Here is what it looks like. md5
is good enough for my purpose.
// Billing
add_filter( 'woe_get_order_value_billing_first_name', function ( $value, $order, $fieldname ) {
return md5( $value );
}, 10, 3);
add_filter( 'woe_get_order_value_billing_last_name', function ( $value, $order, $fieldname ) {
return md5( $value );
}, 10, 3);
add_filter( 'woe_get_order_value_billing_email', function ( $value, $order, $fieldname ) {
return md5( $value );
}, 10, 3);
// Order number
add_filter( 'woe_get_order_value_order_number', function ( $value, $order, $fieldname ) {
return md5( $value );
}, 10, 3);