Employer Identification Numbers (EIN)

Filter

This filter identifies US Employer Identification Numbers (EIN), the federal tax ID, in the canonical form NN-NNNNNNN (two digits, a hyphen, then seven digits) such as 12-3456789.

Only the hyphenated form is detected. A bare nine-digit run is ambiguous with an SSN and is not claimed as an EIN; the hyphen after the second digit is what distinguishes an EIN from an SSN (whose canonical form hyphenates after the third and fifth digits). When both the ein and ssn filters are enabled, a value in the NN-NNNNNNN form resolves to EIN.

Required Parameters

This filter has no required parameters.

Optional Parameters

Parameter	Description	Default Value
einFilterStrategies	A list of filter strategies.	None
onlyValidPrefixes	When true, only detect EINs whose two-digit prefix is one the IRS currently issues. This reduces false positives on format-valid but non-issued numbers. A prefix added by the IRS after this release is recognized only once the engine's prefix 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.	== , !=
CONTEXT	Compares the filtering context.	== , !=
CONFIDENCE	Compares the confidence in the sensitive text against a threshold value.	< , <=, > , >=, ==, !=

Example Policy

{
   "identifiers": {
      "ein": {
         "onlyValidPrefixes": true,
         "einFilterStrategies": [
            {
               "strategy": "REDACT",
               "redactionFormat": "{{{REDACTED-%t}}}"
            }
         ]
      }
   }
}

The ein filter requires redaction policy schema 1.2.0.