diff --git a/grpc_api/authorization.go b/grpc_api/authorization.go
new file mode 100644
index 0000000..bb55a5c
--- /dev/null
+++ b/grpc_api/authorization.go
@@ -0,0 +1,50 @@
+package grpc_api
+
+import (
+	"Simple-Bank/token"
+	"context"
+	"fmt"
+	"google.golang.org/grpc/metadata"
+	"strings"
+)
+
+const (
+	// authorizationHeader is the name of the header containing authorization information, including access token.
+	authorizationHeader = "authorization"
+	// authorizationTypeBearer is the type of authorization bearer token.
+	authorizationTypeBearer = "bearer"
+)
+
+// authorizeUser authorizes the user based on the access token provided in the context.
+// It extracts the access token from the authorization header and verifies it using the token maker.
+// It returns the token payload if the access token is valid, otherwise it returns an error.
+func (server *GrpcServer) authorizeUser(ctx context.Context) (*token.Payload, error) {
+	mtdt, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, fmt.Errorf("missing metadata")
+	}
+
+	values := mtdt.Get(authorizationHeader)
+	if len(values) == 0 {
+		return nil, fmt.Errorf("missing authorization header")
+	}
+
+	authHeader := values[0]
+	fields := strings.Fields(authHeader)
+	if len(fields) < 2 {
+		return nil, fmt.Errorf("invalid aithorization header format")
+	}
+
+	authType := strings.ToLower(fields[0])
+	if authType != authorizationTypeBearer {
+		return nil, fmt.Errorf("unsupported authorization type: %s", authType)
+	}
+
+	accessToken := fields[1]
+	payload, err := server.tokenMaker.VerifyToken(accessToken)
+	if err != nil {
+		return nil, fmt.Errorf("invalid access token: %s", accessToken)
+	}
+
+	return payload, nil
+}
diff --git a/grpc_api/error.go b/grpc_api/error.go
index 1688ea3..ec967e8 100644
--- a/grpc_api/error.go
+++ b/grpc_api/error.go
@@ -24,3 +24,8 @@ func invalidArgumentError(violations []*errdetails.BadRequest_FieldViolation) er
 
 	return statusDetails.Err()
 }
+
+// unAuthenticatedError creates and returns an unauthenticated gRPC error with the input error message.
+func unAuthenticatedError(err error) error {
+	return status.Errorf(codes.Unauthenticated, "unauthorized: %s", err)
+}
diff --git a/grpc_api/rpc_update_user.go b/grpc_api/rpc_update_user.go
index 135071a..bf599c4 100644
--- a/grpc_api/rpc_update_user.go
+++ b/grpc_api/rpc_update_user.go
@@ -11,12 +11,21 @@ import (
 )
 
 func (server *GrpcServer) UpdateUser(context context.Context, req *pb.UpdateUserRequest) (*pb.UpdateUserResponse, error) {
+	payload, err := server.authorizeUser(context)
+	if err != nil {
+		return nil, unAuthenticatedError(err)
+	}
+
 	violations := validateUpdateUserRequest(req)
 	if violations != nil {
 		err := invalidArgumentError(violations)
 		return nil, err
 	}
 
+	if payload.Username != req.Username {
+		return nil, status.Errorf(codes.PermissionDenied, "cannot update other users info")
+	}
+
 	updatedUser, err := server.dbServices.UpdateUser(services.UpdateUserRequest{
 		Username: req.Username,
 		Password: req.Password,