Preserve format method

The Preserve format masks data in accordance to format requirements and maintains the maximum data utility specific to a data class. 

For all the 165 pre-defined data classes in IBM Knowledge Catalog, Masking flow defines the data class's masking format to use for format-preserving tokenization and encryption.

There are five major data class format groups:

  • Credit card numbers, social security numbers, and national identifiers. Masking flow preserves the national and international requirements for these data classes. For example, the first three digits of social security numbers in the United States can fall in only the ranges of (001 - 665, 667-899).

  • First names, street names, and cities are masked with a default list of first names, street names, and cities that are common in the United States. For other determinate list-based data classes, such as states, countries, Masking flow has a list of all legal values.

  • Email addresses. See the Advanced data settings for data classes table.

  • Date, Date of birth, and Credit Card Expiration Dates are masked with date options. See the Advanced data settings for data classes table.

  • Identifier data classes, such as business IDs and customer IDs are recommended to be masked with the Identifier masking.

By using the Preserve format method, some data classes might have more advanced settings, in addition to Consistency and Input Validation.

Table 1. Advanced data settings for data classes
Data class Additional options Examples
Email address Username format: Select an option to mask email usernames.
Generate username: Generate username masks the username with firstname.lastname values from a default list of US first names and last names.
Prefix plus number: Prefix plus number masks the username with the user-specified prefix and a random sequential number.

Domain name: Select an option to mask the email domain name.
Original: Maintains the original domain name of the unmasked value.
Common email services: Masks the domain name with a domain name from a default list of the most common email services.
Custom: Masks the domain name with a user-specified domain name value.
Original data: brown.white@gmail.com
Masked value with the generated username and original domain name: joi.chillo@gmail.com
Masked value with the prefix plus number (user-specified prefix: 123) and common email services domain name: 1233728615@yahoo.com
Date Basic date masking
Shift date by fixed amount
Mask date to same time period:
Same week
Same month
Same quarter
Same year
Original date 2022-03-12
Mask dates using a date range from 2022-01-01 to 2022-05-31.
Mask dates by an interval of two days to 2022-03-14.
Mask preserving same week: 2022-03-09

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Parent topic: Obfuscating data method