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Pass hashed emails through Cross-Device Event

Implementing the cross-device parameter within Criteo OneTag is essential for:

  • Reaching an addressable audience on Safari and Firefox today, and preparing for the third-party cookie deprecation on Chrome.

  • Enabling cross-device capabilities: if a potential customer is browsing products on your website from their mobile device, this parameter makes it possible to later show this customer relevant ads on their desktop device.

  • Improving your match rates when you upload contact lists to Commerce Growth or send via API.

How it works

The cross-device parameter is a small snippet of code that allows you to pass the hashed email addresses of visitors to your website. All email addresses will be hashed, using a SHA-256 algorithm, before being stored on Criteo's servers. Criteo will then use the hash value to match users across each of their devices.

To ensure we protect your customers’ privacy, Criteo will only store the hashed email addresses of your customers on our servers.

Do I need to update my website's privacy policy?

You need to ensure your Website Privacy Policy clearly informs your website visitors that email addresses may be collected and shared with third-parties that you collaborate with to optimize campaign performance and that this information is hashed using the latest and most secure SHA256 hashing technology.

Additionally you should inform your visitors that you respect their privacy, and should they prefer not to share such information, they can do so via selecting their preferred options in your website user cookie compliance banner (CMP).

Please refer to Criteo's Privacy Policy for more information, and you may also include the provided link within your website's Privacy Policy section. 

How to implement the cross-device parameter

To provide the most flexibility to you, Criteo accepts users' email addresses in these formats:

  • SHA256 hashed (in line with industry standards for addressable advertising).

  • MD5 or SHA256MD5 hashed (Criteo's legacy methods).

  • Plain text (we will thereafter use SHA256 encryption on the emails).

More details on each method of implementing the cross-device parameter: