Two kinds of signature
A simple electronic signature (SES) is the default. SignClearly confirms that the recipient controls the email address the link was sent to. It does not check who they are.
An advanced electronic signature (AES) adds an ID check of the recipient before signing, and the signer's certificate carries the name from their ID. It costs more credits than SES. You choose the kind for each document when you send it. Prices.
SignClearly does not provide a qualified electronic signature (QES). Whether a signature is accepted depends on your country and the type of document. SES, AES and QES compared.
The signed PDF
The signature and the field values are placed on your original pages. Nothing else on the pages changes. The signer reviews this exact file before signing, and its content does not change after they sign.
A digital signature from the signer's browser
When the recipient signs, their browser creates a one-time key and signs the file with it. SignClearly's own certificate authority issues a certificate for that key. The certificate carries the signer's email address and is valid for 24 hours, for this one signature.
The signature uses the PAdES format, so PDF readers such as Adobe Acrobat can check it. If anything in the file changes after signing, the check fails.
A second signature, the SignClearly seal, covers the final file. It shows that the file has not changed since SignClearly sealed it. It is not the signature of a person.
A certificate page
A page added at the end of the signed PDF lists the sender, the signer and the SHA-256 fingerprint of the original file. Below them is the event log up to the final review: the time in UTC, who acted and the IP address.
An event log with a hash chain
SignClearly records each step of the document: created, uploaded, sent, opened, access code entered, consent given, signed, completed, downloaded, and also declined, revoked or expired when that happens.
Each event includes the SHA-256 of the event before it, so an edit to an earlier event breaks the chain. Each event also gets a keyed checksum (HMAC) made with a key kept outside the database.
Once a day the chain gets a timestamp from an independent time-stamping authority (RFC 3161), so a later edit would not match it.
What an audit trail proves, and what it does not.
An access code
You can protect the link with a code of 6 to 32 characters. The recipient enters it before the document opens. Share it by phone or chat rather than email, so that a forwarded email alone does not open the document. After five wrong attempts the link locks. SignClearly stores each attempt, not the code the recipient types.
An ID check of the signer
When you require an ID check, the recipient shows an ID document and takes a selfie with a third-party identity service before signing. The name on the ID must match the recipient name you entered: every name on the ID, in the same alphabet. If it does not match, they cannot sign.
The recipient has up to three attempts per link. SignClearly keeps the result of the check and the name on the ID, not images of the ID.
Control after sending
- Resend the invitation. It does not use a credit.
- Revoke the link if you sent the wrong file or to the wrong person.
- Set how long the link works, from 1 to 30 days.
- Make a copy of a closed document and send it again.
- Get the credits back for a document that is not signed. How credits work.
Nothing to install for the recipient
The recipient signs in a browser on a phone or a computer. They do not create an account. The signing page walks through consent, the signature, a review of the final PDF and the intent to sign. Every step in order.