Step 2: Replace the IP address

Read the source value before deleting it, then add the derived field to the new root object.

IP mapping

- mapping: |
    root = this.without("ip_address")
    root.ip_hash = this.ip_address.hash(
      "hmac_sha256",
      env("IP_SALT")
    ).encode("hex")

A stable hash remains linkable across records. Define salt access, rotation, and retention for the actual environment, and decide whether stable linkage is required.

Next: transform the email address.