(Delphi DLL) Send Encrypted Email using RSAES-OAEP with AES-128 CBC and SHA256

Demonstrates how to send encrypted email using RSAES-OAEP with SHA256 and AES-128 content encryption.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, MailMan, Cert, Email;

...

procedure TForm1.Button1Click(Sender: TObject);
var
cert: HCkCert;
success: Boolean;
email: HCkEmail;
mailman: HCkMailMan;

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

// Load an RSA-based certificate.
// (Encrypting an email only requires the public key.  Decrypting an email requires the private key.)
cert := CkCert_Create();
success := CkCert_LoadFromFile(cert,'qa_data/rsaes-oaep/cert.pem');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

email := CkEmail_Create();

// Create a simple email.
CkEmail_putSubject(email,'Sample RSAES-OAEP Encrypted Email');
CkEmail_putBody(email,'Sample RSAES-OAEP Encrypted Email');
CkEmail_putFrom(email,'support@chilkatsoft.com');

// Add a recipient.
// (The email is encrypted using the recipient's certificate.
// If sending to multiple recipients, then the AddEncryptCert method would
// need to be called once for each recipient's certificate.)
CkEmail_AddTo(email,'Chilkat GMail','chilkat.support@gmail.com');

// Set the email object properties to indicate the desired encryption.
CkEmail_putPkcs7CryptAlg(email,'aes');
// If AES-256 is desired, set the following property to 256.
CkEmail_putPkcs7KeyLength(email,128);
CkEmail_putOaepPadding(email,True);
// Other choices for the OAEP hash algorithm are "sha1", "sha384", and "sha512"
CkEmail_putOaepHash(email,'sha256');

// Provide the certificate to be used for encryption
CkEmail_AddEncryptCert(email,cert);

// Don't forget to indicate that the email should be encrypted when sent..
CkEmail_putSendEncrypted(email,True);

// The mailman object will do the RSAES-OAEP encryption when sending.
mailman := CkMailMan_Create();

// Set the SMTP settings for your email account on your mail server.
CkMailMan_putSmtpUsername(mailman,'SMTP_LOGIN');
CkMailMan_putSmtpPassword(mailman,'SMTP_PASSWORD');
CkMailMan_putSmtpHost(mailman,'MY_SMTP_DOMAIN_OR_IP');
CkMailMan_putSmtpPort(mailman,587);
CkMailMan_putStartTLS(mailman,True);

// Send the email.  The mailman will encrypt the email as directed by the 
// property settings of the email object.
success := CkMailMan_SendEmail(mailman,email);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMailMan__lastErrorText(mailman));
    Exit;
  end;

success := CkMailMan_CloseSmtpConnection(mailman);
if (success <> True) then
  begin
    Memo1.Lines.Add('Connection to SMTP server not closed cleanly.');
  end;

Memo1.Lines.Add('Mail Sent!');

// -----------------------------------------------------------
// This is an example of an RSAES-OAEP encrypted email
// -----------------------------------------------------------

// MIME-Version: 1.0
// Date: Thu, 27 Apr 2017 08:43:32 -0500
// Message-ID: <772DC039F0259C474BAC60240EA2BA2272402308@CHILKAT13>
// Content-Type: application/pkcs7-mime; name="smime.p7m"; smime-type="enveloped-data"
// Content-Transfer-Encoding: base64
// X-Priority: 3 (Normal)
// Subject: Sample RSAES-OAEP Encrypted Email
// From: support@chilkatsoft.com
// To: "Chilkat GMail" <chilkat.support@gmail.com>
// Content-Disposition: attachment; filename="smime.p7m"
// 
// MIICWQYJKoZIhvcNAQcDoIICSjCCAkYCAQAxggGgMIIBnAIBADB1MGgxCzAJBgNVBAYTAlVTMQsw
// CQYDVQQIDAJJTDEQMA4GA1UEBwwHV2hlYXRvbjEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQ
// dHkgTHRkMRcwFQYDVQQDDA5DaGlsa2F0V2lkZ2V0cwIJAMRwugDmvniwMBwGCSqGSIb3DQEBBzAP
// oA0wCwYJYIZIAWUDBAIBBIIBABr0E1dKJjK0FAYRz/NCtJmBeB0nUxgcuBnhGPI/UeyGub3cCo+K
// G5F4/iVTBJqVvYIF5+fvBnyTginwv7OiUiFWLyihiFC3NIyZJO22+XMHpNatCffTPZk10WswkTgk
// G3ApnRvGQAaldnFD0Hs8drPU4vBvY9QsjT7YDGa6u2NMX+sr1ewEZArqU0mNfJ6RsEYd5FQbFEVF
// qLmnz8Dt+yhoJlUtfUd8TXIeqHRJ7RxKOTSzlBZaAdTv2QX4oL9IcAgZeTg5iw+yRPkSAwWyg+I/
// 7fybLsUpRGDHTGUU+AvHvP0kYKa1mkvccBVEC/+4hEyhpS1tWIR5ByY6vM76Z+8wgZwGCSqGSIb3
// DQEHATAdBglghkgBZQMEAQIEEKqD0YDHX1NsVDaV32UczpeAcLteQyRPTV4hATjwcPiVelPfeWNs
// xZKRGaEBqLM8+Y+V4ciCFoOlgJuOcP4m1PTHyilfzd+SCsKz5l1C7+sfPf36n2aacX6IWga59Bz5
// QbWrOHDUT7O5PnGwKVgQFw3Cj4GrdPGWKcoqxB0HuKnj3WA=

CkCert_Dispose(cert);
CkEmail_Dispose(email);
CkMailMan_Dispose(mailman);

end;