(Swift 3,4,5...) Create CMS Signed File (PDF) with Multiple Signing Certificates

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.

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

    let crypt = CkoCrypt2()!

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

    let cert1 = CkoCert()!
    var success: Bool = cert1.loadPfxFile("qa_data/pfx/cert_test123.pfx", password: "test123")
    if success != true {
        print("\(cert1.lastErrorText!)")
        return
    }

    let cert2 = CkoCert()!
    success = cert2.loadPfxFile("qa_data/pfx/test_secret.pfx", password: "secret")
    if success != true {
        print("\(cert2.lastErrorText!)")
        return
    }

    // ------------ 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.
    success = crypt.addSigning(cert1)
    if success != true {
        print("\(crypt.lastErrorText!)")
        return
    }

    success = crypt.addSigning(cert2)
    if success != true {
        print("\(crypt.lastErrorText!)")
        return
    }

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

    crypt.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.
    var inFile: String? = "qa_data/pdf/sample.pdf"
    var p7sFile: String? = "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.
    success = crypt.createP7M(inFile, p7mPath: p7sFile)
    if success == false {
        print("\(crypt.lastErrorText!)")
        return
    }

    // Verify the .p7s file and extract the original file from the .p7s. 
    var extractedToFilePath: String? = "qa_output/sample.pdf"
    success = crypt.verifyP7M(p7sFile, destPath: extractedToFilePath)
    if success == false {
        print("\(crypt.lastErrorText!)")
        return
    }

    print("Success!")

}