That is a visual signature, the everyday kind. When the other side needs proof the file has not changed since signing, Certify adds a real PAdES-style signature: a 2048-bit RSA key generated non-extractable in your browser, or your own .p12/.pfx certificate decrypted and imported on the device, signs a detached CMS signature into the PDF, optionally with an RFC 3161 trusted timestamp, and Acrobat or any reader verifies it. Verify signatures checks any signed PDF the same way, locally. The private key never leaves the machine — including to Bindery.
How it works
- Open Bindery in Firefox or Chrome and drop the PDF into Sign
- Draw or type your signature and click where it belongs
- Download — or use Certify for a cryptographic signature with a local key
Questions people ask
Can I use my own certificate on Linux?
Yes, in Certify: import a .p12 or .pfx file — PBES2/AES, legacy 3DES and RC2-40 encodings are decrypted in the browser — and the key is stored non-extractable in your browser, never sent anywhere. RSA and ECDSA keys are supported, and the full chain is embedded in the signature.
Is a drawn signature legally valid?
For most everyday agreements a visible signature on the document is what the parties expect. It is not a cryptographic signature; where tamper evidence or a certificate is required, use Certify, and for regulated workflows a qualified provider may be needed.
Does the signing key sync between my machines?
No — a key generated in the browser is non-extractable by design and stays in that browser’s IndexedDB. An imported certificate can be imported again on another machine from the same .p12 file. Signature images, by contrast, can sync with a Pro account.