Safe hashing for suppression & duplicate lists
Share your list securely — not your customers' emails.
Hash List turns a column of emails or phone numbers into MD5 or SHA-256 hashes on your own computer. Your partner gets the hashed list they need to dedupe or suppress. The raw contact data never leaves your machine.
Files are processed locally. We never upload your spreadsheet, values, or hashes.
Sharing a list shouldn't mean sharing your customers
Marketing partners often need your list to remove duplicates or suppress existing contacts. But emailing over a spreadsheet of raw addresses and phone numbers hands them data you were trusted to protect. Hashing solves it: the same value always produces the same hash, so partners can still match records — without ever seeing the original email or phone number.
Stays on your computer
The spreadsheet, the values, and the hashed output are processed locally. Nothing is uploaded to our servers — ever.
Deterministic & matchable
Identical inputs always produce identical hashes, so your partner can dedupe and suppress against their own hashed data.
Works offline
After a quick license check, hashing runs with no internet connection required. The processing engine never phones home.
Everything you need, nothing you don't
A focused desktop utility — no dashboards, no integrations, no data leaving your machine.
MD5 & SHA-256
Pick the exact hash your marketing partner asks for. Lowercase hex, UTF-8, deterministic output.
CSV & Excel
Import .csv, .xlsx, and .xls.
Multi-sheet workbooks let you choose the right sheet.
Smart normalization
Email, phone, and generic modes clean up formatting before hashing — lowercasing emails, stripping phone punctuation — so matches line up.
One clean output
Replace just the selected column, or export the hashed column on its own. The plaintext value is never written to the output file.
Handles large files
Streamed, batched processing with a live progress bar and a cancel button keeps the app responsive on big lists.
Clear summaries
See exactly how many values were hashed, left blank, or skipped as invalid — no guessing, no silent failures.
How it works
Four steps from spreadsheet to shareable hashed list.
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1
Install & sign in
Download Hash List for Mac or Windows and sign in with your account.
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2
Pick a column
Open your CSV or Excel file and choose the column you want to hash.
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3
Choose format & hash
Select email, phone, or generic — then MD5 or SHA-256. Preview the result.
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4
Save the hashed CSV
Generate a clean, hashed file to hand to your marketing partner.
Create your account
Sign up here and continue to secure Stripe Checkout. We'll email a confirmation link — after you confirm, download Hash List and sign in with the same email.
- $49.99 per year — cancel anytime
- Use it on up to 2 devices
- Mac (Apple Silicon & Intel) and Windows
Check your email
We sent a confirmation link to your inbox. Click it to verify your account — you'll come right back here to continue to payment.
- Open the email from Data Hash Secure
- Click the confirmation link
- Continue to secure Stripe Checkout
Didn't get it? Check your spam folder, or .
Simple pricing
One plan. No tiers, no per-seat surprises.
- MD5 & SHA-256 hashing
- CSV & Excel (multi-sheet) import
- Email, phone & generic normalization
- Up to 2 devices
- Works offline (~14-day grace after each check)
- Automatic signed updates
- Cancel anytime via the Stripe billing portal
Questions
Is my contact data uploaded anywhere?
No. Your spreadsheet, the original values, and the hashed output are all processed on your own computer. Our servers only handle your account, subscription, and app updates.
Which hash should I choose — MD5 or SHA-256?
Use whichever your marketing partner requests. Hash List produces both in the exact format platforms expect: lowercase hexadecimal, no spaces or prefixes.
Does it run on Mac and Windows?
Yes — there's a Windows installer and macOS builds for both Apple Silicon and Intel. One subscription covers up to 2 devices.
Can I use it offline?
After a quick license check, hashing works without an internet connection for roughly 14 days before it needs to re-validate. The processing itself never requires the internet.
How do I cancel or update billing?
Sign in at datahashsecure.com/billing to open the Stripe billing portal — cancel, update payment methods, and view past invoices. The desktop app’s Manage billing button opens the same page.
Download Hash List
Already subscribed? Install the app and sign in with the same email.