Go

CoSign PKCS7/CMS Signed Data

See more Digital Signatures Examples

Demonstrates how to add a 2nd signature to a CMS SignedData. This is to add an additional signature, SignerInfo and certificate(s) to an existing CMS signed data.

In this example, we cosign an existing pdf.p7s

Note: The CoSign method is added in Chilkat v9.5.0.89.

Go

    success := false

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

    crypt := chilkat.NewCrypt2()
    cert := chilkat.NewCert()

    // If loading from a smart card, set the smartcard PIN.
    cert.SetSmartCardPin("0000")

    // Load a certificate in some way, such as from a smart card.
    // Chilkat provides other methods to load from a .pfx, .pem, or from the Windows certificate stores..
    success = cert.LoadFromSmartcard("")
    if success == false {
        fmt.Println(cert.LastErrorText())
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        return
    }

    success = crypt.SetSigningCert(cert)
    if success == false {
        fmt.Println(crypt.LastErrorText())
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        return
    }

    // Load the file to be co-signed.
    // NOTE:  This is to cosign a PDF file contained within a CMS (PKCS7) message.
    // (In other words, the PDF is contained within the CMS SignedData, rather than the other way around
    // where a CMS signature is contained within a PDF.  Use Chilkat's PDF class to sign a PDF, which is
    // to embed a CMS signature within the PDF.)
    bd := chilkat.NewBinData()
    success = bd.LoadFile("qa_data/p7s/cosign/sample.pdf.p7s")
    if success == false {
        fmt.Println("Failed to load pdf.p7s input file.")
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        bd.DisposeBinData()
        return
    }

    // bd2 will contain the co-signed result.
    bd2 := chilkat.NewBinData()
    success = crypt.CoSign(bd,cert,bd2)
    if success == false {
        fmt.Println(crypt.LastErrorText())
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        bd.DisposeBinData()
        bd2.DisposeBinData()
        return
    }

    success = bd.WriteFile("qa_output/cosigned.pdf.p7s")
    if success == false {
        fmt.Println("Failed to save pdf.p7s output file.")
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        bd.DisposeBinData()
        bd2.DisposeBinData()
        return
    }

    fmt.Println("Success!")

    crypt.DisposeCrypt2()
    cert.DisposeCert()
    bd.DisposeBinData()
    bd2.DisposeBinData()