FernSign

Every signature grows its own fern.

Each sealed file's SHA-256 digest grows a fern. Change one byte and a different fern grows.

Start signingGrow one from a file
msa-halvorsen.pdf0 points
1d24126884acdd64472092310706594d155d9ab2e634c2ed3ad587c0a966c819
  • Master Services Agreement
    Halvorsen Joinery1d2412…c819
  • Lease Amendment, Unit 4B
    311 Atlantic Ave7c164a…548a
  • Mutual NDA
    Kestrel Bio10d895…a226
  • Change Order 07
    Ortega Roofing09b795…75e7
  • Offer Letter
    Priya Ramanathan57102c…3abb
  • Vendor Onboarding
    Dunmore Freighte541a1…89fd
  • Photo Release
    Saltmarsh Studio3921fd…6ccf
  • Consulting SOW, Q3
    Ilse Brandt7b1425…c508
  • Sublease Consent
    18 Bleecker St34bc3e…5747
  • Equipment Rental
    Northgate AV1f28b1…efab

A signature opens one turn at a time.

  1. 01Upload

    Drop in the PDF. FernSign hashes it on arrival, so the original is on record before anyone touches it.

  2. 02Place fields

    Mark where each person signs, initials or dates. Every field belongs to a named signer.

  3. 03Send

    Signers get an email link and sign in the browser. They don't need an account.

  4. 04Sign

    Each signer types, draws or adopts a signature. Every action is logged with time, IP and device.

  5. 05Seal

    After the last signature the PDF is flattened and hashed again. The final digest grows the fern.

Try it with your own file

Change one byte. Watch the fern change.

Your file is hashed in this browser with Web Crypto. It is never uploaded.

Drop a file here, or choose one
Any type, up to 50 MB
Original

The digest of your file appears here.

One byte changed

Hashing the sample…

The new digest appears here, with every changed character lit.

Thirty-two bytes, and each one has a job.

Tap any byte to change it and regrow the fern. A real digest can't be steered like this: it comes from the file.

Curlbytes 4-5

How hard the whole frond bends to one side.

What you keep

A sealed PDF, and a certificate that shows its fern.

Certificate of completion
Master Services Agreement, Halvorsen Joinery
Sample
Final SHA-256
1d24126884acdd64472092310706594d155d9ab2e634c2ed3ad587c0a966c819
Pages
6
Sealed
Mar 3, 16:52 EST
Signers
  • Maren Halvorsen · Halvorsen JoineryMar 3, 10:14 EST
  • Tobias Wren · ClientMar 3, 16:52 EST

Legally binding

Signatures meet the U.S. ESIGN Act and UETA for most business agreements.

Full audit trail

Opens, views and signatures, each with time, IP address and device.

Encrypted storage

Documents are encrypted in transit and at rest.

Digest on the certificate

The final SHA-256 is printed beside the fern, so anyone can check it.

Questions people ask first.

Is the fern the security feature?

No. The SHA-256 digest is the proof. The fern is a way to see it: two different digests almost never grow look-alike ferns, but a match is always decided by comparing the digests, which the Verify tool does for you.

Are FernSign signatures legally binding?

For most business agreements in the United States, yes, under the federal ESIGN Act and state UETA laws. A few document types, such as wills and some court and family-law filings, still need wet ink. Check with counsel when in doubt.

Do my signers need an account?

No. They get an email link, review the document in the browser and sign. Only the sender needs a FernSign account.

Does the Verify tool upload my file?

No. The file is read and hashed inside your browser with Web Crypto. Only the 64-character digest is ever compared.

What do I get when a document is sealed?

A flattened PDF, a certificate of completion with the final digest and fern, and the full event history for every signer.

Why does my account need verification before I can send?

Every sending account is reviewed by a person, which keeps impersonation and phishing off the platform. Most reviews finish within one to two business days.

Plant your first document.

Create an account, get verified, and send your first envelope today.

Start signing