Standard

How we keep people out of the data we value and bring to buyers.

Records are de-identified on the holder's own computer before anything reaches us. What is left is measured against thresholds set in advance, read by a person, and, before any buyer receives it, tested and certified by an independent provider. Every rule below cites the law, standard or study it rests on, and the engine is measured in public.

The engine

Measured, not claimed.

On the Text Anonymization Benchmark (TAB), court judgments in which legal annotators marked every identifier, with the benchmark's own strict measure: a person counts as protected only if every mention of them is masked. These figures are for the 127 judgments we did not look at while building the rules, with no list of people to help (company exports give the engine one).

93.4%

of direct identifiers (people's names and case numbers) masked in every mention: 1,080 of 1,156

88.3%

of the text it masked was text the annotators said must be masked

0.46

Microsoft Presidio on the same measure, and 0.94 for a neural tagger, as the benchmark's authors measured them on its test set

The engine leaves dates and places in place by default, which the benchmark counts as quasi-identifiers (88.4% of the other people named in the judgments are also masked); those are handled by the table checks, the review and your own lists rather than masked wholesale. Engine version 2026-10-16.4, measured 2026-10-16. The benchmark and its paper: the corpus (MIT licence) and Pilán et al. 2022.

On company records: Slack, email and shared documents

Court judgments are not what companies sell. PrivacyBench v2.5, published by Tonic.ai, is: a month of Slack, email and Drive exports from 21 invented companies, every identifier in them marked. These figures are for the 6 exports that people annotated by hand (5,198 messages and 656 document pages), which we never read while writing the rules, scored by the benchmark's own scorer beside every engine its authors published.

86.8%

F1 over all ten kinds of identifier, the measure the benchmark ranks engines by

95.8%

of the identifiers of people (names, emails, usernames, phones, addresses, ids, links) found

  • Textual Graph Synthesis
    Precision
    90.9%
    Recall
    94.3%
    F1
    92.5%
  • Textual via SDK
    Precision
    91.3%
    Recall
    92.9%
    F1
    92.1%
  • Claude Opus 5
    Precision
    92.1%
    Recall
    84.9%
    F1
    88.3%
  • Claude Sonnet 5
    Precision
    92.1%
    Recall
    82.4%
    F1
    87.0%
  • GPT-6 astra
    Precision
    88.6%
    Recall
    85.0%
    F1
    86.8%
  • AIData.Broker engine
    Precision
    88.1%
    Recall
    85.6%
    F1
    86.8%
  • GPT-5.6 sol
    Precision
    90.2%
    Recall
    82.3%
    F1
    86.1%
  • GPT-5.6 terra
    Precision
    92.4%
    Recall
    78.4%
    F1
    84.8%
  • Presidio
    Precision
    79.0%
    Recall
    87.1%
    F1
    82.8%
  • GLiNER2
    Precision
    83.7%
    Recall
    68.0%
    F1
    75.1%
  • First names
    Marked
    10,034
    Found
    94.7%
  • Surnames
    Marked
    5,204
    Found
    96.6%
  • Email addresses
    Marked
    2,453
    Found
    99.7%
  • Usernames and Slack ids
    Marked
    451
    Found
    99.3%
  • Phone numbers
    Marked
    1,036
    Found
    100.0%
  • Street addresses
    Marked
    419
    Found
    87.4%
  • Employee ids
    Marked
    295
    Found
    97.3%
  • Account numbers
    Marked
    167
    Found
    68.3%
  • Links
    Marked
    21
    Found
    61.9%
  • Organisations' names
    Marked
    5,775
    Found
    49.9%

Where it is weakest: organisations' names written as brands or departments, account numbers with no word beside them, and internal links. Those are what the AI reading every sample and the independent test before delivery are for, and what the engine is being improved on next. The benchmark's authors build the engine at the top of the table and say so on the card; the data is invented, so it holds no real person. Engine version 2026-10-18.1, measured 2026-10-18 on the card's revision of 2026-10-15: the benchmark (CC BY 4.0) and its scorer.

Where data goes

What leaves whose hands, at each stage.

The less that leaves the holder, the less there is to remove. Each stage has its own bar.

  1. The valuation

    What leaves: Counts: how many records, months, authors, links and identifiers by kind, the file types, the few mailbox domains and e-invoice company names that show whose records they are, and one-way hashes of file names and sizes. No text and no names of people.Who does what: Your browser reads your exports; authors are counted through a one-way hash that stays in your browser.The bar: Nothing personal leaves your computer, so nothing needs removing.

  2. A sample for the valuation

    What leaves: A small part of your records, rewritten on your computer by the de-identification engine, with its report of counts.Who does what: You run the engine and read records picked at random; our server checks the text again on arrival, measures it and deletes it at once.The bar: Every identifier replaced, a second check finds none, a person read random records and found none. Not shown to any buyer: its text is deleted once measured.

  3. A buyer's evaluation

    What leaves: A de-identified sample a buyer reads under an NDA, sent by you to the buyer.Who does what: The same engine on your computer, with the delivery's review: records read at random until the upper bound on what is missed is under the threshold.The bar: The delivery checks, short of certification: the buyer reads it only under its signed confidentiality undertaking.

  4. Delivery to a buyer

    What leaves: The licensed records, de-identified, from you (or the provider you choose) to the buyer, not through us.Who does what: The engine or an independent provider rewrites; an independent provider tests and certifies before each transfer; the buyer signs the commitments.The bar: All the checks below, an evidence file with an expiry, a certificate, and the buyer's public and contractual commitments.

The rules

14 rules, each with its sources.

What we do, why, and the words of the law, standard or study behind it.

  1. Rule 1

    Nothing identifying leaves your computer

    The engine runs in your browser. Your original records, the list of people it builds and the key that links stand-ins stay on your computer; what can leave is the rewritten text and a report of counts.

    Software that de-identifies must not itself leak what it removes, and a pseudonym's secret must stay with whoever made it. A scrub that starts after a buyer has the raw files has already given the buyer what it meant to remove.

    Sources
  2. Rule 2

    Several kinds of evidence, never one detector

    Four layers: the people your exports list in their own structure (senders, authors, users, contacts), found wherever they are mentioned; patterns checked against each identifier's own rule (check digits, key formats); names from public dictionaries, greetings, titles and sign-offs; and your own lists of words to remove and to keep.

    Rule-based detectors are best at numbers and formats, learned ones at names, and no detector covers what only the company knows (its clients, codenames and people). Direct identifiers cannot be limited to a fixed list of categories.

    Sources
  3. Rule 3

    Every mention of a person, or the person is not protected

    A person counts as protected only when every mention of them is replaced. The engine links each person's name, first name, surname, address and handle to one stand-in, and we measure ourselves the same way.

    One mention left in clear text identifies the person in all the others; a recall averaged over mentions hides exactly that failure.

    Sources
  4. Rule 4

    Stand-ins from a secret key you keep, never a plain hash

    Each stand-in number comes from a keyed hash (HMAC-SHA-256) under a 256-bit key made on your computer, looked up in a table that holds hashes, never names. A new key for each delivery means two buyers' copies cannot be joined.

    A hash without a secret key is reversed by hashing every possible name, as happened to New York's taxi data; regulators treat such a code as an identifier.

    Sources
  5. Rule 5

    A stand-in stays the same within a file, unless the use needs more

    By default a person keeps one stand-in within each file and gets another in the next, so the clues about them cannot be gathered across the archive. Keeping one stand-in across the whole archive is a choice made for a buyer's stated use, and the linked copy then needs its own linkage test. Realistic stand-ins (fictional names) are offered for deliveries.

    A consistent pseudonym lets an attacker collect what a person says in many places, as journalists did with AOL's search logs. Realistic surrogates hide names the detector missed among the fakes.

    Sources
  6. Rule 6

    Details that identify together are coarsened and measured

    In tables, postcodes are cut to their first part (US ZIP codes to three digits, or 000 where those cover 20,000 people or fewer), birth dates to the year and ages to five-year bands topped at 90. Then every row is checked: a delivery may hold no combination of these details shared by fewer than 11 people.

    Most people are unique on postcode, birth date and sex alone. The threshold is the one the European Medicines Agency and Health Canada set for public clinical reports, a re-identification probability of 0.09; we hold every row to it, not an average.

    Sources
  7. Rule 7

    A person reads records picked at random

    Rules read every record; a person reads a random sample of the rewritten ones. With nothing found in n records, the share still holding an identifier is below 1 - 0.05^(1/n) at 95% confidence. A sample needs a short reading; a delivery needs enough records for that bound to fall below 1%. Anything found sends the run back.

    Free text does not de-identify in bulk; it needs human judgement. The method is the one used for regulated clinical reports: annotate a random sample, measure recall, and compare the upper 95% confidence limit with the threshold.

    Sources
    • “If the upper 95% confidence limit of the estimated risk was larger than the EMA and Health Canada recommended threshold of 0.09, then transformations were performed on the quasi-identifiers until the estimated upper risk limit was at or below 0.09.”

    • “Anonymising qualitative material can be time-consuming. It does not lend itself to bulk processing and can require careful human judgement to determine if people are still identifiable”

    • “Review the results of the trial de-identification. Correct any coding or algorithmic errors that are detected.”

  8. Rule 8

    The result is checked again, and again on arrival

    Every rewritten record is read a second time with no memory of the first pass, and the copy cannot be downloaded while that check finds anything. A sample is checked a third time by our server, with the same rules, before it is measured; anything found and it is refused and nothing is kept.

    Validation means examining the resulting files to make sure nothing identifying slipped through, not trusting the process that made them.

    Sources
  9. Rule 9

    Content is screened as well as names

    Records about health, children, beliefs, sex life, union membership, ethnicity, crime, biometrics or a person's finances are flagged, and so are HR matters, legal advice and other parties' confidential material. They are not removed by guesswork: you read them and leave them out unless you may share them.

    Removing names does not make an HR file or a client's confidential material yours to sell; objectors in the Spirit Airlines sale fought on exactly that.

    Sources
  10. Rule 10

    An independent provider tests and certifies before each transfer

    Before a buyer receives anything, a de-identification provider you choose (not the buyer, and not us) tests the copy as an attacker would, with the web, AI assistants and linkage to other data, and certifies it before each transfer, counting the people it found. Health data also needs an expert determination.

    Nobody outside can verify a private party's own scrub. In the Spirit Airlines sale the estate took a lower bid to keep the scrub independent, and the court-appointed ombudsman required a certificate before every transfer. A contract alone does not make data anonymous.

    Sources
  11. Rule 11

    The buyer commits, publicly and in writing

    Every licence binds the buyer not to re-identify or try to, not to link the data with other data to identify people, to bind anyone it passes data to on the same terms, to tell you and us if it finds identifiable data, and to accept oversight. We make the same public commitment ourselves.

    California, Texas, Virginia and the FTC define de-identified data by exactly these duties; without the contract and the public commitment, data is not de-identified in their sense, whatever was removed.

    Sources
  12. Rule 12

    An evidence file for every release, with an expiry

    Each run writes a report into the copy: the engine and dictionary versions, what was replaced by kind, the tables' smallest groups, what the second check and the human review found, and the checks passed or open. The certificate joins it. It expires after a year, or sooner when the data, the recipient, the purpose or the known attacks change.

    Methods and results have to be documented so that a regulator, a buyer's counsel or an expert can check them, and identifiability rises over time as information and technology change.

    Sources
  13. Rule 13

    We say de-identified, with the measured risk

    We call data de-identified and state the measured risk and the threshold it met. We call it anonymous only for a named recipient after the independent test, not as a label.

    No technical mechanism guarantees that de-identified data cannot be re-identified, and a regulator's draft guidance forbids calling identifiable data anonymous or de-identified.

    Sources
    • “this document uses the phrase de-identification to describe this process and recommends avoiding the phrase anonymization, which is typically used to indicate that the de-identification process cannot be reversed, and there is no technical mechanism to ensure that de-identified data cannot be re-identified.”

    • “controllers should not use descriptions like "anonymous", "de-identified" or "de-personalised" if individuals are actually still identifiable.”

  14. Rule 14

    The engine is measured on a public benchmark

    We measure the engine on two public benchmarks and publish the result for the part of each we did not look at while building: the Text Anonymization Benchmark, court judgments in which legal annotators marked every identifier, with its strict metric; and PrivacyBench, company Slack, email and document exports in which people marked every identifier by hand, scored with its authors' own scorer beside the engines they published. The scripts that measure it ship with the engine, and so do its tests.

    Detector accuracy varies with the text it reads, vendors' own numbers are rarely checked independently, and a pooled recall hides missed direct identifiers. A tool should be validated on the kind of data it will process.

    Sources
    • “although the standard, mention-level recall seems relatively good at first sight (around 0.7), a closer look a the entity-level recall over direct identifiers ERdi shows a much poorer performance (around 0.45).”

    • “de-identification tools should be validated for the specific kinds of data that the agency intends to use.”

    • “Presidio (default): entity-level recall on direct identifiers ERdi 0.460, on quasi-identifiers ERqi 0.758, precision 0.761. Neural NER (RoBERTa fine-tuned on OntoNotes v5, zero-shot): ERdi 0.940, ERqi 0.874, precision 0.441.”

    • “Tonic built this benchmark and the system that scores highest on it. For that reason this dataset and the metrics have been designed so that anyone can evaluate their own de-identification systems on this data and compare directly to the scores published here.”

The catalogue

What the engine finds, and what it does with each.

Straight from the engine's own catalogue, so this list and the code are the same list.

  • Name of a person
    Becomes
    A stand-in that keeps who-is-who[PERSON_3]
    How it is found
    The export's own list of people (senders, authors, assignees, Slack and CRM users) matched wherever they are mentioned, then dictionaries of given names and surnames (public US and Wikidata lists), greetings and sign-offs, titles and speaker labels.
  • Email address
    Becomes
    A stand-in that keeps who-is-who[EMAIL_3]
    How it is found
    Address syntax. Shared mailboxes (support@, sales@) and example domains stay; a person's address takes that person's stand-in.
  • Phone number
    Becomes
    A stand-in that keeps who-is-who[PHONE_3]
    How it is found
    International or grouped digit runs of 9 to 15 digits, with dates, versions and bare ids told apart.
  • Postal address or postcode
    Becomes
    A tag with no link[ADDRESS]
    How it is found
    House number and street in English, Dutch, German, French, Spanish and Italian forms; UK, Dutch, Canadian and US ZIP+4 postcodes by shape, other postcodes after a state or the word postcode.
  • Date of birth
    Becomes
    A tag with no link[BIRTHDATE]
    How it is found
    A date next to born, birthday, date of birth or DOB.
  • National identity or tax number
    Becomes
    A tag with no link[ID_NUMBER]
    How it is found
    Each country's format and check digit: US SSN and ITIN, UK National Insurance and NHS numbers, Dutch BSN, German tax id, French NIR, Belgian national number, Spanish DNI and NIE, Italian codice fiscale, Swedish, Danish, Norwegian and Finnish personal numbers, Polish PESEL, Indian Aadhaar and PAN, Canadian SIN, Brazilian CPF, Singapore NRIC, Australian TFN; company and tax register numbers (Dutch KvK and RSIN with its 11-proof, US EIN by its IRS prefix, also written in a form's boxes, EU VAT numbers); passports and driving licences after their name.
  • Card number
    Becomes
    A tag with no link[CARD]
    How it is found
    13 to 19 digits that pass the Luhn check and start like a card.
  • Bank account number
    Becomes
    A tag with no link[IBAN]
    How it is found
    IBAN shape and its mod-97 check; other account numbers after account or routing words.
  • Customer, employee or account number
    Becomes
    A stand-in that keeps who-is-who[ACCOUNT_3]
    How it is found
    A number or code right after customer, client, account, member, employee, staff, badge, patient, policy, order, case, application or user id; codes that carry their kind (SF-EMP-45731, ACC-201029); a code beside a person's email or phone in a contact line; every later code of the same shape in the same export (PFE-208814 once labelled an employee id makes PFE-219337 one too); masked numbers (****4126); every value in a column named that way; payment processors' customer, card, invoice and charge ids (Stripe's cus_, pm_, in_, ch_); SEPA creditor identifiers; and Bitcoin and Ethereum wallet addresses (Bitcoin by its checksum).
  • IP address
    Becomes
    A stand-in that keeps who-is-who[IP_3]
    How it is found
    Public IPv4 and IPv6 addresses; private and local ranges stay.
  • Device id
    Becomes
    A stand-in that keeps who-is-who[DEVICE_3]
    How it is found
    MAC addresses by shape; IMEI, advertising and device ids after their name.
  • User id or handle
    Becomes
    A stand-in that keeps who-is-who[HANDLE_3]
    How it is found
    Slack and Teams mentions, @handles in prose, LinkedIn member ids (ACoAA...), and user-id fields; a known person's handle takes that person's stand-in.
  • Personal or internal link
    Becomes
    A tag with no link[LINK]
    How it is found
    Profile links (LinkedIn, X, Facebook, Instagram, GitHub users, Calendly, WhatsApp, Telegram), private file and workspace links (SharePoint, OneDrive, Google Drive and Docs, Dropbox, Box, Notion, Confluence and Jira, Slack archives, meetings), links that carry an email address or a token, and links to an organisation the engine replaces.
  • Precise location
    Becomes
    A tag with no link[LOCATION]
    How it is found
    Latitude and longitude pairs with four or more decimals (about 11 metres).
  • Name of an organisation
    Becomes
    A stand-in that keeps who-is-who[ORG_3]
    How it is found
    The export's own email domains (hudsonandvine.com makes Hudson & Vine one wherever it is written), a legal or trade word after a capitalised name (Eastman Farms LLC, Meridian Studios), the name learned from it for the rest of the export, and the companies listed with the US Securities and Exchange Commission. Names you keep (usually your own company) stay.
  • Password, key or token
    Becomes
    Removed[SECRET]
    How it is found
    The published formats of AWS, Google, Azure, GitHub, GitLab, Slack, Stripe, Twilio, SendGrid, OpenAI, Anthropic and npm keys, private keys, JWTs, passwords in connection strings and links, and assignments to password, secret, token or key.
  • Term you asked to remove
    Becomes
    A stand-in that keeps who-is-who[TERM_3]
    How it is found
    The words you list, matched whole, in any case.

The numbers

Thresholds, set before anything is measured.

Each comes from published practice, and each is read by the engine from the same place this page reads it.

11

Smallest group of people sharing the same details a delivery may contain: the European Medicines Agency and Health Canada threshold, held for every row

300

Random records a person reads before a delivery; with none found, fewer than 1.0% still hold an identifier, at 95% confidence

150

Random records our AI reads in every sample on arrival, removing what it finds before the sample is measured and deleted

5

Groups smaller than this are flagged even in a sample: the NHS standard for strong anonymisation

90+

Ages from here up are reported as one group, as HIPAA's safe harbour requires

23

Three-digit US ZIP prefixes too thinly populated to keep, written as zeros instead

What names do not cover

Content is screened too.

These are flagged for the holder to read, not silently removed or silently passed.

Health

Health data is a special category (GDPR Article 9) and protected health information under HIPAA; it is sold only after an expert determination.

Children

Children's data has rules of its own (COPPA in the US, the GDPR's added protection for children in the EU) and is left out.

Sex life or orientation

A special category under GDPR Article 9.

Religious or political beliefs

Religious and philosophical beliefs and political opinions are special categories under GDPR Article 9.

Trade union membership

A special category under GDPR Article 9, and a protected activity under the US National Labor Relations Act.

Racial or ethnic origin

A special category under GDPR Article 9.

Criminal records

Criminal convictions and offences may be processed only under official authority or specific law (GDPR Article 10).

Biometric or genetic data

Biometric identifiers fall under Illinois BIPA and GDPR Article 9; genetic data under GDPR Article 9.

A person's finances

A named person's salary, debts or credit history is high-risk even when not a special category.

HR matters

Performance, discipline, dismissal and pay records stay about a person even with the name gone; buyers and courts expect them left out.

Legal advice

Communications with lawyers can be privileged; selling them can waive the privilege. The Spirit Airlines sale carved them out.

Third parties' confidential material

A customer's or vendor's material shared under an NDA is not the holder's to sell, whatever is replaced.

Out of scope

What we do not take to market, de-identified or not.

Some data cannot be de-identified reliably. It is left out unless the condition is met.

  • Health information from care, insurance or a health client

    We leave it out.

    • “determines that the risk is very small that the information could be used, alone or in combination with other reasonably available information, by an anticipated recipient to identify an individual”

  • Recordings of voices and pictures of faces

    Unless the people in them consented in writing to AI training and sale; transcripts are rewritten instead.

  • Data about children

    We leave it out.

  • Customer transaction systems (orders, payments, loyalty profiles)

    Unless taken out whole rather than scrubbed, as in the Spirit Airlines sale.

Said plainly

What no tool solves.

De-identification lowers risk; it does not end it. These risks stay, and the licence and the independent test are built around them.

  • Writing style

    Long texts by one author can identify them by style even with every name gone. We flag small groups; we cannot rewrite how people write.

  • What a trained model remembers

    A model trained on the data can repeat what the scrub missed. The licence requires the buyer's own controls on training and outputs.

  • Combinations of ordinary facts

    A role, a project, a date and a place can single someone out in prose where no table check reaches. The human review and the independent attacker test are there for this.

The market

How others do it.

From our research into buyers, vendors, marketplaces and the courts.

  • Most buyers of company data

    Scrub in-house after receiving the files, publish no method or measured accuracy, and make the seller warrant consents and indemnify them.

  • The court in the Spirit Airlines sale

    Independent de-identification agent, quality-control testing, an affidavit before every transfer, the buyer's public commitment and flow-down; the estate preferred this to a higher bid that scrubbed in-house.

    • “The Debtors have structured the sale transaction so that a key component is having an independent expert conduct the deidentification of Spirit data. micro1 proposed to conduct the deidentification themselves and not to use an independent party.”

  • Data marketplaces

    Bar identifiable personal data in their terms and rely on the provider's own declaration and indemnity; none tests the de-identification.

Our commitment

We keep de-identified data de-identified.

  • We keep and use de-identified data only in de-identified form, and we do not attempt to identify anyone in it, alone or combined with other information.
  • In every licence we take part in, the buyer takes on the same commitment, and passes it on to anyone it shares the data with.
  • If data we hold turns out to identify someone, we delete that part and tell the holder.
  • This page describes our practice from public research. It is not legal advice; a holder's own counsel decides what their law requires.
De-identification standard | AIData.Broker