PureBasic
PureBasic
Verify the Digital Signatures on an Email
See more Email Object Examples
Demonstrates the read-only Chilkat Email.SignaturesValid property, which is true when the email was received with one or more digital signatures and all of them validated, indicating the message was not altered. It is only meaningful when ReceivedSigned is true, so this example checks that first.
Background: A valid signature proves integrity — the bytes that were signed are exactly the bytes you received — but that is not the same as trust. A message can carry a perfectly valid signature from a certificate you have no reason to trust (self-signed, expired, or from an unknown issuer). So after confirming
SignaturesValid, an application that needs assurance of who signed should separately examine the signer certificate and its chain (see LastSignerCert).Chilkat PureBasic Downloads
IncludeFile "CkEmail.pb"
Procedure ChilkatExample()
success.i = 0
; Demonstrates the read-only Email.SignaturesValid property, which is true if the email
; was received with one or more digital signatures AND all of them validated (indicating
; the email was not altered). It is only meaningful when ReceivedSigned is true.
email.i = CkEmail::ckCreate()
If email.i = 0
Debug "Failed to create object."
ProcedureReturn
EndIf
success = CkEmail::ckLoadEml(email,"qa_data/eml/signed.eml")
If success = 0
Debug CkEmail::ckLastErrorText(email)
CkEmail::ckDispose(email)
ProcedureReturn
EndIf
If CkEmail::ckReceivedSigned(email) = 1
If CkEmail::ckSignaturesValid(email) = 1
Debug "The signature(s) verified: the email was not altered."
Else
Debug "Signature verification FAILED."
EndIf
Else
Debug "This email was not received with a digital signature."
EndIf
; Note: Paths such as "qa_data/..." are relative local filesystem paths,
; relative to the current working directory of the running application.
CkEmail::ckDispose(email)
ProcedureReturn
EndProcedure