JSON Data Masking is a library for .NET Core applications that simplifies the masking process of PII/sensitive information.

After installing the Nuget package in your project, you need to take the following steps:

1. Add the [SensitiveData] attribute in your class properties to indicate what should be masked, and use its available fields to configure the masking:

   • PreserveLength: Set to true to keep the property length when masking its value. By default this setting is set to false.
   • ShowFirst: If set, shows the first N characters of the property, not masking them. The default value is 0.
   • ShowLast: If set, shows the last N characters of the property, not masking them. The default value is 0.
   • SubstituteText: If set, the entire property value will be override with this text. Note that using this setting will ignore all other settings.
   • Mask: Set to a character to use it when masking the property's value. By default, the character * is used.

2. Call the JsonMask.MaskSensitiveData() function, passing in your object instance as a parameter.

This library supports masking of string fields only, although it also supports List<string>/IEnumerable<string> and Dictionary<string, string>. Nested class properties are also masked, independently of depth.

public class PropertiesExamples
{
    /// 123456789 results in "*****"
    [SensitiveData]
    public string DefaultMask { get; set; }

    /// 123456789 results in "REDACTED"
    [SensitiveData(SubstituteText = "REDACTED")]
    public string SubstituteMask { get; set; }

    /// 123456789 results in "123*****789"
    [SensitiveData(ShowFirst = 3, ShowLast = 3)]
    public string ShowCharactersMask { get; set; }

    /// 123456789 results in "#########"
    [SensitiveData(PreserveLength = true, Mask = "#")]
    public string PreserveCustomMask { get; set; }
}

var maskedData = JsonMask.MaskSensitiveData(data);

• DeepCloner