(PureBasic) PKCS7 Encrypt using Multiple Certificates

Encrypts MIME using multiple digital certificates. Calls AddEncryptCert once per certificate, followed by a call to EncryptN. The MIME may be decrypted by any owner of one of the certificates + its associated private key.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCert.pb"
IncludeFile "CkMime.pb"

Procedure ChilkatExample()

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

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

    ; Build a simple MIME message to be encrypted:
    success.i = CkMime::ckAddHeaderField(mime,"Content-Type","text/plain")
    success = CkMime::ckAddHeaderField(mime,"abc","123")
    CkMime::ckSetBody(mime,"This is a test")

    ; A digital certificate is required to create PKCS7 encrypted MIME.
    ; It can come from a variety of sources: .cer file, .pfx file, PEM files,
    ; an in-memory representation, or directly from a Windows
    ; registry-based certificate store.

    ; Load one cert from a .cer file:
    cert1.i = CkCert::ckCreate()
    If cert1.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromFile(cert1,"myCert.cer")
    If success = 0
        Debug CkCert::ckLastErrorText(cert1)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert1)
        ProcedureReturn
    EndIf

    ; Load another cert ...
    cert2.i = CkCert::ckCreate()
    If cert2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromFile(cert2,"anotherCert.cer")
    If success = 0
        Debug CkCert::ckLastErrorText(cert2)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert1)
        CkCert::ckDispose(cert2)
        ProcedureReturn
    EndIf

    ; Tell the MIME object to use these certs for encrypting:
    ; (AddEncryptCert shouldn't fail if we already know it contains
    ; a valid certificate..)
    success = CkMime::ckAddEncryptCert(mime,cert1)
    success = CkMime::ckAddEncryptCert(mime,cert2)

    ; Encrypt the MIME:
    success = CkMime::ckEncryptN(mime)
    If success = 0
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        CkCert::ckDispose(cert1)
        CkCert::ckDispose(cert2)
        ProcedureReturn
    EndIf

    ; Display the MIME:
    Debug CkMime::ckGetMime(mime)

    ; The resulting S/MIME looks something like this:

    ; abc: 123
    ; Content-Disposition: attachment; filename="smime.p7m"
    ; Content-Transfer-Encoding: base64
    ; Content-Type: application/x-pkcs7-mime;
    ;  name="smime.p7m"
    ; 
    ; MIID4QYJKoZIhvcNAQcDoIID0jCCA84CAQAxggNlMIIBgQIBADBpMFUxCzAJBgNVBAYTAlpBMSUw
    ; IwYDVQQKExxUaGF3dGUgQ29uc3VsdGluZyAoUHR5KSBMdGQuMR8wHQYDVQQDExZUaGF3dGUgQ29k
    ; ZSBTaWduaW5nIENBAhB4ouTcAmLszrGi170k1deSMA0GCSqGSIb3DQEBAQUABIIBAKnOPgmISrNH
    ; Hd+zESvH5dl5TvBLCxLuIuH6cuZdowHzCqAUzaYFdn1rp88Vvu2x3s6WOvzje/+dE1x0YjEpeqxd
    ; ufehlb6Jl9ucxSMWARWMxWGxu0eZGJVt+SBBrVddqdtrIU9lVt5rBxkU67P8PxgbwdNCX3qJENRO
    ; P/rvp5ngoCkpIxeGqSkPvWv+CA3IXS8FPs8Sl4HNPiAj3e9RBm2MxI1u4cn1HvgGg8yHgHLMG5JF
    ; LzGsmotSQaqEwq2JtOlkjfOwEI+ZhbWQupj6gen2aGc5sW3J26H1usxtV2TQ7WRRxqnZGmlh20dW
    ; 4lo3kITYI+iapGlJXmrlDYh2CjkwggHcAgEAMIHDMIGuMQswCQYDVQQGEwJVUzELMAkGA1UECBMC
    ; VVQxFzAVBgNVBAcTDlNhbHQgTGFrZSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdv
    ; cmsxITAfBgNVBAsTGGh0dHA6Ly93d3cudXNlcnRydXN0LmNvbTE2MDQGA1UEAxMtVVROLVVTRVJG
    ; aXJzdC1DbGllbnQgQXV0aGVudGljYXRpb24gYW5kIEVtYWlsAhAj50QEWUPwA+jXOiL8sMwXMA0G
    ; CSqGSIb3DQEBAQUABIIBAFQ1cydWC4M9tdgAlCN03kP8eyuXajwT+5ByhOcJhjuCABg7U8w4Rx28
    ; braGqV+TCBxjyMsqD0KcW49VT6ZHMpQ1yN8R72qDsidmfm9w3u0jVgsaaBkTJXMy4COY/3cZWmYG
    ; dL3Qty8uFeQYddytt6UPJpGJZYsrdFG2doe6qHiRtAxxPrd0GmQRcGvxyDdsojkoBlTMbfwaXOI3
    ; xepR/oh60x/3npUCsl2VpNPfo6oZoej6YZGEuz2MvuWvXVhvuqoTqXGwGDgYMxwTbPwklqZiJtsK
    ; r5Ep3NlWAQX8MGWL0H+NC22cqJuqUCL05yqyAv+JMCpZGAwOVb/wiVNjpAIwYAYJKoZIhvcNAQcB
    ; MBkGCCqGSIb3DQMCMA0CAToECA5NAJY12cU+gDgZFUc+nsQUUbiR1GH8iBVLI+XWlja9TXEe1Hzt
    ; NlsOylRVBDzjNxUtX/zC0YR7bs+2Cf4JbyuMOA==


    CkMime::ckDispose(mime)
    CkCert::ckDispose(cert1)
    CkCert::ckDispose(cert2)


    ProcedureReturn
EndProcedure