(Delphi ActiveX) Encrypt/Decrypt using PFX to produce -----BEGIN PKCS7----- ... -----END PKCS7-----

First we encrypt using a certificate + public key to produce output such as:

-----BEGIN PKCS7-----
MIIHPwYJKoZIhvcNAQcEoIIHMDCCBywC ...
...
...
-----END PKCS7-----

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: TChilkatCrypt2;
cert: TChilkatCert;
success: Integer;
toBeEncrypted: WideString;
encryptedStr: WideString;
sb: TChilkatStringBuilder;
outStr: WideString;
bCrlf: Integer;
decrypt: TChilkatCrypt2;
decryptedText: WideString;

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

crypt := TChilkatCrypt2.Create(Self);

// Specify the encryption to be used.
// "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped) message.
crypt.CryptAlgorithm := 'pki';
crypt.Pkcs7CryptAlg := 'aes';
crypt.KeyLength := 128;
crypt.OaepHash := 'sha256';
crypt.OaepPadding := 1;

// A certificate is needed as the encryption key.
// Althought the PFX contains the associated private key, we don't need it for encryption.
// (A certificate usually contains the public key by default.)
cert := TChilkatCert.Create(Self);
success := cert.LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
if (success <> 1) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

// Tell the crypt object to use the certificate.
crypt.SetEncryptCert(cert.ControlInterface);

toBeEncrypted := 'This string is to be encrypted.';

// Get the result in multi-line BASE64 MIME format.
crypt.EncodingMode := 'base64_mime';

encryptedStr := crypt.EncryptStringENC(toBeEncrypted);
if (success <> 1) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// Make a "-----BEGIN PKCS7-----" ... "-----END PKCS7-----" sandwich...
sb := TChilkatStringBuilder.Create(Self);
sb.AppendLine('-----BEGIN PKCS7-----',1);
sb.Append(encryptedStr);
sb.AppendLine('-----END PKCS7-----',1);

outStr := sb.GetAsString();

Memo1.Lines.Add(outStr);

// Sample output:

// -----BEGIN PKCS7-----
// MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix
// GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR
// Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0
// aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug
// DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL
// 8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl
// V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/
// 0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/
// tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V
// k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4
// JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=
// -----END PKCS7-----

// ----------------------------------------------------------------------------------------
// Let's Decrypt the above string.

// Start with what was produced above..
sb.Clear();
bCrlf := 1;
sb.AppendLine('-----BEGIN PKCS7-----',bCrlf);
sb.AppendLine('MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix',bCrlf);
sb.AppendLine('GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR',bCrlf);
sb.AppendLine('Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0',bCrlf);
sb.AppendLine('aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug',bCrlf);
sb.AppendLine('DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL',bCrlf);
sb.AppendLine('8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl',bCrlf);
sb.AppendLine('V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/',bCrlf);
sb.AppendLine('0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/',bCrlf);
sb.AppendLine('tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V',bCrlf);
sb.AppendLine('k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4',bCrlf);
sb.AppendLine('JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=',bCrlf);
sb.AppendLine('-----END PKCS7-----',bCrlf);

decrypt := TChilkatCrypt2.Create(Self);
decrypt.CryptAlgorithm := 'pki';

// Use the same cert + private key from the PFX above.
// For decryption, we need the private key.  Given that the certificate was loaded from a PFX,
// we should already have it.
success := decrypt.SetDecryptCert(cert.ControlInterface);

decrypt.EncodingMode := 'base64';
decryptedText := decrypt.DecryptStringENC(sb.GetBetween('-----BEGIN PKCS7-----','-----END PKCS7-----'));

Memo1.Lines.Add(decryptedText);
end;