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Basic PDF Digital Sign Service

This workflow provides a complete PDF digital signature service, covering the generation of digital certificates, the uploading of certificates and PDF files, the processing of digital signatures, and the downloading of signed documents. Through precise parameter validation and secure encryption technology, the reliability and security of the entire process are ensured. This service is suitable for electronic document management, remote work, and third-party system integration, aiming to simplify the digital signature process, improve work efficiency, and ensure the authenticity and security of documents.

Workflow Diagram
Basic PDF Digital Sign Service Workflow diagram

Workflow Name

Basic PDF Digital Sign Service

Key Features and Highlights

This workflow delivers a comprehensive PDF digital signature service, supporting digital certificate generation, certificate and PDF file uploads, PDF digital signing, and post-signature file downloads. It incorporates multi-level parameter validation to ensure input accuracy and security. Leveraging Node.js cryptographic libraries such as node-forge and specialized PDF signing libraries like @signpdf/signpdf, it achieves efficient and secure digital signing operations.

Core Problems Addressed

  • Automated generation of compliant digital certificates and key files (PFX, PEM formats).
  • Support for user uploads of certificates and PDFs to be signed, with validity checks.
  • Implementation of PDF digital signatures to guarantee file integrity and identity authentication.
  • Full-process automation of file upload, signing, and download via API interfaces.
  • Robust error handling and response feedback to ensure stable API invocation.

Application Scenarios

  • Automated digital signing of contracts, agreements, and other legal documents within enterprise electronic document management systems.
  • Remote or paperless office environments requiring simplified certificate management and document signing workflows.
  • Development of digital signature API services for third-party system integration.
  • Any scenario requiring legally compliant and secure digital signing of PDF files.

Main Process Steps

  1. Request Handling and Method Routing
    Accept POST requests via Webhook API and route operations based on the method field in the request body (upload, genKey, signPdf, download).

  2. Upload Validation and Storage

    • Validate parameters according to upload type (PDF document or signing key).
    • Convert uploaded file data into files and save them to designated server directories.

  3. Digital Certificate and Key Generation

    • Validate required parameters for certificate generation (subject name, issuer name, serial number, validity period, and password).
    • Use node-forge to generate RSA key pairs, create self-signed certificates, and output PFX and PEM format files.

  4. PDF Digital Signing

    • Validate parameters needed for signing (input PDF filename, PFX certificate file, and password).
    • Read the PDF file and add a signature placeholder.
    • Digitally sign the PDF using the P12 certificate, producing a signed PDF file.

  5. File Download Handling

    • Retrieve the specified file per request, set response headers for attachment, and support file download.

  6. Response Feedback

    • Return success or error messages to the caller based on the execution results of each step.

Involved Systems or Services

  • n8n workflow automation platform and its nodes (Webhook, code nodes, file read/write nodes, conditional nodes, etc.)
  • Node.js cryptography library: node-forge
  • PDF signing-related libraries: @signpdf/signpdf, @signpdf/signer-p12, @signpdf/placeholder-plain
  • Local file system (for temporary storage of uploaded and generated files)

Target Users and Value

  • Software developers and system integrators needing to rapidly build digital certificate management and PDF signing interfaces.
  • Enterprise IT departments aiming to automate electronic document signing and management to improve operational efficiency.
  • Professionals in legal, finance, and related fields requiring document authenticity and security assurance.
  • Third-party application developers needing remote access to digital signature services.

This workflow employs a modular design to automate the entire process of digital certificate generation, upload management, PDF digital signing, and file download. Its rigorous parameter validation and error feedback mechanisms ensure service reliability and security, making it an ideal solution for building electronic signature platforms or integrating digital signature functionality.

Basic PDF Digital Sign Service