PdfCmsDigitalSignature.CertificateChain Property

Gets or sets the certificate chain.

C#

public X509Certificate2[] CertificateChain { get; set; }

An array of System.Security.Cryptography.X509Certificates.X509Certificate2 objects representing the chain associated with the signing certificate

The certificates in the chain must be in "ascending" order. The first certificate is the parent of PdfBaseDigitalSignature.Certificate, the second certificate is the parent of first one and so on.
When this property is set, the PdfDigitalSignature.CertificateIncludeOption property is ignored.