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Replace the first n characters

This function masks the first n characters, while the following ones remain as is.
Option Description
Method The Randomly method randomly selects a character. As a result, two identical input values can be masked with different output values.

When the same value appears twice in the input data, the Consistently method ensures that the function outputs the same masked value in the same Job execution.

This function can encrypt the output masked values in the same format as the input values, using Format-Preserving Encryption (FPE) methods:

  • FF1 with AES relies on the Advanced Encryption Standard in CBC mode.
  • FF1 with SHA-2 relies on the secure hash function HMAC-256.

The FPE methods are bijective methods, except when using tweaks.

The FF1 with AES and FF1 with SHA-2 methods require a password to generate encrypted and repeatable masked values. Those FPE methods do not use a seed.

You can specify this password in the Password or 256-bit key for FF1 methods field, from the Advanced Settings of the component.

Extra parameter This function requires an extra parameter.

The extra parameter must be a number. This is the number of characters to be masked.

You can enter a second extra parameter, which is the replacement character.

The following table shows examples of masked values depending on the input value, the method, and the extra parameter.
Input value Method Extra parameter Example of a masked value Details
Jack Randomly "2" Pvck The first two characters from the input values are masked.

The replacement character is not defined. The first two characters are masked with random characters

S1000D Randomly "2,s" ss000D The first two characters from the input values are masked.

The first two characters are masked with the defined character.

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