PureBasic

S/MIME Encrypt .eml without Sending

See more Email Object Examples

Demonstrates how to encrypt an email using the recipient's digital certificate. This example just encrypts, and does not send the email. PureBasic

IncludeFile "CkCert.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkEmail.pb"
IncludeFile "CkMailMan.pb"

Procedure ChilkatExample()

    success.i = 0

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

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

    success = CkEmail::ckLoadEml(email,"c:/temp/email/unencrypted.eml")
    If success = 0
        Debug CkEmail::ckLastErrorText(email)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; The email content is encrypted using AES with a 256-bit key, operating in GCM mode, which provides authenticated encryption.
    CkEmail::setCkPkcs7CryptAlg(email, "aes-gcm")
    CkEmail::setCkPkcs7KeyLength(email, 256)
    CkEmail::setCkOaepPadding(email, 1)
    CkEmail::setCkOaepHash(email, "sha256")
    CkEmail::setCkOaepMgfHash(email, "sha256")

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

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

    CkEmail::setCkSendEncrypted(email, 1)
    CkEmail::ckSetEncryptCert(email,cert)

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

    ; The mailman object applies the encryption by rendering the email according to the instructions (property settings) provided in the email object.
    ; No email is sent.
    mailman.i = CkMailMan::ckCreate()
    If mailman.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkMailMan::ckRenderToMimeSb(mailman,email,sbSmime)
    If success = 0
        Debug CkMailMan::ckLastErrorText(mailman)
        CkEmail::ckDispose(email)
        CkCert::ckDispose(cert)
        CkStringBuilder::ckDispose(sbSmime)
        CkMailMan::ckDispose(mailman)
        ProcedureReturn
    EndIf

    success = CkStringBuilder::ckWriteFile(sbSmime,"c:/temp/encryptedEmail.eml","utf-8",0)
    If success = 0
        Debug CkMailMan::ckLastErrorText(mailman)
        CkEmail::ckDispose(email)
        CkCert::ckDispose(cert)
        CkStringBuilder::ckDispose(sbSmime)
        CkMailMan::ckDispose(mailman)
        ProcedureReturn
    EndIf

    Debug "Success!"


    CkEmail::ckDispose(email)
    CkCert::ckDispose(cert)
    CkStringBuilder::ckDispose(sbSmime)
    CkMailMan::ckDispose(mailman)


    ProcedureReturn
EndProcedure