Tcl

Check for an S/MIME Signing Time

Demonstrates the Chilkat Mime.HasSignatureSigningTime method, which returns whether the signer at a zero-based index included a CMS signingTime signed attribute. The only argument is the signer index; use NumSignerCerts for the count.

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: A signing time records when the signer claims to have signed, which matters for auditing and for validating a certificate that has since expired. It is an optional signed attribute, so not every signature has one — this predicate lets you check before calling GetSignatureSigningTimeStr, avoiding an error for signers that omitted it. Being a signed attribute, it is covered by the signature and cannot be altered undetected.

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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, check whether each signer included a CMS signingTime signed attribute.  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} {
    if {CkMime_HasSignatureSigningTime $mime $i} then {
        puts "Signer $i included a signing time."
    }     else {
        puts "Signer $i did not include a signing time."
    }

}

delete_CkMime $mime