Anonymize structured data locally with CloakData

Try 10,000 rows free per installation. Prepare safer working copies of structured data before development, testing or other approved downstream use. CloakData runs in the CloakDoc Windows desktop app and is included with Pro and Enterprise, with up to 1,000,000 records per run across all selected tables.

From source data to a sanitized working copy

1. Import: open CSV, XLS and XLSX data.
2. Review: inspect tables and choose what each field should do.
3. Relate: assign matching key columns to a relationship group when tables must stay joinable.
4. Mask: keep, consistently tokenize or redact selected values locally.
5. Export: save transformed copies and review them before downstream use.

A simple related-table example

Keep matching keys consistent

Assign primary and foreign-key columns to the same relationship group. With the same secret workspace key, the same exact value produces the same token across supported formats and later runs. For example, customer_id in a customer table can use the same group as buyer_id in an orders table.

Matching is exact and case-sensitive. Leading zeros are meaningful; 001 and 1 remain different. Empty cells remain unchanged. Tokens are text and do not retain the source field type or length. Existing missing foreign keys and duplicate primary keys are not repaired or certified.

Choose fields deliberately

For each field, keep the original, replace it with a consistent token, or redact it. Review every field that remains unchanged. CSV files require UTF-8 encoding and unique, nonempty column headers. Only CSV, XLS and XLSX files are supported. XLS imports are limited to 32 MiB.

CSV, XLS and XLSX

CSV files are streamed and exported as CSV. Excel worksheets are processed as separate tables and exported as new values-only XLSX workbooks with text cells. Formulas and merged cells must be resolved first. Workbook styling, comments and metadata are not copied; Excel date values remain stored serial values. Hidden worksheets are included in the table list for review.

Process large tables locally

A background worker streams records and writes results into local browser storage. The record limit excludes headers. Each record is limited to 8 MiB of text, and Excel cells retain Excel's 32,767-character limit. Available disk space and processing time affect capacity. A failed run does not publish partial output files.

Protect the workspace key and output

Save your workspace key securely if later exports must match. It is not uploaded or automatically persisted. Working files remain on the device until cleared; an interrupted session can leave local files. Clear site storage to remove abandoned workspace data. Pseudonymization is not a guarantee of anonymity or legal compliance.