Handlebars Reference: Encoding and Hashing Helpers

You can use Handlebars to encode or hash values in your dynamic content. This article describes the various encoding and hashing helpers Iterable supports and how to use them.

# In this article

# Hashing helpers

You can use hashing helpers to generate common hash-based message authentication codes (HMACs) that are useful for encrypting user data for security.

A great use case for this is if you want to automatically populate a web page (like your company's messaging preferences center) with a user's details when they click a link. You need to reference the user's data in order to personalize their experience, but it's best practice not to expose personal data in a URL. With these Handlebars helpers, you can reference a user's personal data while also keeping it secure.

The hashing Handlebars helpers Iterable supports are based on various Secure Hash Algorithms, which differ in terms of the levels of security they provide. The supported hashing helpers are listed in this section from most recent (and most secure) to oldest and least secure.

# Generate a SHA-256 HMAC

The hmacSHA256 helper generates a Secure Hash Algorithm 2 (SHA-2) HMAC hash for the value of the specified user or event data field using your project's HMAC secret.

Because this helper hashes the value of the specified data field using a more recent standard of the Secure Hashing Algorithm (SHA-256) and requires authentication with a secret key, it provides the highest level of security.

# Properties

fieldName — The name of the user or event data field whose value you want to encrypt.

# Format

{{hmacSHA256 fieldName}}

# Example

Code	Example userId value	Output
	123456789	10ec54aa2d39e7ba838e3c485b46436d70c5f577f3df20f8ba8c5e7559d568dc

# Generate a SHA-256 hash

The sha256 helper encrypts the value of the specified user or event data field as a SHA-256 hash.

Because this helper only hashes the value of a data field but does not require authentication with a secret key, it provides a lower level of security than the hmacSHA256 helper.

# Properties

fieldName — The name of the user or event data field whose value you want to encrypt.

# Format

Standard helper:

{{sha256 fieldName}}

Block helper:

{{#sha256}}{{fieldName}}{{/sha256}}

# Example

Code	Example email value	Output
	user@example.com	3a86c6f084291fda367f24e885c74d2f1d50419eb4028d2b1bb2060d8f45ce0b

# Generate a SHA-1 HMAC

The hmacSHA1 helper generates a Secure Hash Algorithm 1 (SHA-1) HMAC hash for the value of the specified user or event data field using your project's HMAC secret.

Because this helper hashes the value of the specified data field and requires authentication with a secret key, it provides a higher level of security than the sha1 helper. However, it uses an older (and less secure) standard of the Secure Hash Algorithm. When possible, we recommend using SHA-256.

# Properties

fieldName — The name of the user or event data field whose value you want to encrypt.

# Format

{{hmacSHA1 fieldName}}

# Example

Code	Example userId value	Output
	123456789	310cf1d869f57ad61fc46d45fc9496fa1a628162

# Generate a SHA-1 hash

The sha1 helper generates a Secure Hash Algorithm 1 (SHA-1) hash for the value of the specified user or event data field.

# Properties

fieldName — The name of the user or event data field whose value you want to encrypt.

# Format

Standard helper:

{{sha1 fieldName}}

Block helper:

{{#sha1}}{{fieldName}}{{/sha1}}

# Example

Code	Example email value	Output
	user@example.com	63a710569261a24b3766275b7000ce8d7b32e2f7

# Generate an MD5 hash

The md5 helper generates an MD5 hash.

# Properties

fieldName — The name of the user or event data field whose value you want to encrypt.

# Format

Standard helper:

{{md5 fieldName}}

Block helper:

{{#md5}}{{fieldName}}{{/md5}}

# Example

Code	Example email value	Output
	user@example.com	b58996c504c5638798eb6b511e6f49af

# Encoding helpers

You can use encoding helpers to change the representation of values in your dynamic content for use in different formats like Base64, JSON, and URLs.

# Convert a value to Base64

The #base64 helper converts a value to Base64.

# Properties

fieldName — The name of the data field whose value should be converted to Base64.

# Format

{{#base64}}{{fieldName}}{{/base64}}

# Example

Code	Example email value	Output
	user@example.com	ZG9jc0BpdGVyYWJsZS5jb20=

# Format a value as JSON

The toJson helper formats a value for use in a JSON field.

# Properties

fieldName — The name of the data field whose value should be formatted as JSON.

# Format

{{toJson fieldName}}

# Example

Code	Example drink value	Output
	piña colada	"piña colada"

# Format a value as a URL-encoded JSON string

The toUrlEncodedJson helper formats a value for use in a JSON field. Special characters like quotes (""), curly braces ({}), and square brackets ([]) are encoded as they would be for use in a URL.

# Properties

fieldName — The name of the data field whose value should be formatted as a URL-encoded JSON string.

# Format

{{toUrlEncodedJson fieldName}}

# Example

Code	Example drink value	Output
	piña colada	%22pi%C3%B1a+colada%22

# Format a value for use in a URL

The #urlEncode block helper converts a string (or the value of a data field containing a string) to standard URL formatting. Spaces are replaced with plus signs (+), and special characters (for example, ñ) are converted to their ASCII equivalent.

# Properties

fieldName — The name of the data field whose value should be formatted for use in a URL.

# Format

{{#urlEncode}}{{fieldName}}{{/urlEncode}}

# Example

Code	Example drink value	Output
	piña colada	pi%C3%B1a+colada

# Hex-encode a value

The hexEncode helper encodes the value of a user or event data field as a hexadecimal string.

# Properties

fieldName — The name of the data field whose value should be hex-encoded.

# Format

Standard helper:

{{hexEncode fieldName}}

Block helper:

{{#hexEncode}}{{fieldName}}{{/hexEncode}}

# Example

Code	Example email value	Output
	user@example.com	75736572406578616d706c652e636f6d

# Want to learn more?

For more information about some of the topics in this article, check out these resources. Iterable Academy is open to everyone — you don't need to be an Iterable customer!

Iterable Academy

• Handlebars 101
• Intermediate Handlebars
• Advanced Handlebars

Support docs

• Handlebars Overview
• Templates Overview