Check if an Email Was Received Digitally Signed

See more Email Object Examples

Demonstrates the read-only Chilkat Email.ReceivedSigned property, which is true if the email was originally received carrying one or more digital signatures. Knowing a message was signed is separate from knowing the signature checked out, so this example also reads SignaturesValid to report whether the signed content verified.

Background: A digital signature on an email (S/MIME) provides two things: authenticity (it was really sent by the holder of a particular certificate) and integrity (the content was not altered in transit). The sender signs a hash of the message with their private key; the recipient verifies it with the sender's public certificate. ReceivedSigned simply tells you a signature is present — verifying it is a separate step exposed through SignaturesValid.

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    success := false

    //  Demonstrates the read-only Email.ReceivedSigned property, which is true if this
    //  email was originally received with a digital signature.  Use SignaturesValid to
    //  determine whether the signed content actually verified.

    email := chilkat.NewEmail()

    success = email.LoadEml("qa_data/eml/signed.eml")
    if success == false {
        fmt.Println(email.LastErrorText())
        email.DisposeEmail()
        return
    }

    if email.ReceivedSigned() == true {
        fmt.Println("This email was received with a digital signature.")
        if email.SignaturesValid() == true {
            fmt.Println("All signatures are valid.")
        } else {
            fmt.Println("One or more signatures are NOT valid.")
        }

    } else {
        fmt.Println("This email was not signed.")
    }

    //  Note: Paths such as "qa_data/..." are relative local filesystem paths,
    //  relative to the current working directory of the running application.

    email.DisposeEmail()