Replace a column's values with a cryptographic hex digest - to pseudonymize identifiers, build join keys, or fingerprint rows - without your data ever leaving the browser.
Load a CSV, pick the column, choose an algorithm, and download a file where that column holds a hex digest of each value. Every byte is processed locally in JavaScript.
Drop in your file and choose the column to hash - an email, customer ID, license key, or any field you want to turn into a fixed-length digest. The column dropdown lists every header it detects.
Select MD5, SHA-1, or SHA-256 (the default). Each cell is UTF-8 encoded and hashed to a lowercase hex string. Tick 'Keep original column' if you need the source value next to its hash for verification.
The tool writes a new column named <col>_<algo> and exports RFC-4180 CSV with the digests in place. Identical inputs always produce identical hashes, so the output is stable across runs and files.
Hashing turns sensitive or unwieldy values into deterministic fixed-length tokens. Doing it locally means the original data is never transmitted - the privacy guarantee is structural, not a promise.
Swap raw emails, phone numbers, or account IDs for digests so downstream analysts can group and join without ever seeing the underlying personal data.
A SHA-256 of a normalized field gives every dataset the same key for the same value, so you can match records across files without sharing the plaintext.
Hash a column to detect duplicate or changed values quickly - identical content collapses to an identical digest you can sort and compare.
MD5, SHA-1, and SHA-256 are implemented in pure JavaScript and run in your tab. No upload, no server, no telemetry - close the tab and nothing remains.