Digitally Sign Any File in Your Browser: Without Uploading Files or Installing Software — 100% Local, Private, and Secure.

Secure Digital Document Signing Without Uploading Files or Installing Software ## What This Tool Does ## Key Privacy and Security Advantages ## What Types of Files Can Be Signed? ## How Digital Signature Verification Works ## Ideal Use Cases ## Why This Approach Matters ## By leveraging client-side cryptography, it ensures: ## Try the Tool Instantly Digital signatures are a foundational requirement for secure document exchange, software distribution, compliance workflows, and data integrity validation. However, most online signing tools introduce privacy risks by uploading files to remote servers or forcing user accounts and installations. This browser-based Digital Document Signer solves that problem by performing all cryptographic operations locally using the Web Cryptography API. Files never leave the device, no software is installed, and no registration is required. This tool enables users to: All operations occur entirely inside the browser, ensuring maximum privacy and security. 1. Local-Only Data Processing All keys, files, and signatures are generated and processed locally in the browser. Nothing is uploaded, stored, or transmitted to a server. 2. No Registration or Accounts The tool can be used immediately without creating an account or sharing personal information. 3. No Downloads or Installations Runs directly in modern browsers. No plugins, no executables, no dependencies. 4. Private Keys Never Leave the Device The private signing key remains under full user control and is never transmitted over the network. 5. Industry-Standard Cryptography Uses RSA-PSS (2048-bit) with SHA-256 via the Web Cryptography API — a modern and secure standard. The signing process operates on raw binary data, making it format-agnostic. This includes: If the file can be opened in a browser, it can be signed. Signature verification requires only three items: If verification succeeds, the file is guaranteed to be: Any modification to the file—even a single byte—will invalidate the signature. Many “free” online signing tools trade convenience for privacy by storing files on external servers. This tool takes the opposite approach: privacy by design. The Digital Document Signer works instantly in the browser: Try it now and sign or verify documents securely in seconds. Templates let you quickly answer FAQs or store snippets for re-use. Are you sure you want to hide this comment? It will become hidden in your post, but will still be visible via the comment's permalink. Hide child comments as well For further actions, you may consider blocking this person and/or reporting abuse - Generate secure cryptographic key pairs - Digitally sign any file type - Verify document authenticity and integrity - Detect tampering with mathematical certainty - PDFs, DOCX, XLSX, TXT - JSON, XML, HTML - Images (PNG, JPG, GIF) - Audio and video files (MP3, MP4) - ZIP archives and software binaries - The original file - The digital signature file (.sig) - The signer’s public key - Signed by the holder of the corresponding private key - Secure document exchange - Contract verification - Open-source file distribution - Compliance and audit trails - Software integrity checks - Sensitive data sharing - Zero data leakage risk - Full user ownership of cryptographic keys - Transparent and verifiable security behavior - No installation - No file uploads - No tracking of document content