Digital Certificate Signature
Cryptographically sign PDF documents using PKCS#12 (.p12 / .pfx) digital certificates and inspect/validate existing CMS signatures in the browser.
Apply genuine cryptographic PKCS#7 / CMS digital signatures using your PKCS#12 (.p12 / .pfx) certificate directly in the browser. You can also inspect and validate existing digital signatures for byte-level document integrity and tamper evidence.
How to use Digital Certificate Signature in 3 simple steps
Select Your Files
Drag and drop your document directly into the browser. Your file stays on your hardware and is never transmitted across the network.
Configure Options
Customize parameters, page sequence, orientation, or compression presets with instant interactive live feedback.
Save & Download
Click the action button. The new document is compiled in memory and downloaded straight to your device.
Frequently Asked Questions
How does in-browser cryptographic signing work without uploading my private key?
PDFMiniFly runs WebAssembly and local cryptographic engines (node-forge and Web Crypto) inside your browser tab to decrypt your .p12 bundle and compute the SHA-256 ByteRange signature in memory. Your private key and password never leave your device.
Can I test digital signing if I do not have a .p12 certificate file?
Yes. The tool features a built-in test certificate generator that generates an authentic 2048-bit RSA self-signed X.509 certificate in browser memory in seconds.
Are my files uploaded to a server?
No. PDFMiniFly processes everything locally inside your browser. Your document never leaves your device, and once the app is installed it also works offline.
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