Tcl

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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Tcl


load ./chilkat.dll

set success 0

set mime [new_CkMime]

set success [CkMime_SetBodyFromPlainText $mime "This message will be signed."]
if {$success == 0} then {
    puts [CkMime_lastErrorText $mime]
    delete_CkMime $mime
    exit
}

#  Load the signing certificate (which must have access to its private key) from a PFX file.
#  The PFX password should come from a secure source rather than being hard-coded.
set pfxPassword "myPfxPassword"
set cert [new_CkCert]

set success [CkCert_LoadPfxFile $cert "qa_data/signer.pfx" $pfxPassword]
if {$success == 0} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkMime $mime
    delete_CkCert $cert
    exit
}

#  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
#  the existing message header fields are transferred to the new outer multipart/signed entity.
set transferHeaderFields 1
set success [CkMime_AddDetachedSignature2 $mime $cert $transferHeaderFields]
if {$success == 0} then {
    puts [CkMime_lastErrorText $mime]
    delete_CkMime $mime
    delete_CkCert $cert
    exit
}

set success [CkMime_SaveMime $mime "qa_output/signed.eml"]
if {$success == 0} then {
    puts [CkMime_lastErrorText $mime]
    delete_CkMime $mime
    delete_CkCert $cert
    exit
}

puts "Detached signature added (headers transferred)."

delete_CkMime $mime
delete_CkCert $cert