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Securing Text


As you follow along with this guide, you can check the custom properties each component supports(and what those properties do) in the type documentation. ::::

Secure Forms

Let's create a form secured with LunaDefend. Here is a simple scenario where we want to tokenize a Social Security Number.

<SecureForm name="secure-form-example" onSubmit={(e) => handleFormSubmit(e)}>
onChange={(e) => setSsnToken(}
errorHandler={(e: LunaSecError) => setError(e)} // Unlike a normal input, SecureInput can create errors
<input name="normal-input-coexisting"/>
<button type="submit">Submit</button>

If you're used to React this should look familiar. Just like a normal form, we watch for changes using onChange and use the value to update state. Where possible, LunaDefend elements attempt to mimic the behavior of basic DOM elements in order to make them easy to use and interoperable with other DOM libraries.

For example, <SecureInput> calls onChange and onBlur event handlers just like the native <input> element. For the most part, they can be styled just like native elements and will allow you to build forms and pages as you normally would, with a few exceptions.

The secure input we created shouldn't change how the app looks at all (that's the point) but if we right-click and inspect it we can see the cross-domain iFrame that LunaDefend creates to protect your data. ::: Creating a Text Area for multi-line data entry is pretty similar, this time let's give it some custom styling:

// ... inside secure form
style={{ height: '45px' }}
// token={some.prefilled.value}
onChange={(e) => setTextAreaToken(}
errorHandler={(e) => setError(e.message)}

<SecureInput> and <SecureTextArea> need to be inside a <SecureForm> because it captures submit events and tells them to tokenize their plaintext. <SecureForm> will wait to fire your onSubmit handler until they are done tokenizing. Note that normal submit methods like a submit button or hitting enter in a text box work normally.

Displaying Secure Data

The <SecureParagraph> element can take a token and display it as text.

errorHandler={(e) => setError(e.message)}

The major caveat here is that the text can't be displayed inline because we don't want to leak any information about the length of the secured data to the surrounding page. It's a good idea to style this element large enough to display the text it's going to hold.

Advanced Usage

Now that we've seen a how simple it can be, let's look at a more advanced use case. SecureInput supports many options and can be used with component libraries.

Here is a more complex example of the props that <SecureInput> can take:

// Normal input properties
onChange={(e) => setSsnToken(}
// Special LunaDefend properties
onValidate={(isValid) => setSsnValid(isValid)}
errorHandler={(e) => setError(e.message)}

Inputs come with support for all the normal input types such as email and password. They are able to take a token for prefilling the field with some previously created secure data. You can choose from one of several pre-made validators if you need basic validation.

Special Cases

Some things you would normally do may need to be done differently or may not be possible because your page just doesn't have access to the plaintext value. An example of this is validations, where you have to use one of our pre-made validators.

Please contact us if you have a use case that this library doesn't support. We are exploring the possibility of running custom plugins in the Secure Frame.

Component Library Interoperability

LunaDefend can work with component libraries that allow passing of a custom element, like MaterialUI. Here is an example from the Demo App of using <SecureInput> inside of a MaterialUI <TextField>.

import { SecureForm, SecureInput } from '@lunasec/react-sdk';
import { TextField } from '@material-ui/core';

// These props are predefined like this to preserve the strong typing.
// We are being fancy here and passing these into MaterialUi
const secureInputProps: React.ComponentProps<typeof SecureInput> = {
id: 'ssn-token-input',
name: 'ssn',
type: 'ssn',
validator: 'SSN',
onValidate: (isValid: boolean) => setSsnValid(isValid),
token: user.ssn_token || undefined,
placeholder: 'XXX-XX-XXXX',
onChange: (e) => setSsnToken(,
errorHandler: (e) => setError(e.message),

// ...inside a secure form
<TextField // This is a material UI component
helperText={ssnValid ? '' : 'Invalid Format'}
// label="Labels don't work quite right yet"
// @ts-ignore */
inputComponent: SecureInput, // Pass in our secure input
inputProps: secureInputProps, // Pass in the properties to it

This type of usage is experimental and not every feature is guaranteed to be perfectly supported. That said, the results are impressive given that the actual element is running inside an iFrame on another domain. It's likely good enough for most applications, even where UX is important. To see it running, try using the SecureInput in the Demo App.

LunaDefend should also work just fine with a form library like Formik.

Next let's handle some secure files.