MIME S/MIME Signing Algorithm Properties

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Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

    success := false

    mime := chilkat.NewMime()
    success = mime.SetBodyFromPlainText("This message will be signed.")
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        return
    }

    //  SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
    //  RSASSA-PSS.
    mime.SetSigningAlg("PKCS1-V1_5")

    //  SigningHashAlg is the message-digest algorithm.  The default is sha256.
    mime.SetSigningHashAlg("sha256")

    //  Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
    //  Content-Type header field.  They are normally set automatically, but can be controlled here.
    mime.SetMicalg("sha-256")
    mime.SetProtocol("application/pkcs7-signature")

    //  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
    mime.SetUseXPkcs7(false)

    //  Load a signing certificate (with private key access) from a PFX.  The PFX password should come
    //  from a secure source rather than being hard-coded.
    pfxPassword := "myPfxPassword"
    cert := chilkat.NewCert()
    success = cert.LoadPfxFile("qa_data/signer.pfx",pfxPassword)
    if success == false {
        fmt.Println(cert.LastErrorText())
        mime.DisposeMime()
        cert.DisposeCert()
        return
    }

    //  Create the detached signature using the algorithms configured above.
    success = mime.AddDetachedSignature(cert)
    if success == false {
        fmt.Println(mime.LastErrorText())
        mime.DisposeMime()
        cert.DisposeCert()
        return
    }

    fmt.Println("Signed with SigningAlg=", mime.SigningAlg(), " SigningHashAlg=", mime.SigningHashAlg())

    mime.DisposeMime()
    cert.DisposeCert()