Character Replacement framework

The character replacement framework allows creation of rules to replace specific characters in a string with other characters. The framework must wrap another string algorithm, which defaults to Alpha Numeric. Character replacement is often used as part of a chained string algorithm, either before or after masking. Other features are removal of accented characters and ensuring that output of the algorithm is changed from the input. At this time, there is no UI or default instance for the character replacement framework.

Replacement of characters is specified in a list of JSON rules. There is no enforced limit to the number of rules that can be created.

Create a Character Replacement algorithm via API

{
    "stringAlgorithm": {
        "name": "dlpx-core:CM Alpha-Numeric"    },
    "replacementRules": [
        {
            "inputFilteredCharacters": null,
            "inputReplacementCharacter": null,
            "outputFilteredCharacters": ["1","2","3","4","5","6","7","8","9","0"],
            "outputReplacementCharacter": "*",
            "filteredCharacters": ["a","e","i","o","u"],
            "replacementCharacter": "+"        }
    ],
    "requireInputChange": false,
    "filterAccents": "NONE"}

Configuration parameters

Parameter	Description
stringAlgorithm Object(Required)	This must be a valid string algorithm in the Delphix engine. The string algorithm should always be chosen, but it defaults to CM Alpha Numeric.
replacementRules List(Required)	Contains a list ofJSON objects with filter pairs of characters to replace and their replacements. For each rule object you must define a filter pair for at least one of input, output or the unqualified filteredCharacters which apply to both:
requireInputChange Boolean (Required)	Whether to ensure the input to the algorithm is different than the output. Throws an exception if set to true and the input and output match.
filterAccents Enum(Required)	The accents from characters like "é" or "ñ" can be stripped and decomposed to the root character like "e" or "n". This can be done before character replacement and chained algorithm masking, after, neither or both. Accepted values: INPUT, OUTPUT, NONE, or BOTH.

Replacement rule parameters

Each replacement rule defines one or more filter pairs, which specify the characters to filter and the replacement character.

Parameter	Description
inputFilteredCharacters (Optional)	Characters filtered from the input value before masking.
inputReplacementCharacter (Optional)	Replacement character for values in inputFilteredCharacters.
outputFilteredCharacters (Optional)	Characters filtered from the output of the chained algorithm.
outputReplacementCharacter (Optional)	Replacement character for values in outputFilteredCharacters.
filteredCharacters (Optional)	Characters filtered from both input and output values.
replacementCharacter (Optional)	Replacement character for values in filteredCharacters.

Validation

Validation is done to ensure that:

• Each list of filtered characters has a corresponding replacement character (is a complete filter pair)

• Each replacement rule has at least one filter pair

• The replacement character is not present in the filtered characters

• At least one replacement rule is defined

• The stringAlgorithm key refers to a valid chained string algorithm

Examples

Examples of output vary widely because they depend on the chained string algorithm chosen. If we keep the default chained algorithm of Alpha Numeric, it will never change punctuation marks and will allow us to create examples of punctuation filtering. Consider the following configuration:

{
  "stringAlgorithm": {
    "name": "dlpx-core:CM Alpha-Numeric"
  },
  "replacementRules": [
    {
      "filteredCharacters": ["@", "#", "$", "%", "&", "+", "?"],
      "replacementCharacter": "."
    }
  ],
  "requireInputChange": false,
  "filterAccents": "BOTH"
}

Example masked values using the same keyed Alpha Numeric algorithm:

1+2+3+4+5+6+7+8+9+0 → 0.0.0.4.8.3.7.7.7.4
1+2&3?4+5&6?7+8&9?0 → 0.0.0.4.8.3.7.7.7.4

When accent filtering is enabled:

áéíóú → bkxqw
ÂÊÎÔÛ → BKXQW

In this example configuration altering the rule to filter on input, output or both makes no difference. Changing the filter point could produce different results with an algorithm that could potentially change, add or remove punctuation marks and accented characters.

Create an algorithm using this framework

To create an algorithm using this framework, follow the steps in Create an algorithm and select Character Replacement during the Configuration step.