PureBasic

Specify a Certificate for Encrypted Email

Demonstrates the Chilkat Email.AddEncryptCert method, which explicitly specifies a certificate to use when sending encrypted email. Call it once per recipient certificate; ClearEncryptCerts clears the list. This example loads a recipient certificate, registers it, and enables encrypted sending.

Background: When encrypting to multiple people, each recipient needs to be able to decrypt with their own private key. S/MIME handles this by encrypting the message's one-time content key separately under each recipient's public certificate and including all of those wrapped keys in the message. AddEncryptCert is how you build that recipient list — one call per certificate — giving explicit control over exactly whose certificates are used rather than relying on automatic lookup.

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IncludeFile "CkEmail.pb"
IncludeFile "CkCert.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Demonstrates the AddEncryptCert method, which explicitly specifies a certificate for
    ;  sending encrypted email.  Call it once per recipient certificate.  Use ClearEncryptCerts
    ;  to clear the list.

    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkEmail::setCkSubject(email, "Encrypted email")
    CkEmail::setCkBody(email, "Encrypted to the specified recipient certificate(s).")
    CkEmail::setCkFrom(email, "alice@example.com")
    CkEmail::ckAddTo(email,"Bob","bob@example.com")

    ;  Load a recipient certificate (public key) and add it to the encryption cert list.
    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromFile(cert,"qa_data/certs/recipient.cer")
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkEmail::ckDispose(email)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    success = CkEmail::ckAddEncryptCert(email,cert)
    If success = 0
        Debug CkEmail::ckLastErrorText(email)
        CkEmail::ckDispose(email)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ;  Request encrypted sending.
    CkEmail::setCkSendEncrypted(email, 1)

    Debug "Added the recipient's encryption certificate."

    ;  Note: The path "qa_data/certs/recipient.cer" is a relative local filesystem path,
    ;  relative to the current working directory of the running application.


    CkEmail::ckDispose(email)
    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure