Let's Seal - Free open standard for document signing and verification

Show HN: Let's Seal – Let's Encrypt for document signing, free and self-hosted

Let's Seal is the open standard for proving any file is real and unaltered, acting as the 'Let's Encrypt' for document proof. This free, self-hosted solution uses the SEAL protocol to cryptographically verify file integrity, timestamp existence via Bitcoin, and confirm issuer identity. Supporting formats like PDF, images, and software artifacts, it offers a hosted web app, CLI tools, and APIs. Unlike paid notarization, it provides permanent, tamper-evident verification without vendor lock-in, ensuring authenticity is public infrastructure rather than a rental service.