Crypto Extension

Prerequisites

• utag v4.38 or later. For more information about updating the utag.js template, see our knowledge base article Best Practices for Updating to the Latest Version of utag.js.
• See About Extensions to become familiar with how extension work.

How it works

A cryptographic hash function is used to convert a text value containing sensitive information into an anonymous and unique, fixed-length string of characters. For example, hashing is commonly applied to a user’s email address to anonymize the value while retaining its uniqueness. This extension offers a variety of commonly used hashing function algorithms, such as MD5 and SHA-1.

A data layer variable set in the extension is overwritten with the new hashed value. To generate a hashed value and preserve the original variable, use a second variable for the hashed value.

The term hashing is not synonomous with encryption.

Using the extension

Once the Crypto extension is added, configure the following fields:

• Hash Method
  Select one of the available hashing functions:
  • MD5
    The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value.
  • SHA-1
    The SHA-1 (Secure Hash Algorithm 1) is a hash function that takes an input and produces a 160-bit (20-byte) hash value known as a message digest – often rendered as a hexadecimal number, 40 digits long.
  • SHA256
    The SHA256 hash function generates an almost-unique 256-bit (32-byte) signature for a text. SHA256 is a variant of the SHA-2 (Secure Hash Algorithm 2) set of cryptographic hash functions.
  • SHA512
    A hash function that, when applied to the provided input, results in a 128-digit hexadecimal number that is highly unlikely to match the value produced for a different input. SHA512 is a variant of the SHA-2 (Secure Hash Algorithm 2) set of cryptographic hash functions.
  • Variable
    Click + Add Variable to add a variable value using the selected cryptographic function. Repeat this step to hash additional variables.

Example

The following example hashes a data layer variable named customer_email:

> utag_data.customer_email
< "test@tealium.com"

With the Crypto extension configured to convert customer_email using the SHA-1 cryptographic hash function, the new value becomes:

> utag_data.customer_email
< "05fcf31275aa13408ace62e84dac60ae4b805a65"

To preserve customer_email and create a hashed value, use a second variable named customer_email_hash. First, use the Set Data Values extension to initialize the hash variable customer_email_hash to the value in customer_email, and then convert it in the Crypto extension. This ensures you preserve the original value after creating the new hash value:

> utag_data.customer_email
< "test@tealium.com"
> utag_data.customer_email_hash
< "05fcf31275aa13408ace62e84dac60ae4b805a65"

Another option is to scope the Crypto extension only to the tags that use the hashed value. This preserves the original variable for all other tags.