B4X

S/MIME Decrypt using Certificate and Private Key in Apple Keychain

See more Apple Keychain Examples

Decrypts S/MIME using a certificate with private key found in the Apple Keychain. B4X

Dim success As Boolean = False

Dim cert As ChilkatCert
cert.Initialize("cert")

'  Load the certificate to be used for decryption by the Subject Common Name
'  On MacOS and iOS, Chilkat will search the Keychain(s) for the matching certificate.
'  Note: The private key must be present to decrypt.
success = cert.LoadByCommonName("My Cert")
If success = False Then
    Log(cert.LastErrorText)
    Return
End If


Log("Cert has private key: " & cert.HasPrivateKey)

'  Load the MIME to be decrypted.
'  We encrypted using this example:  S/MIME Encrypt using Certificate in Apple Keychain
Dim mime As ChilkatMime
mime.Initialize
success = mime.LoadMimeFile("./encrypted.mime")
If success = False Then
    Log(mime.LastErrorText)
    Return
End If


Log(mime.GetMime)
Log("----")

'  Here's the encrypted MIME:

'  Subject: test
'  SomeHeader: 123
'  Content-Type: application/x-pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"
'  Content-Disposition: attachment; filename="smime.p7m"
'  Content-Transfer-Encoding: base64
'  
'  MIICSwYJKoZIhvcNAQcDoIICPDCCAjgCAQAxggGzMIIBrwIBADCBljCBgTELMAkGA1UEBhMCSVQx
'  EDAOBgNVBAgMB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8xFzAVBgNVBAoMDkFj
'  dGFsaXMgUy5wLkEuMSwwKgYDVQQDDCNBY3RhbGlzIENsaWVudCBBdXRoZW50aWNhdGlvbiBDQSBH
'  MwIQPCWvkSv8oQ7xRmEHJ6TzEDANBgkqhkiG9w0BAQEFAASCAQB3VZvHRE5EWxug7Sckpcz1ucDZ
'  YiTKiqmyPt75MhzNRQLtKFx/jWwlemUwnPMzeu6yutCkZ74Bdn7MBsfDqV3bUz43wAu+fRBteGvF
'  mTc00MfY8L7o8dkpj4AqAOCj4hKQzbSE99GvSzyXcPE2Gm5NrOPtKxqfFqbBRTCb4fBZP84LaL+x
'  rnYfrM4qXTppixyN8iFYCd4maEbMu/GA5o+j0BkDDnx42pILDoAGV/ERyx55Y3Nc2Mhm/cITBMNn
'  g7uS9KPrlYizNaqVu09Hi9jg4gdZaRiTjUqg05tSOk/YqIQxTgfscwSPY92/ewpI6e1EHtLt8Q33
'  gWCbERptSntUMHwGCSqGSIb3DQEHATAdBglghkgBZQMEAQIEENm1AxeXlEMx7p6McjHIj5CAUEQj
'  0GuJ5LnTqiqIjOiwmwNidl1N1TRluxX5vAQvwBuYE6bQK4+i04yn2Av3cucW4kvxgP2Nmni+XgQt
'  aPPKlasaVceEeZ15IYjw77/m3YYn

'  -------------------------------------
'  Decrypt the MIME.
success = mime.DecryptUsingCert(cert)
If success = False Then
    Log(mime.LastErrorText)
    Return
End If


'  -------------------------------------
'  Note: A password dialog may be shown, possibly twice, when accessing the private key.
'  See the following blog post explaining how to suppress the dialog:
'  Suppress Password Dialog when Accessing Private Key in Apple Keychain

'  Show the unencrypted MIME
Log(mime.GetMime)

'  Here's the decrypted MIME

'  Subject: test
'  SomeHeader: 123
'  Content-Type: text/plain
'  
'  This is the body.