:      "encKey",
+								Crypted:    []byte("crypted"),
+							},
 						},
 						{
 							"id-3",
@@ -167,6 +196,12 @@ func Test_TargetPrepares(t *testing.T) {
 							1 * time.Second,
 							"https://example.com",
 							false,
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "alg",
+								KeyID:      "encKey",
+								Crypted:    []byte("crypted"),
+							},
 						},
 					},
 				),
@@ -188,6 +223,12 @@ func Test_TargetPrepares(t *testing.T) {
 						Timeout:          1 * time.Second,
 						Endpoint:         "https://example.com",
 						InterruptOnError: true,
+						signingKey: &crypto.CryptoValue{
+							CryptoType: crypto.TypeEncryption,
+							Algorithm:  "alg",
+							KeyID:      "encKey",
+							Crypted:    []byte("crypted"),
+						},
 					},
 					{
 						ObjectDetails: domain.ObjectDetails{
@@ -201,6 +242,12 @@ func Test_TargetPrepares(t *testing.T) {
 						Timeout:          1 * time.Second,
 						Endpoint:         "https://example.com",
 						InterruptOnError: false,
+						signingKey: &crypto.CryptoValue{
+							CryptoType: crypto.TypeEncryption,
+							Algorithm:  "alg",
+							KeyID:      "encKey",
+							Crypted:    []byte("crypted"),
+						},
 					},
 					{
 						ObjectDetails: domain.ObjectDetails{
@@ -214,6 +261,12 @@ func Test_TargetPrepares(t *testing.T) {
 						Timeout:          1 * time.Second,
 						Endpoint:         "https://example.com",
 						InterruptOnError: false,
+						signingKey: &crypto.CryptoValue{
+							CryptoType: crypto.TypeEncryption,
+							Algorithm:  "alg",
+							KeyID:      "encKey",
+							Crypted:    []byte("crypted"),
+						},
 					},
 				},
 			},
@@ -270,6 +323,12 @@ func Test_TargetPrepares(t *testing.T) {
 						1 * time.Second,
 						"https://example.com",
 						true,
+						&crypto.CryptoValue{
+							CryptoType: crypto.TypeEncryption,
+							Algorithm:  "alg",
+							KeyID:      "encKey",
+							Crypted:    []byte("crypted"),
+						},
 					},
 				),
 			},
@@ -285,6 +344,12 @@ func Test_TargetPrepares(t *testing.T) {
 				Timeout:          1 * time.Second,
 				Endpoint:         "https://example.com",
 				InterruptOnError: true,
+				signingKey: &crypto.CryptoValue{
+					CryptoType: crypto.TypeEncryption,
+					Algorithm:  "alg",
+					KeyID:      "encKey",
+					Crypted:    []byte("crypted"),
+				},
 			},
 		},
 		{

internal/query/targets_by_execution_id.sql

@@ -31,9 +31,9 @@ WITH RECURSIVE
                           ON e.instance_id = p.instance_id
                               AND e.include IS NOT NULL
                               AND e.include = p.execution_id)
-select e.execution_id, e.instance_id, e.target_id, t.target_type, t.endpoint, t.timeout, t.interrupt_on_error
+select e.execution_id, e.instance_id, e.target_id, t.target_type, t.endpoint, t.timeout, t.interrupt_on_error, t.signing_key
 FROM dissolved_execution_targets e
-         JOIN projections.targets1 t
+         JOIN projections.targets2 t
               ON e.instance_id = t.instance_id
                   AND e.target_id = t.id
 WHERE "include" = ''

internal/query/targets_by_execution_ids.sql

@@ -38,9 +38,9 @@ WITH RECURSIVE
                           ON e.instance_id = p.instance_id
                               AND e.include IS NOT NULL
                               AND e.include = p.execution_id)
-select e.execution_id, e.instance_id, e.target_id, t.target_type, t.endpoint, t.timeout, t.interrupt_on_error
+select e.execution_id, e.instance_id, e.target_id, t.target_type, t.endpoint, t.timeout, t.interrupt_on_error, t.signing_key
 FROM dissolved_execution_targets e
-         JOIN projections.targets1 t
+         JOIN projections.targets2 t
               ON e.instance_id = t.instance_id
                   AND e.target_id = t.id
 WHERE "include" = ''

internal/repository/target/target.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"time"
 
+	"github.com/zitadel/zitadel/internal/crypto"
 	"github.com/zitadel/zitadel/internal/domain"
 	"github.com/zitadel/zitadel/internal/eventstore"
 )
@@ -23,6 +24,7 @@ type AddedEvent struct {
 	Endpoint         string              `json:"endpoint"`
 	Timeout          time.Duration       `json:"timeout"`
 	InterruptOnError bool                `json:"interruptOnError"`
+	SigningKey       *crypto.CryptoValue `json:"signingKey"`
 }
 
 func (e *AddedEvent) SetBaseEvent(b *eventstore.BaseEvent) {
@@ -45,12 +47,13 @@ func NewAddedEvent(
 	endpoint string,
 	timeout time.Duration,
 	interruptOnError bool,
+	signingKey *crypto.CryptoValue,
 ) *AddedEvent {
 	return &AddedEvent{
 		*eventstore.NewBaseEventForPush(
 			ctx, aggregate, AddedEventType,
 		),
-		name, targetType, endpoint, timeout, interruptOnError}
+		name, targetType, endpoint, timeout, interruptOnError, signingKey}
 }
 
 type ChangedEvent struct {
@@ -61,6 +64,7 @@ type ChangedEvent struct {
 	Endpoint         *string             `json:"endpoint,omitempty"`
 	Timeout          *time.Duration      `json:"timeout,omitempty"`
 	InterruptOnError *bool               `json:"interruptOnError,omitempty"`
+	SigningKey       *crypto.CryptoValue `json:"signingKey,omitempty"`
 
 	oldName string
 }
@@ -134,6 +138,12 @@ func ChangeInterruptOnError(interruptOnError bool) func(event *ChangedEvent) {
 	}
 }
 
+func ChangeSigningKey(signingKey *crypto.CryptoValue) func(event *ChangedEvent) {
+	return func(e *ChangedEvent) {
+		e.SigningKey = signingKey
+	}
+}
+
 type RemovedEvent struct {
 	eventstore.BaseEvent `json:"-"`
 

pkg/actions/signing.go

@@ -0,0 +1,115 @@
+package actions
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	ErrNoValidSignature = errors.New("no valid signature")
+	ErrInvalidHeader    = errors.New("webhook has invalid Zitadel-Signature header")
+	ErrNotSigned        = errors.New("webhook has no Zitadel-Signature header")
+	ErrTooOld           = errors.New("timestamp wasn't within tolerance")
+)
+
+const (
+	SigningHeader           = "ZITADEL-Signature"
+	signingTimestamp        = "t"
+	signingVersion   string = "v1"
+	DefaultTolerance        = 300 * time.Second
+	partSeparator           = ","
+)
+
+func ComputeSignatureHeader(t time.Time, payload []byte, signingKey ...string) string {
+	parts := []string{
+		fmt.Sprintf("%s=%d", signingTimestamp, t.Unix()),
+	}
+	for _, k := range signingKey {
+		parts = append(parts, fmt.Sprintf("%s=%s", signingVersion, hex.EncodeToString(computeSignature(t, payload, k))))
+	}
+	return strings.Join(parts, partSeparator)
+}
+
+func computeSignature(t time.Time, payload []byte, signingKey string) []byte {
+	mac := hmac.New(sha256.New, []byte(signingKey))
+	mac.Write([]byte(fmt.Sprintf("%d", t.Unix())))
+	mac.Write([]byte("."))
+	mac.Write(payload)
+	return mac.Sum(nil)
+}
+
+func ValidatePayload(payload []byte, header string, signingKey string) error {
+	return ValidatePayloadWithTolerance(payload, header, signingKey, DefaultTolerance)
+}
+
+func ValidatePayloadWithTolerance(payload []byte, header string, signingKey string, tolerance time.Duration) error {
+	return validatePayload(payload, header, signingKey, tolerance, true)
+}
+
+func validatePayload(payload []byte, sigHeader string, signingKey string, tolerance time.Duration, enforceTolerance bool) error {
+	header, err := parseSignatureHeader(sigHeader)
+	if err != nil {
+		return err
+	}
+
+	expectedSignature := computeSignature(header.timestamp, payload, signingKey)
+	expiredTimestamp := time.Since(header.timestamp) > tolerance
+	if enforceTolerance && expiredTimestamp {
+		return ErrTooOld
+	}
+
+	for _, sig := range header.signatures {
+		if hmac.Equal(expectedSignature, sig) {
+			return nil
+		}
+	}
+	return ErrNoValidSignature
+}
+
+type signedHeader struct {
+	timestamp  time.Time
+	signatures [][]byte
+}
+
+func parseSignatureHeader(header string) (*signedHeader, error) {
+	sh := &signedHeader{}
+	if header == "" {
+		return sh, ErrNotSigned
+	}
+
+	pairs := strings.Split(header, ",")
+	for _, pair := range pairs {
+		parts := strings.Split(pair, "=")
+		if len(parts) != 2 {
+			return sh, ErrInvalidHeader
+		}
+		switch parts[0] {
+		case signingTimestamp:
+			timestamp, err := strconv.ParseInt(parts[1], 10, 64)
+			if err != nil {
+				return sh, ErrInvalidHeader
+			}
+			sh.timestamp = time.Unix(timestamp, 0)
+
+		case signingVersion:
+			sig, err := hex.DecodeString(parts[1])
+			if err != nil {
+				continue
+			}
+			sh.signatures = append(sh.signatures, sig)
+		default:
+			continue
+		}
+	}
+
+	if len(sh.signatures) == 0 {
+		return sh, ErrNoValidSignature
+	}
+	return sh, nil
+}

proto/zitadel/resources/action/v3alpha/action_service.proto

@@ -408,6 +408,12 @@ message CreateTargetRequest {
 
 message CreateTargetResponse {
   zitadel.resources.object.v3alpha.Details details = 1;
+  // Key used to sign and check payload sent to the target.
+  string signing_key = 2 [
+    (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
+      example: "\"98KmsU67\""
+    }
+  ];
 }
 
 message PatchTargetRequest {
@@ -433,6 +439,12 @@ message PatchTargetRequest {
 
 message PatchTargetResponse {
   zitadel.resources.object.v3alpha.Details details = 1;
+  // Key used to sign and check payload sent to the target.
+  optional string signing_key = 2 [
+    (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
+      example: "\"98KmsU67\""
+    }
+  ];
 }
 
 message DeleteTargetRequest {

proto/zitadel/resources/action/v3alpha/target.proto

@@ -9,6 +9,7 @@ import "google/protobuf/struct.proto";
 import "protoc-gen-openapiv2/options/annotations.proto";
 import "validate/validate.proto";
 import "zitadel/protoc_gen_zitadel/v2/options.proto";
+import "google/protobuf/timestamp.proto";
 
 import "zitadel/resources/object/v3alpha/object.proto";
 
@@ -51,6 +52,11 @@ message Target {
 message GetTarget {
   zitadel.resources.object.v3alpha.Details details = 1;
   Target config = 2;
+  string signing_key = 3 [
+    (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
+      example: "\"98KmsU67\""
+    }
+  ];
 }
 
 message PatchTarget {
@@ -84,6 +90,21 @@ message PatchTarget {
       max_length: 1000
     }
   ];
+  // Regenerate the key used for signing and checking the payload sent to the target.
+  // Set the graceful period for the existing key. During that time, the previous
+  // signing key and the new one will be used to sign the request to allow you a smooth
+  // transition onf your API.
+  //
+  // Note that we currently only allow an immediate rotation ("0s") and will support
+  // longer expirations in the future.
+  optional google.protobuf.Duration expiration_signing_key = 7 [
+    (validate.rules).duration = {const: {seconds: 0, nanos: 0}},
+    (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_field) = {
+      example: "\"0s\""
+      minimum: 0
+      maximum: 0
+    }
+  ];
 }