Data Anonymizer

Q: Is sensitive data uploaded?

No. Parsing, hashing, tokenization, masking, previews, persistence, and export run in your browser. Raw values do not enter BaseToolbox analytics.

Q: What is the difference between hashing and tokenization?

A salted hash is irreversible in this tool. Tokenization creates a stable replacement plus a separate vault that maps tokens back to raw values.

Q: Does the manifest contain original values?

No. It contains rule type, stable column ID, changed count, and irreversibility status only. The optional token vault is separate and explicitly marked sensitive.

Q: Is anonymized data automatically safe to publish?

Not necessarily. Quasi-identifiers, small groups, rare values, and external datasets can enable re-identification. Review the result under your own privacy and legal requirements.

Anonymize selected CSV or Excel columns locally with masking, SHA-256 hashing, stable tokenization, or redaction. Review before and after previews, irreversible rules, a raw-value-free manifest, and separate sensitive token-vault export.

Saved sessions

Drop a sensitive CSV, TSV, or XLSX file here

The source stays in this browser. Legacy .xls files are not supported.

Sensitive data stays in this browser

Source values, salts, rules, previews, anonymized output, and token vaults remain in your browser and are excluded from BaseToolbox analytics. The manifest records counts and rule types but never raw values.

Current limitations

CSV, TSV, and modern XLSX are supported; legacy .xls, macros, and desktop-Excel formula recalculation are not.
Column rules do not discover every sensitive field automatically. You must select every identifier, quasi-identifier, and confidential column that needs protection.
Hashing can still be vulnerable to guessing when values come from a small domain. Use a strong private salt and assess re-identification risk before sharing data.
Browser storage may be cleared or reclaimed. A downloaded token vault contains raw values and must be handled as sensitive data.

How local data anonymization works

Select columns and explicit rules

Choose masking, hashing, tokenization, redaction, or no change by stable imported column ID.

Apply deterministic transformations

The browser processes bounded row chunks and uses the same salt to create repeatable hashes or tokens.

Review and separate exports

Compare before and after previews, export anonymized CSV/XLSX and a raw-value-free manifest, and keep any token vault separate.

Data anonymizer FAQ

Is sensitive data uploaded?

What is the difference between hashing and tokenization?

Does the manifest contain original values?

Is anonymized data automatically safe to publish?

Map spreadsheet columns Clean CSV or Excel data

Data Anonymizer

Saved sessions

Drop a sensitive CSV, TSV, or XLSX file here

The source stays in this browser. Legacy .xls files are not supported.

Sensitive data stays in this browser

Current limitations

CSV, TSV, and modern XLSX are supported; legacy .xls, macros, and desktop-Excel formula recalculation are not.
Column rules do not discover every sensitive field automatically. You must select every identifier, quasi-identifier, and confidential column that needs protection.
Hashing can still be vulnerable to guessing when values come from a small domain. Use a strong private salt and assess re-identification risk before sharing data.
Browser storage may be cleared or reclaimed. A downloaded token vault contains raw values and must be handled as sensitive data.

How local data anonymization works

Select columns and explicit rules

Choose masking, hashing, tokenization, redaction, or no change by stable imported column ID.

Apply deterministic transformations

The browser processes bounded row chunks and uses the same salt to create repeatable hashes or tokens.

Review and separate exports

Compare before and after previews, export anonymized CSV/XLSX and a raw-value-free manifest, and keep any token vault separate.

Data anonymizer FAQ

Is sensitive data uploaded?

What is the difference between hashing and tokenization?

Does the manifest contain original values?

Is anonymized data automatically safe to publish?

Map spreadsheet columns Clean CSV or Excel data

How local data anonymization works

Select columns and explicit rules

Apply deterministic transformations

Review and separate exports

Data anonymizer FAQ

Related spreadsheet tools

How local data anonymization works

Select columns and explicit rules

Apply deterministic transformations

Review and separate exports

Data anonymizer FAQ

Related spreadsheet tools