Remove Digital Signatures
This demo searches for signature fields and erases their values and empty their appearance.
PHP
<?php // load and register the autoload function require_once '../../../../../bootstrap.php'; // prepare some files $files = [ $assetsDirectory . '/pdfs/tektown/Laboratory-Report-signed.pdf', $assetsDirectory . '/pdfs/lenstown/Laboratory-Report-signed-PAdES.pdf', $assetsDirectory . '/pdfs/camtown/Laboratory-Report-signed.pdf', ]; $path = displayFiles($files, false); $writer = new \SetaPDF_Core_Writer_Http(basename($path)); $document = \SetaPDF_Core_Document::loadByFilename($path, $writer); // get all terminal fields $terminalFields = $document->getCatalog()->getAcroForm()->getTerminalFieldsObjects(); // iterate over the fields foreach ($terminalFields AS $fieldData) { /** @var \SetaPDF_Core_Type_Dictionary $fieldData */ $fieldData = $fieldData->ensure(); // ensure that the field is a signature field $ft = \SetaPDF_Core_Type_Dictionary_Helper::resolveAttribute($fieldData, 'FT'); if (!$ft || $ft->getValue() !== 'Sig') { continue; } // if no value is set (not signed) continue if (!$fieldData->offsetExists('V')) { continue; } // unset the value $fieldData->offsetUnset('V'); // clear the appearance stream. $ap = $fieldData->getValue('AP'); if (!$ap) { continue; } /** @var \SetaPDF_Core_Type_Dictionary $ap */ $ap = $ap->ensure(); $n = $ap->getValue('N'); if ($n) { /** @var \SetaPDF_Core_Type_Stream $n */ $n = $n->ensure(); $n->setStream('%% Blank'); } } // done $document->save(false)->finish();