(Delphi DLL) Send Encrypted Email with a Selected Algorithm (AES, 3DES, etc.)

Sends an encrypted email using the recipient's digital certificate from a .cer file, and chooses 3DES for the encryption algorithm. (It is also possible to send AES encrypted email w/ 128-bit, 192-bit, or 256-bit encryption simply by setting the Pkcs7CryptAlg and Pkcs7KeyLength properties.)

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
mailman: HCkMailMan;
cert: HCkCert;
success: Boolean;
email: HCkEmail;

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

// The mailman object is used for sending and receiving email.
mailman := CkMailMan_Create();

// Set the SMTP server.
CkMailMan_putSmtpHost(mailman,'smtp.mymailserver.com');

// Load the .cer file into a certificate object.
// When sending S/MIME encrypted email, it is the recipient's
// certificate that is used for encryption.  Only the public key
// is needed to encrypt.  The recipient is the only
// one possessing the private key, and therefore is the only
// one able to decrypt.
cert := CkCert_Create();
success := CkCert_LoadFromFile(cert,'cknotes.cer');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

// Create a new email object
email := CkEmail_Create();

CkEmail_putSubject(email,'This email is encrypted');
CkEmail_putBody(email,'This is a digitally encrypted mail');
CkEmail_putFrom(email,'Chilkat Support <support@chilkatsoft.com>');
success := CkEmail_AddTo(email,'Chilkat Blog','admin@cknotes.com');

// Indicate that the email is to be sent encrypted.
CkEmail_putSendEncrypted(email,True);

// Specify the certificate to be used for encryption.
success := CkEmail_SetEncryptCert(email,cert);

// If desired, specify the encryption algorithm to be used.
// The Pkcs7CryptAlg property can be set to "aes", "des", "3des", or "rc2"
CkEmail_putPkcs7CryptAlg(email,'3des');

// If desired, set the key length (in bits) for the encryption algorithm:
// The possible values allowed depend on the Pkcs7CryptAlg property. 
// For "aes", the key length may be 128, 192, or 256. 
// For "3des" the key length must be 192. 
// For "des" the key length must be 40. 
// For "rc2" the key length can be 40, 56, 64, or 128.
CkEmail_putPkcs7KeyLength(email,192);

success := CkMailMan_SendEmail(mailman,email);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMailMan__lastErrorText(mailman));
  end
else
  begin
    Memo1.Lines.Add('Mail Sent!');
  end;

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

end;