Decrypt the document using X.509 certificate

First load the document as described in the corresponding how-to article.

Check the value of Encrypted property of TElPDFDocument class to check that the document is encrypted.

If the document is encrypted using X.509 certificates, an instance of TElPDFPublicKeySecurityHandler class is contained in EncryptionHandler property of TElPDFDocument class.

Add the certificate(s), which will be used for decryption, to CertStorage property of TElPDFPublicKeySecurityHandler class.

Call Decrypt() method of TElPDFDocument to decrypt the document.

Save and close the document using Close() method.