diff --git a/Makefile b/Makefile
index 6fff585c6..b0b295637 100644
--- a/Makefile
+++ b/Makefile
@@ -66,7 +66,7 @@ protoc:
 	@for f in `find . -type f -name '*.proto' -not -path './vendor/*'`; do \
 		echo "⇒ Processing $$f "; \
 		protoc \
-			--proto_path=.:./vendor:./vendor/github.com/nspcc-dev/neofs-api-go:/usr/local/include \
+			--proto_path=.:./vendor:./vendor/github.com/nspcc-dev/neofs-api-go:/usr/local/include:./pkg/services/private \
 			--gofast_out=plugins=grpc,paths=source_relative:. $$f; \
 	done
 	rm -rf vendor
diff --git a/go.mod b/go.mod
index f0501e418..8a3223713 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,7 @@ go 1.14
 require (
 	code.cloudfoundry.org/bytefmt v0.0.0-20200131002437-cf55d5288a48
 	github.com/alecthomas/participle v0.6.0
+	github.com/golang/protobuf v1.4.3
 	github.com/google/uuid v1.1.1
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/klauspost/compress v1.11.3
diff --git a/go.sum b/go.sum
index 29b9824fb..402a5840d 100644
--- a/go.sum
+++ b/go.sum
@@ -120,6 +120,7 @@ github.com/go-redis/redis v6.10.2+incompatible/go.mod h1:NAIEuMOZ/fxfXJIrKDQDz8w
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-yaml/yaml v2.1.0+incompatible/go.mod h1:w2MrLa16VYP0jy6N7M5kHaCkaLENm+P+Tv+MfurjSw0=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
+github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190129154638-5b532d6fd5ef/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
diff --git a/pkg/services/private/service.pb.go b/pkg/services/private/service.pb.go
new file mode 100644
index 000000000..3c12c3fb7
--- /dev/null
+++ b/pkg/services/private/service.pb.go
@@ -0,0 +1,1043 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: pkg/services/private/service.proto
+
+package private
+
+import (
+	context "context"
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	grpc "google.golang.org/grpc"
+	io "io"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+// Health check request.
+type HealthCheckRequest struct {
+	// Body of health check request message.
+	Body *HealthCheckRequest_Body `protobuf:"bytes,1,opt,name=body,proto3" json:"body,omitempty"`
+	// Body signature.
+	Signature            *Signature `protobuf:"bytes,2,opt,name=signature,proto3" json:"signature,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}   `json:"-"`
+	XXX_unrecognized     []byte     `json:"-"`
+	XXX_sizecache        int32      `json:"-"`
+}
+
+func (m *HealthCheckRequest) Reset()         { *m = HealthCheckRequest{} }
+func (m *HealthCheckRequest) String() string { return proto.CompactTextString(m) }
+func (*HealthCheckRequest) ProtoMessage()    {}
+func (*HealthCheckRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_730cfa0cfa54ede8, []int{0}
+}
+func (m *HealthCheckRequest) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *HealthCheckRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_HealthCheckRequest.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *HealthCheckRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_HealthCheckRequest.Merge(m, src)
+}
+func (m *HealthCheckRequest) XXX_Size() int {
+	return m.Size()
+}
+func (m *HealthCheckRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_HealthCheckRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_HealthCheckRequest proto.InternalMessageInfo
+
+func (m *HealthCheckRequest) GetBody() *HealthCheckRequest_Body {
+	if m != nil {
+		return m.Body
+	}
+	return nil
+}
+
+func (m *HealthCheckRequest) GetSignature() *Signature {
+	if m != nil {
+		return m.Signature
+	}
+	return nil
+}
+
+// Health check request body.
+type HealthCheckRequest_Body struct {
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *HealthCheckRequest_Body) Reset()         { *m = HealthCheckRequest_Body{} }
+func (m *HealthCheckRequest_Body) String() string { return proto.CompactTextString(m) }
+func (*HealthCheckRequest_Body) ProtoMessage()    {}
+func (*HealthCheckRequest_Body) Descriptor() ([]byte, []int) {
+	return fileDescriptor_730cfa0cfa54ede8, []int{0, 0}
+}
+func (m *HealthCheckRequest_Body) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *HealthCheckRequest_Body) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_HealthCheckRequest_Body.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *HealthCheckRequest_Body) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_HealthCheckRequest_Body.Merge(m, src)
+}
+func (m *HealthCheckRequest_Body) XXX_Size() int {
+	return m.Size()
+}
+func (m *HealthCheckRequest_Body) XXX_DiscardUnknown() {
+	xxx_messageInfo_HealthCheckRequest_Body.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_HealthCheckRequest_Body proto.InternalMessageInfo
+
+// Health check request.
+type HealthCheckResponse struct {
+	// Body of health check response message.
+	Body *HealthCheckResponse_Body `protobuf:"bytes,1,opt,name=body,proto3" json:"body,omitempty"`
+	// Body signature.
+	Signature            *Signature `protobuf:"bytes,2,opt,name=signature,proto3" json:"signature,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}   `json:"-"`
+	XXX_unrecognized     []byte     `json:"-"`
+	XXX_sizecache        int32      `json:"-"`
+}
+
+func (m *HealthCheckResponse) Reset()         { *m = HealthCheckResponse{} }
+func (m *HealthCheckResponse) String() string { return proto.CompactTextString(m) }
+func (*HealthCheckResponse) ProtoMessage()    {}
+func (*HealthCheckResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_730cfa0cfa54ede8, []int{1}
+}
+func (m *HealthCheckResponse) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *HealthCheckResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_HealthCheckResponse.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *HealthCheckResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_HealthCheckResponse.Merge(m, src)
+}
+func (m *HealthCheckResponse) XXX_Size() int {
+	return m.Size()
+}
+func (m *HealthCheckResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_HealthCheckResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_HealthCheckResponse proto.InternalMessageInfo
+
+func (m *HealthCheckResponse) GetBody() *HealthCheckResponse_Body {
+	if m != nil {
+		return m.Body
+	}
+	return nil
+}
+
+func (m *HealthCheckResponse) GetSignature() *Signature {
+	if m != nil {
+		return m.Signature
+	}
+	return nil
+}
+
+// Health check response body
+type HealthCheckResponse_Body struct {
+	// Health status of storage node.
+	Status               HealthStatus `protobuf:"varint,1,opt,name=status,proto3,enum=private.HealthStatus" json:"status,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}     `json:"-"`
+	XXX_unrecognized     []byte       `json:"-"`
+	XXX_sizecache        int32        `json:"-"`
+}
+
+func (m *HealthCheckResponse_Body) Reset()         { *m = HealthCheckResponse_Body{} }
+func (m *HealthCheckResponse_Body) String() string { return proto.CompactTextString(m) }
+func (*HealthCheckResponse_Body) ProtoMessage()    {}
+func (*HealthCheckResponse_Body) Descriptor() ([]byte, []int) {
+	return fileDescriptor_730cfa0cfa54ede8, []int{1, 0}
+}
+func (m *HealthCheckResponse_Body) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *HealthCheckResponse_Body) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_HealthCheckResponse_Body.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *HealthCheckResponse_Body) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_HealthCheckResponse_Body.Merge(m, src)
+}
+func (m *HealthCheckResponse_Body) XXX_Size() int {
+	return m.Size()
+}
+func (m *HealthCheckResponse_Body) XXX_DiscardUnknown() {
+	xxx_messageInfo_HealthCheckResponse_Body.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_HealthCheckResponse_Body proto.InternalMessageInfo
+
+func (m *HealthCheckResponse_Body) GetStatus() HealthStatus {
+	if m != nil {
+		return m.Status
+	}
+	return HealthStatus_STATUS_UNDEFINED
+}
+
+func init() {
+	proto.RegisterType((*HealthCheckRequest)(nil), "private.HealthCheckRequest")
+	proto.RegisterType((*HealthCheckRequest_Body)(nil), "private.HealthCheckRequest.Body")
+	proto.RegisterType((*HealthCheckResponse)(nil), "private.HealthCheckResponse")
+	proto.RegisterType((*HealthCheckResponse_Body)(nil), "private.HealthCheckResponse.Body")
+}
+
+func init() { proto.RegisterFile("pkg/services/private/service.proto", fileDescriptor_730cfa0cfa54ede8) }
+
+var fileDescriptor_730cfa0cfa54ede8 = []byte{
+	// 291 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x52, 0x2a, 0xc8, 0x4e, 0xd7,
+	0x2f, 0x4e, 0x2d, 0x2a, 0xcb, 0x4c, 0x4e, 0x2d, 0xd6, 0x2f, 0x28, 0xca, 0x2c, 0x4b, 0x2c, 0x49,
+	0x85, 0x09, 0xe8, 0x15, 0x14, 0xe5, 0x97, 0xe4, 0x0b, 0xb1, 0x43, 0x85, 0xa5, 0xb8, 0x4b, 0x2a,
+	0x0b, 0x52, 0x8b, 0x21, 0xa2, 0x4a, 0x2d, 0x8c, 0x5c, 0x42, 0x1e, 0xa9, 0x89, 0x39, 0x25, 0x19,
+	0xce, 0x19, 0xa9, 0xc9, 0xd9, 0x41, 0xa9, 0x85, 0xa5, 0xa9, 0xc5, 0x25, 0x42, 0x26, 0x5c, 0x2c,
+	0x49, 0xf9, 0x29, 0x95, 0x12, 0x8c, 0x0a, 0x8c, 0x1a, 0xdc, 0x46, 0x0a, 0x7a, 0x50, 0xbd, 0x7a,
+	0x98, 0x4a, 0xf5, 0x9c, 0xf2, 0x53, 0x2a, 0x83, 0xc0, 0xaa, 0x85, 0x0c, 0xb8, 0x38, 0x8b, 0x33,
+	0xd3, 0xf3, 0x12, 0x4b, 0x4a, 0x8b, 0x52, 0x25, 0x98, 0xc0, 0x5a, 0x85, 0xe0, 0x5a, 0x83, 0x61,
+	0x32, 0x41, 0x08, 0x45, 0x52, 0x6c, 0x5c, 0x2c, 0x20, 0xfd, 0x4a, 0x5b, 0x19, 0xb9, 0x84, 0x51,
+	0xcc, 0x2e, 0x2e, 0xc8, 0xcf, 0x2b, 0x4e, 0x15, 0x32, 0x45, 0x71, 0x87, 0x22, 0x76, 0x77, 0x40,
+	0xd4, 0x52, 0xe6, 0x10, 0x53, 0x88, 0x43, 0x84, 0x74, 0xb9, 0xd8, 0x8a, 0x4b, 0x12, 0x4b, 0x4a,
+	0x8b, 0xc1, 0x56, 0xf2, 0x19, 0x89, 0xa2, 0x59, 0x19, 0x0c, 0x96, 0x0c, 0x82, 0x2a, 0x32, 0x8a,
+	0xe2, 0xe2, 0x0b, 0x80, 0xc8, 0x07, 0x43, 0x02, 0x5b, 0xc8, 0x83, 0x8b, 0x1b, 0xc9, 0x71, 0x42,
+	0xd2, 0x78, 0x82, 0x4e, 0x4a, 0x06, 0x9f, 0x7f, 0x9c, 0xdc, 0x4e, 0x3c, 0x92, 0x63, 0xbc, 0xf0,
+	0x48, 0x8e, 0xf1, 0xc1, 0x23, 0x39, 0xc6, 0x19, 0x8f, 0xe5, 0x18, 0xa2, 0x4c, 0xd2, 0x33, 0x4b,
+	0x32, 0x4a, 0x93, 0xf4, 0x92, 0xf3, 0x73, 0xf5, 0xf3, 0x8a, 0x0b, 0x92, 0x93, 0x75, 0x53, 0x52,
+	0xcb, 0xf4, 0xf3, 0x52, 0xf3, 0xd3, 0x8a, 0x75, 0xf3, 0xf2, 0x53, 0x52, 0xf5, 0xb1, 0x25, 0x83,
+	0x24, 0x36, 0x70, 0x4c, 0x1b, 0x03, 0x02, 0x00, 0x00, 0xff, 0xff, 0xae, 0x15, 0xa0, 0xdd, 0x25,
+	0x02, 0x00, 0x00,
+}
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+const _ = grpc.SupportPackageIsVersion4
+
+// PrivateServiceClient is the client API for PrivateService service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
+type PrivateServiceClient interface {
+	// Performs health check of the storage node.
+	HealthCheck(ctx context.Context, in *HealthCheckRequest, opts ...grpc.CallOption) (*HealthCheckResponse, error)
+}
+
+type privateServiceClient struct {
+	cc *grpc.ClientConn
+}
+
+func NewPrivateServiceClient(cc *grpc.ClientConn) PrivateServiceClient {
+	return &privateServiceClient{cc}
+}
+
+func (c *privateServiceClient) HealthCheck(ctx context.Context, in *HealthCheckRequest, opts ...grpc.CallOption) (*HealthCheckResponse, error) {
+	out := new(HealthCheckResponse)
+	err := c.cc.Invoke(ctx, "/private.PrivateService/HealthCheck", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// PrivateServiceServer is the server API for PrivateService service.
+type PrivateServiceServer interface {
+	// Performs health check of the storage node.
+	HealthCheck(context.Context, *HealthCheckRequest) (*HealthCheckResponse, error)
+}
+
+func RegisterPrivateServiceServer(s *grpc.Server, srv PrivateServiceServer) {
+	s.RegisterService(&_PrivateService_serviceDesc, srv)
+}
+
+func _PrivateService_HealthCheck_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(HealthCheckRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(PrivateServiceServer).HealthCheck(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/private.PrivateService/HealthCheck",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(PrivateServiceServer).HealthCheck(ctx, req.(*HealthCheckRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+var _PrivateService_serviceDesc = grpc.ServiceDesc{
+	ServiceName: "private.PrivateService",
+	HandlerType: (*PrivateServiceServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "HealthCheck",
+			Handler:    _PrivateService_HealthCheck_Handler,
+		},
+	},
+	Streams:  []grpc.StreamDesc{},
+	Metadata: "pkg/services/private/service.proto",
+}
+
+func (m *HealthCheckRequest) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *HealthCheckRequest) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.Body != nil {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintService(dAtA, i, uint64(m.Body.Size()))
+		n1, err := m.Body.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n1
+	}
+	if m.Signature != nil {
+		dAtA[i] = 0x12
+		i++
+		i = encodeVarintService(dAtA, i, uint64(m.Signature.Size()))
+		n2, err := m.Signature.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n2
+	}
+	if m.XXX_unrecognized != nil {
+		i += copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	return i, nil
+}
+
+func (m *HealthCheckRequest_Body) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *HealthCheckRequest_Body) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		i += copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	return i, nil
+}
+
+func (m *HealthCheckResponse) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *HealthCheckResponse) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.Body != nil {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintService(dAtA, i, uint64(m.Body.Size()))
+		n3, err := m.Body.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n3
+	}
+	if m.Signature != nil {
+		dAtA[i] = 0x12
+		i++
+		i = encodeVarintService(dAtA, i, uint64(m.Signature.Size()))
+		n4, err := m.Signature.MarshalTo(dAtA[i:])
+		if err != nil {
+			return 0, err
+		}
+		i += n4
+	}
+	if m.XXX_unrecognized != nil {
+		i += copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	return i, nil
+}
+
+func (m *HealthCheckResponse_Body) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *HealthCheckResponse_Body) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if m.Status != 0 {
+		dAtA[i] = 0x8
+		i++
+		i = encodeVarintService(dAtA, i, uint64(m.Status))
+	}
+	if m.XXX_unrecognized != nil {
+		i += copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	return i, nil
+}
+
+func encodeVarintService(dAtA []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return offset + 1
+}
+func (m *HealthCheckRequest) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Body != nil {
+		l = m.Body.Size()
+		n += 1 + l + sovService(uint64(l))
+	}
+	if m.Signature != nil {
+		l = m.Signature.Size()
+		n += 1 + l + sovService(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *HealthCheckRequest_Body) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *HealthCheckResponse) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Body != nil {
+		l = m.Body.Size()
+		n += 1 + l + sovService(uint64(l))
+	}
+	if m.Signature != nil {
+		l = m.Signature.Size()
+		n += 1 + l + sovService(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func (m *HealthCheckResponse_Body) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.Status != 0 {
+		n += 1 + sovService(uint64(m.Status))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovService(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozService(x uint64) (n int) {
+	return sovService(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *HealthCheckRequest) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowService
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: HealthCheckRequest: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: HealthCheckRequest: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Body", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthService
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthService
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Body == nil {
+				m.Body = &HealthCheckRequest_Body{}
+			}
+			if err := m.Body.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Signature", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthService
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthService
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Signature == nil {
+				m.Signature = &Signature{}
+			}
+			if err := m.Signature.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipService(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *HealthCheckRequest_Body) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowService
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Body: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Body: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		default:
+			iNdEx = preIndex
+			skippy, err := skipService(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *HealthCheckResponse) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowService
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: HealthCheckResponse: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: HealthCheckResponse: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Body", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthService
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthService
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Body == nil {
+				m.Body = &HealthCheckResponse_Body{}
+			}
+			if err := m.Body.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Signature", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthService
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return ErrInvalidLengthService
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			if m.Signature == nil {
+				m.Signature = &Signature{}
+			}
+			if err := m.Signature.Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipService(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *HealthCheckResponse_Body) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowService
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Body: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Body: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Status", wireType)
+			}
+			m.Status = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Status |= HealthStatus(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipService(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthService
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipService(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowService
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowService
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthService
+			}
+			iNdEx += length
+			if iNdEx < 0 {
+				return 0, ErrInvalidLengthService
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return 0, ErrIntOverflowService
+					}
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipService(dAtA[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+				if iNdEx < 0 {
+					return 0, ErrInvalidLengthService
+				}
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthService = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowService   = fmt.Errorf("proto: integer overflow")
+)
diff --git a/pkg/services/private/service.proto b/pkg/services/private/service.proto
new file mode 100644
index 000000000..23a569fac
--- /dev/null
+++ b/pkg/services/private/service.proto
@@ -0,0 +1,41 @@
+syntax = "proto3";
+
+package private;
+
+import "types.proto";
+
+option go_package = "github.com/nspcc-dev/neofs-node/pkg/services/private";
+
+// `PrivateService` provides an interface for internal work with the storage node.
+service PrivateService {
+    // Performs health check of the storage node.
+    rpc HealthCheck (HealthCheckRequest) returns (HealthCheckResponse);
+}
+
+// Health check request.
+message HealthCheckRequest {
+    // Health check request body.
+    message Body {
+    }
+
+    // Body of health check request message.
+    Body body = 1;
+
+    // Body signature.
+    Signature signature = 2;
+}
+
+// Health check request.
+message HealthCheckResponse {
+    // Health check response body
+    message Body {
+        // Health status of storage node.
+        HealthStatus status = 1;
+    }
+
+    // Body of health check response message.
+    Body body = 1;
+
+    // Body signature.
+    Signature signature = 2;
+}
diff --git a/pkg/services/private/types.pb.go b/pkg/services/private/types.pb.go
new file mode 100644
index 000000000..373446f17
--- /dev/null
+++ b/pkg/services/private/types.pb.go
@@ -0,0 +1,446 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: pkg/services/private/types.proto
+
+package private
+
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	io "io"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+// Health status of the storage node.
+type HealthStatus int32
+
+const (
+	// Undefined status, default value.
+	HealthStatus_STATUS_UNDEFINED HealthStatus = 0
+	// Node is online.
+	HealthStatus_ONLINE HealthStatus = 1
+	// Node is offline.
+	HealthStatus_OFFLINE HealthStatus = 2
+)
+
+var HealthStatus_name = map[int32]string{
+	0: "STATUS_UNDEFINED",
+	1: "ONLINE",
+	2: "OFFLINE",
+}
+
+var HealthStatus_value = map[string]int32{
+	"STATUS_UNDEFINED": 0,
+	"ONLINE":           1,
+	"OFFLINE":          2,
+}
+
+func (x HealthStatus) String() string {
+	return proto.EnumName(HealthStatus_name, int32(x))
+}
+
+func (HealthStatus) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_d50f4a50d05f699c, []int{0}
+}
+
+// Signature of some message.
+type Signature struct {
+	// Public key used for signing.
+	Key []byte `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
+	// Binary signature.
+	Sign                 []byte   `protobuf:"bytes,2,opt,name=sign,json=signature,proto3" json:"sign,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *Signature) Reset()         { *m = Signature{} }
+func (m *Signature) String() string { return proto.CompactTextString(m) }
+func (*Signature) ProtoMessage()    {}
+func (*Signature) Descriptor() ([]byte, []int) {
+	return fileDescriptor_d50f4a50d05f699c, []int{0}
+}
+func (m *Signature) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *Signature) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_Signature.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (m *Signature) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Signature.Merge(m, src)
+}
+func (m *Signature) XXX_Size() int {
+	return m.Size()
+}
+func (m *Signature) XXX_DiscardUnknown() {
+	xxx_messageInfo_Signature.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Signature proto.InternalMessageInfo
+
+func (m *Signature) GetKey() []byte {
+	if m != nil {
+		return m.Key
+	}
+	return nil
+}
+
+func (m *Signature) GetSign() []byte {
+	if m != nil {
+		return m.Sign
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterEnum("private.HealthStatus", HealthStatus_name, HealthStatus_value)
+	proto.RegisterType((*Signature)(nil), "private.Signature")
+}
+
+func init() { proto.RegisterFile("pkg/services/private/types.proto", fileDescriptor_d50f4a50d05f699c) }
+
+var fileDescriptor_d50f4a50d05f699c = []byte{
+	// 227 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x52, 0x28, 0xc8, 0x4e, 0xd7,
+	0x2f, 0x4e, 0x2d, 0x2a, 0xcb, 0x4c, 0x4e, 0x2d, 0xd6, 0x2f, 0x28, 0xca, 0x2c, 0x4b, 0x2c, 0x49,
+	0xd5, 0x2f, 0xa9, 0x2c, 0x48, 0x2d, 0xd6, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0x62, 0x87, 0x0a,
+	0x2a, 0x99, 0x71, 0x71, 0x06, 0x67, 0xa6, 0xe7, 0x25, 0x96, 0x94, 0x16, 0xa5, 0x0a, 0x09, 0x70,
+	0x31, 0x67, 0xa7, 0x56, 0x4a, 0x30, 0x2a, 0x30, 0x6a, 0xf0, 0x04, 0x81, 0x98, 0x42, 0xe2, 0x5c,
+	0x2c, 0xc5, 0x99, 0xe9, 0x79, 0x12, 0x4c, 0x60, 0x21, 0xce, 0x62, 0x98, 0x52, 0x2d, 0x5b, 0x2e,
+	0x1e, 0x8f, 0xd4, 0xc4, 0x9c, 0x92, 0x8c, 0xe0, 0x92, 0xc4, 0x92, 0xd2, 0x62, 0x21, 0x11, 0x2e,
+	0x81, 0xe0, 0x10, 0xc7, 0x90, 0xd0, 0xe0, 0xf8, 0x50, 0x3f, 0x17, 0x57, 0x37, 0x4f, 0x3f, 0x57,
+	0x17, 0x01, 0x06, 0x21, 0x2e, 0x2e, 0x36, 0x7f, 0x3f, 0x1f, 0x4f, 0x3f, 0x57, 0x01, 0x46, 0x21,
+	0x6e, 0x2e, 0x76, 0x7f, 0x37, 0x37, 0x30, 0x87, 0xc9, 0xc9, 0xed, 0xc4, 0x23, 0x39, 0xc6, 0x0b,
+	0x8f, 0xe4, 0x18, 0x1f, 0x3c, 0x92, 0x63, 0x9c, 0xf1, 0x58, 0x8e, 0x21, 0xca, 0x24, 0x3d, 0xb3,
+	0x24, 0xa3, 0x34, 0x49, 0x2f, 0x39, 0x3f, 0x57, 0x3f, 0xaf, 0xb8, 0x20, 0x39, 0x59, 0x37, 0x25,
+	0xb5, 0x4c, 0x3f, 0x2f, 0x35, 0x3f, 0xad, 0x58, 0x37, 0x2f, 0x3f, 0x25, 0x55, 0x1f, 0x9b, 0x9f,
+	0x92, 0xd8, 0xc0, 0xde, 0x31, 0x06, 0x04, 0x00, 0x00, 0xff, 0xff, 0x57, 0x15, 0x0c, 0xc5, 0xf2,
+	0x00, 0x00, 0x00,
+}
+
+func (m *Signature) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Signature) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if len(m.Key) > 0 {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintTypes(dAtA, i, uint64(len(m.Key)))
+		i += copy(dAtA[i:], m.Key)
+	}
+	if len(m.Sign) > 0 {
+		dAtA[i] = 0x12
+		i++
+		i = encodeVarintTypes(dAtA, i, uint64(len(m.Sign)))
+		i += copy(dAtA[i:], m.Sign)
+	}
+	if m.XXX_unrecognized != nil {
+		i += copy(dAtA[i:], m.XXX_unrecognized)
+	}
+	return i, nil
+}
+
+func encodeVarintTypes(dAtA []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return offset + 1
+}
+func (m *Signature) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Key)
+	if l > 0 {
+		n += 1 + l + sovTypes(uint64(l))
+	}
+	l = len(m.Sign)
+	if l > 0 {
+		n += 1 + l + sovTypes(uint64(l))
+	}
+	if m.XXX_unrecognized != nil {
+		n += len(m.XXX_unrecognized)
+	}
+	return n
+}
+
+func sovTypes(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozTypes(x uint64) (n int) {
+	return sovTypes(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *Signature) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowTypes
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Signature: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Signature: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Key", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowTypes
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthTypes
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthTypes
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Key = append(m.Key[:0], dAtA[iNdEx:postIndex]...)
+			if m.Key == nil {
+				m.Key = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Sign", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowTypes
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return ErrInvalidLengthTypes
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return ErrInvalidLengthTypes
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Sign = append(m.Sign[:0], dAtA[iNdEx:postIndex]...)
+			if m.Sign == nil {
+				m.Sign = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := skipTypes(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthTypes
+			}
+			if (iNdEx + skippy) < 0 {
+				return ErrInvalidLengthTypes
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.XXX_unrecognized = append(m.XXX_unrecognized, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipTypes(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowTypes
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowTypes
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowTypes
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if length < 0 {
+				return 0, ErrInvalidLengthTypes
+			}
+			iNdEx += length
+			if iNdEx < 0 {
+				return 0, ErrInvalidLengthTypes
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return 0, ErrIntOverflowTypes
+					}
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipTypes(dAtA[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+				if iNdEx < 0 {
+					return 0, ErrInvalidLengthTypes
+				}
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthTypes = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowTypes   = fmt.Errorf("proto: integer overflow")
+)
diff --git a/pkg/services/private/types.proto b/pkg/services/private/types.proto
new file mode 100644
index 000000000..f473bb7ce
--- /dev/null
+++ b/pkg/services/private/types.proto
@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+package private;
+
+option go_package = "github.com/nspcc-dev/neofs-node/pkg/services/private";
+
+// Signature of some message.
+message Signature {
+    // Public key used for signing.
+    bytes key = 1 [json_name = "key"];
+
+    // Binary signature.
+    bytes sign = 2 [json_name = "signature"];
+}
+
+// Health status of the storage node.
+enum HealthStatus {
+    // Undefined status, default value.
+    STATUS_UNDEFINED = 0;
+
+    // Node is online.
+    ONLINE = 1;
+
+    // Node is offline.
+    OFFLINE = 2;
+}