Xbase++

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.

Xbase++

LOCAL nSuccess
LOCAL oCrypt
LOCAL oCert1
LOCAL oCert2
LOCAL cInFile
LOCAL cP7sFile
LOCAL cExtractedToFilePath

nSuccess := 0

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

oCrypt := CreateObject("Chilkat.Crypt2")

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

oCert1 := CreateObject("Chilkat.Cert")
nSuccess := oCert1:LoadPfxFile("qa_data/pfx/cert_test123.pfx", "test123")
IF (nSuccess != 1)
    ? oCert1:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    RETURN
ENDIF

oCert2 := CreateObject("Chilkat.Cert")
nSuccess := oCert2:LoadPfxFile("qa_data/pfx/test_secret.pfx", "secret")
IF (nSuccess != 1)
    ? oCert2:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    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.
nSuccess := oCrypt:AddSigningCert(oCert1)
IF (nSuccess != 1)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    RETURN
ENDIF

nSuccess := oCrypt:AddSigningCert(oCert2)
IF (nSuccess != 1)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    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. 
oCrypt:CadesEnabled := 1

oCrypt: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.
cInFile := "qa_data/pdf/sample.pdf"
cP7sFile := "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.
nSuccess := oCrypt:CreateP7M(cInFile, cP7sFile)
IF (nSuccess == 0)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    RETURN
ENDIF

//  Verify the .p7s file and extract the original file from the .p7s. 
cExtractedToFilePath := "qa_output/sample.pdf"
nSuccess := oCrypt:VerifyP7M(cP7sFile, cExtractedToFilePath)
IF (nSuccess == 0)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oCert2:destroy()
    RETURN
ENDIF

? "Success!"

oCrypt:destroy()
oCert1:destroy()
oCert2:destroy()