Pascal (Lazarus/Delphi)

Encrypt File to PKCS7 .p7m

See more Encryption Examples

_LANGUAGE_ example to public-key encrypt a file creating a PKCS#7 .p7m file as output. Also demonstrates how to decrypt the .p7m to recover the original file. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Cert,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  crypt: TCrypt2;
  encryptCert: TCert;
  inFile: string;
  outFile: string;
  decrypt: TCrypt2;
  pfxFilename: string;
  pfxPassword: string;

begin
  success := False;

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

  crypt := TCrypt2.Create;

  //  Indicate the public-key encryption is to be used.
  //  Do this by setting the encryption algorithm equal 
  //  to "PKI" (an acroynm for public-key infrastructure).
  crypt.CryptAlgorithm := 'PKI';

  //  Indicate the inner symmetric encryption algorithm to be used.
  //  possible values are "aes", "des", "3des", and "rc2".
  //  For this example, we'll use 256-bit AES encryption.
  crypt.Pkcs7CryptAlg := 'aes';
  crypt.KeyLength := 256;

  //  To encrypt, only a certificate w/ public key is needed.
  //  (The certificate w/ private key is required for decryption.)

  //  The LoadFromFile method can load virtually any certificate format:
  //  1. DER encoded binary X.509 (.CER)
  //  2. Base-64 encoded X.509 (.CER)
  //  3. Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)
  //  4. PEM format
  encryptCert := TCert.Create;
  success := encryptCert.LoadFromFile('/Users/chilkat/testData/cer/acme.cer');
  if (success <> True) then
    begin
      WriteLn(encryptCert.LastErrorText);
      Exit;
    end;

  //  Tell the crypt object to use the certificate for encrypting:
  crypt.AddEncryptCert(encryptCert);

  //  Encrypt a file, producing a .p7m as output.
  //  The input file is unchanged, the output .p7m contains the encrypted
  //  contents of the input file.
  inFile := '/Users/chilkat/testData/pdf/sample.pdf';
  outFile := '/Users/chilkat/testData/p7m/sample.pdf.p7m';
  success := crypt.CkEncryptFile(inFile,outFile);
  if (success <> True) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  //  For demonstration purposes, a different instance of the object will be used
  //  for decryption.
  decrypt := TCrypt2.Create;

  //  To decrypt, the certificate w/ private key is required.  A PFX (also known
  //  as PKCS#12) is a common secure container for certs and private keys.
  pfxFilename := '/Users/chilkat/testData/pfx/acme.pfx';
  pfxPassword := 'secret';

  //  Tell the component to look in the PFX file for certs and private keys.
  success := decrypt.AddPfxSourceFile(pfxFilename,pfxPassword);
  if (success <> True) then
    begin
      WriteLn(decrypt.LastErrorText);
      Exit;
    end;

  //  Tell the decrypt object that PKI (public key encryption) is to be used
  //  for decryptiong.
  decrypt.CryptAlgorithm := 'PKI';
  //  There is no need to set the Pkcs7Alg or KeyLength because this information
  //  is contained within the .p7m

  //  Decrypt the .p7m
  inFile := '/Users/chilkat/testData/p7m/sample.pdf.p7m';
  outFile := '/Users/chilkat/testData/pdf/recovered.pdf';
  success := decrypt.CkDecryptFile(inFile,outFile);
  if (success = False) then
    begin
      WriteLn(decrypt.LastErrorText);
      Exit;
    end;

  WriteLn('Success!');


  crypt.Free;
  encryptCert.Free;
  decrypt.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.