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.

integer li_rc
integer li_Success
oleobject loo_Mime
string ls_PfxPassword
oleobject loo_Cert

li_Success = 0

loo_Mime = create oleobject
li_rc = loo_Mime.ConnectToNewObject("Chilkat.Mime")
if li_rc < 0 then
    destroy loo_Mime
    MessageBox("Error","Connecting to COM object failed")
    return
end if
li_Success = loo_Mime.SetBodyFromPlainText("This message will be signed.")
if li_Success = 0 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    return
end if

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

//  SigningHashAlg is the message-digest algorithm.  The default is sha256.
loo_Mime.SigningHashAlg = "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.
loo_Mime.Micalg = "sha-256"
loo_Mime.Protocol = "application/pkcs7-signature"

//  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
loo_Mime.UseXPkcs7 = 0

//  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.
ls_PfxPassword = "myPfxPassword"
loo_Cert = create oleobject
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

li_Success = loo_Cert.LoadPfxFile("qa_data/signer.pfx",ls_PfxPassword)
if li_Success = 0 then
    Write-Debug loo_Cert.LastErrorText
    destroy loo_Mime
    destroy loo_Cert
    return
end if

//  Create the detached signature using the algorithms configured above.
li_Success = loo_Mime.AddDetachedSignature(loo_Cert)
if li_Success = 0 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    destroy loo_Cert
    return
end if

Write-Debug "Signed with SigningAlg=" + loo_Mime.SigningAlg + " SigningHashAlg=" + loo_Mime.SigningHashAlg


destroy loo_Mime
destroy loo_Cert