How QCDS Preserves Attachment Evidence and Privacy

QCDS treats a signer Document Attachment as protected transaction evidence and separately controls how that evidence is presented in the Completed PDF. Choosing privacy-obscured PDF presentation does not delete or alter the protected original attachment.

The Original Attachment Is the Evidence Object

A completed Document Attachment resolves to its exact protected storage object. Before QCDS uses that attachment for completion, it requires an active object with the supported PNG/JPEG MIME type and verifies the stored object's SHA-256 against the final signer-field value.

That original file remains separate from the PDF presentation page. QCDS also uses stable Request-wide attachment numbering so references on source pages, attachment pages, Audit Trail entries, and Completed Package files refer to the same Attachment 01/02/03 identity.

Displayed Attachment Presentation

When Display in completed PDF is enabled, QCDS decodes the protected image and renders it into the attachment presentation page while preserving its aspect ratio.

The original protected file is not replaced by this rendered presentation.

Privacy-Obscured Presentation

When display is disabled, QCDS creates an intentionally irreversible presentation derivative for the PDF: it collapses the image to a maximum 10×10-pixel grid, enlarges that grid with nearest-neighbor sampling, adds a translucent white veil, and overlays a privacy notice.

This protects detail in the human-readable PDF, but it is not evidence deletion. The protected original still exists for authorized records access.

The Audit Trail Still Identifies the Original

The Completed PDF Audit Trail records whether the attachment was displayed or privacy-obscured and includes the original filename, MIME type, size, and original SHA-256. That gives the presentation page a verifiable relationship to the retained evidence object without embedding the original bytes into the Audit Trail text.

The Completed Package Preserves the Original File

When at least one signer attachment exists, QCDS offers a Completed Package. The ZIP contains the current verified Completed PDF artifact(s) plus every retained original signer attachment under an Attachments folder.

Access to that package is authenticated and workspace-authorized. Keep package downloads in appropriately controlled records storage because they may contain the unobscured originals even when the PDF itself intentionally hides their visual detail.

Community Discussion

Want to compare workflows, share practical tips, or discuss how you use this QCDS feature? Visit the QC Digital Signature Community. For private support, bug reports, account-specific issues, or feature requests, use the QuantaCade support system.