PKCS7 Decrypt Using .pfx or .p12 Data

Demonstrates how to decrypt MIME using a specifc PFX file (.pfx or .p12) for the source of certificate(s) and private key(s).

Download Chilkat FileAccess ActiveX (freeware)

Download Chilkat MIME ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATFILEACCESSLib_TLB,
    CHILKATMIMELib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
mime: CHILKATMIMELib_TLB.IChilkatMime;
success: Integer;
pfxData: Array of Byte;
fac: TCkFileAccess;
pfxPassword: String;

begin
mime := CoChilkatMime.Create();

success := mime.UnlockComponent('Anything for 30-day trial.');
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

//  Load the MIME
success := mime.LoadMimeFile('encrypted.mim');
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

fac := TCkFileAccess.Create(Self);
pfxData := fac.ReadEntireFile('pfxStore/myPkcs12.p12');

pfxPassword := 'myPassword';
success := mime.DecryptUsingPfxData(pfxData,pfxPassword);
if (success = 0) then
  begin
    Memo1.Lines.Add(mime.LastErrorText);
    Exit;
  end;

//  Display the decrypted MIME:
Memo1.Lines.Add(mime.GetMime());

//  Note: The MIME to be decrypted should look something like this
//  when viewed in a text editor:
//  (Note that the Content-Type is application/x-pkcs7-mime)
//  
Content-Disposition: attachment; filename="smime.p7m"
Content-Transfer-Encoding: base64
Content-Type: application/x-pkcs7-mime;
 name="smime.p7m"
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end;