Tcl

Get an S/MIME Signing Time

Demonstrates the Chilkat Mime.GetSignatureSigningTimeStr method, which returns the CMS signingTime attribute for the signer at a zero-based index, as an RFC 822-style date string in GMT. The only argument is the signer index.

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: This is the timestamp the signer asserted at signing — useful for "when was this signed" audit trails and for evaluating whether the signing certificate was valid at that moment. Because it is a signed attribute, it is tamper-evident. Guard the call with HasSignatureSigningTime, since the attribute is optional. Note it is the signer's claim, not a trusted third-party timestamp.

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Tcl


load ./chilkat.dll

set success 0

set mime [new_CkMime]

set success [CkMime_LoadMimeFile $mime "qa_data/signed.eml"]
if {$success == 0} then {
    puts [CkMime_lastErrorText $mime]
    delete_CkMime $mime
    exit
}

#  After verifying, get the CMS signingTime for each signer that has one, as an RFC 822 date string
#  in GMT.  The only argument is the zero-based signer index.
set success [CkMime_Verify $mime]
if {$success != 1} then {
    puts [CkMime_lastErrorText $mime]
    delete_CkMime $mime
    exit
}

set n [CkMime_get_NumSignerCerts $mime]

for {set i 0} {$i <= [expr $n - 1]} {incr i} {
    #  Only signers that included a signing time have one to retrieve.
    if {CkMime_HasSignatureSigningTime $mime $i} then {
        set signingTime [CkMime_getSignatureSigningTimeStr $mime $i]
        if {[CkMime_get_LastMethodSuccess $mime] == 0} then {
            puts [CkMime_lastErrorText $mime]
            delete_CkMime $mime
            exit
        }

        puts "Signer $i signing time: $signingTime"
    }

}

delete_CkMime $mime