Lianja

Create CMS Signed File (PDF) with Multiple Signing Certificates

See more Digital Signatures Examples

Demonstrates how to sign a file by adding multiple signatures (multiple certificates). This example signs a PDF file to produce an output file that is a CMS signature wrapping the original PDF. (Note: This is different than modifying a PDF by injecting a signature into the PDF file format.)

Note: This example requires Chilkat v9.5.0.83 or greater.

Lianja

llSuccess = .F.

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

loCrypt = createobject("CkCrypt2")

// ------------ This example requires Chilkat v9.5.0.83 or greater.

loCert1 = createobject("CkCert")
llSuccess = loCert1.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
if (llSuccess <> .T.) then
    ? loCert1.LastErrorText
    release loCrypt
    release loCert1
    return
endif

loCert2 = createobject("CkCert")
llSuccess = loCert2.LoadPfxFile("qa_data/pfx/test_secret.pfx","secret")
if (llSuccess <> .T.) then
    ? loCert2.LastErrorText
    release loCrypt
    release loCert1
    release loCert2
    return
endif

// ------------ This example requires Chilkat v9.5.0.83 or greater.

// Tell the crypt component to use both certificates for signing. 
// When we create the signature, it will be signed by both certificates.
llSuccess = loCrypt.AddSigningCert(loCert1)
if (llSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert1
    release loCert2
    return
endif

llSuccess = loCrypt.AddSigningCert(loCert2)
if (llSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert1
    release loCert2
    return
endif

// The CadesEnabled property applies to all methods that create PKCS7 signatures. 
// To create a CAdES-BES signature, set this property equal to true. 
loCrypt.CadesEnabled = .T.

loCrypt.HashAlgorithm = "sha256"

// We can sign any type of file, creating a .p7s as output.
// The .p7s contains the signature and also embeds the data of the file that is signed.
lcInFile = "qa_data/pdf/sample.pdf"
lcP7sFile = "qa_output/sample.pdf.p7s"

// Create the CAdES-BES attached signature, which contains the original data.
// Note: Chilkat's function naming is not accurate.  CreateP7M creates a PKCS7 signature where the signed file
// is contained within the signature.  CreateP7S creates a detached PKCS7 signature where the signed file
// is NOT contained within the signature.  We want the data to be contained in the signature, therefore
// we call CreateP7M even though we are naming our output file .p7s.
llSuccess = loCrypt.CreateP7M(lcInFile,lcP7sFile)
if (llSuccess = .F.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert1
    release loCert2
    return
endif

// Verify the .p7s file and extract the original file from the .p7s. 
lcExtractedToFilePath = "qa_output/sample.pdf"
llSuccess = loCrypt.VerifyP7M(lcP7sFile,lcExtractedToFilePath)
if (llSuccess = .F.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert1
    release loCert2
    return
endif

? "Success!"


release loCrypt
release loCert1
release loCert2