Individual Taxpayer Identification Numbers (ITIN)

Filter

This filter identifies US Individual Taxpayer Identification Numbers (ITIN). An ITIN has the same shape as an SSN but always begins with 9, such as 912-70-1234. Detected values are reported with the span type itin.

The filter accepts the same forms as the SSN filter: hyphenated (912-70-1234), separated by a single space (912 70 1234), or unformatted (912701234). The same hyphen substitutes and line-wrap handling apply, so 912- at the end of one line followed by 70-1234 on the next is detected as one ITIN.

The SSN filter never reports a value beginning with 9, so when both the itin and ssn filters are enabled an ITIN is reported only as itin and an SSN only as ssn.

Adoption Taxpayer Identification Numbers (ATIN), which have the form 9XX-93-XXXX, are reported as itin unless onlyValidRanges is true.

Required Parameters

This filter has no required parameters.

Optional Parameters

Parameter	Description	Default Value
itinFilterStrategies	A list of filter strategies.	None
onlyValidRanges	When true, only detect ITINs whose fourth and fifth digits fall in the ranges the IRS issues: 50 to 65, 70 to 88, 90 to 92, and 94 to 99 (IRS Publication 4757). This reduces false positives but drops ATINs (93) and any range the IRS adds after this release until the engine's range list is updated.	false
enabled	When set to false, the filter will be disabled and not applied	true
ignored	A list of terms to be ignored by the filter.	None
windowSize	Sets the size of the window (in terms) surrounding a span to look for contextual terms. If set, this value overrides the value of span.window.size in the configuration.	The value of span.window.size which is by default 5.
priority	The priority (integer) of this filter. Valid values are any positive integer, where a higher value indicates a higher priority. Priority is used for tie-breaking when two spans may be otherwise identical.	0

Filter Strategies

The filter may have zero or more filter strategies. When no filter strategy is given the default strategy of REDACT is used. When multiple filter strategies are given the filter strategies will be applied in order as they are listed. See Filter Strategies for details.

Strategy	Description
REDACT	Replace the sensitive text with a placeholder.
MASK	Replace each character of the sensitive text with a mask character (* by default).
TRUNCATE	Replace all but a few characters of the sensitive text with a truncation character (* by default).
RANDOM_REPLACE	Replace the sensitive text with a similar, random value.
STATIC_REPLACE	Replace the sensitive text with a given value.
CRYPTO_REPLACE	Replace the sensitive text with its encrypted value.
HASH_SHA256_REPLACE	Replace the sensitive text with its SHA256 hash value.
FPE_ENCRYPT_REPLACE	Replace the sensitive text with a value generated by format-preserving encryption (FPE)
LAST_4	Replace the sensitive text with just the last four characters of the text.

Conditions

Each filter strategy may have one condition. See Conditions for details.

Conditional	Description	Operators
TOKEN	Compares the value of the sensitive text.	==, !=, startswith
CONTEXT	Compares the filtering context.	== , !=
CONFIDENCE	Compares the confidence in the sensitive text against a threshold value.	< , <=, > , >=, ==, !=

Example Policy

{
   "identifiers": {
      "itin": {
         "onlyValidRanges": true,
         "itinFilterStrategies": [
            {
               "strategy": "LAST_4"
            }
         ]
      }
   }
}

The itin filter requires redaction policy schema 1.3.0 as bundled with PhiSQL 1.5.0 or later.