Security & File Handling

Zero-retention security model

PDFKite V4 separates documents from workflow metadata. Document bytes stay in the browser or on a customer-controlled endpoint. Hosted PDFKite APIs are JSON-only, use strict request-size limits, and have PHP file uploads disabled.

Integrity

Enterprise envelopes identify the intended document by SHA-256. The signing editor verifies the selected local file against that hash before the signer can complete an envelope.

Certificate signing

The optional Local Agent supports PKCS#12/PFX certificate-backed PDF signatures and can request the ETSI.CAdES.detached subfilter used for PAdES-style signatures. Whether Acrobat displays a signature as trusted depends on the signer's certificate chain and trust anchor. A trusted CA/TSP credential is not supplied by PDFKite.

Audit events

Enterprise metadata records consent and signing events without storing the PDF. Events are chained with HMAC-SHA-256 so the audit endpoint can detect later event tampering when the audit secret remains protected.

Compliance boundary

Software features alone do not create HIPAA, SOC 2, ISO 27001, eIDAS, 21 CFR Part 11, or other certifications. Those outcomes require contracts, validated operational controls, policies, identity processes, trusted service providers where applicable, and independent review.