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Pattern 1: Encrypting Payment Data

This pattern selects authored payment fields for encryption, retains chosen display fields, and removes the source values. Review the retained fields and key boundary before adaptation.

The Pattern​

For any object containing a credit card number, the pattern is:

  1. Encrypt the full card_number using a strong encryption key.
  2. Extract analytics-safe fields like card_last_four and card_brand.
  3. Delete the original plaintext card_number.

Implementation​

You can apply this pattern with a single mapping processor.

  1. Start with a Foundation: Begin with a pipeline that simply passes through payment data, like the encryption-foundation.yaml from the previous tutorial.

  2. Add the Encryption Processor: Add this processor to your pipeline. It implements the complete pattern in one step.

    Add this processor to your pipeline
    - mapping: |
        # 1. ENCRYPT
        # Encrypt the full card number after cleaning it.
        let clean_card = this.payment.card_number.re_replace_all("[^0-9]", "")
        root.payment.card_number_encrypted = clean_card.encrypt_aes("gcm", env("CARD_ENCRYPTION_KEY"))

        # 2. PRESERVE
        # Extract the last 4 digits and card brand.
        root.payment.card_last_four = clean_card.slice(-4)
        root.payment.card_brand = if clean_card.has_prefix("4") { "visa" } else { "unknown" }

        # 3. DELETE
        # Remove the original plaintext field.
        root.payment = this.payment.without("card_number")

Verification​

When you run data through this pipeline, the output payment object will no longer contain the plaintext card_number. Instead, it will have the card_number_encrypted, card_last_four, and card_brand fields, satisfying both security requirements and business analytics needs. This same pattern can be applied to other sensitive payment fields like the CVV and cardholder name.