           <mat-button-toggle value="DECODE" class="toolbar-button-toggle" color="accent">
                    Decode
                    </mat-button-toggle>
                </mat-button-toggle-group>
            </mat-toolbar>
        </mat-card-header>
        <mat-card-content>

            <div class="option-row">
                <mat-form-field style="width: 75px;">
                    <input matInput type="number" [(ngModel)]="optMultkey" (ngModelChange)="handleText()" name="optMultkey" pla