Pascal (Lazarus/Delphi)

RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

See more RSA Examples

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context. 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.PrivateKey,
  Chilkat.Rsa,
  Chilkat.PublicKey;

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

procedure RunDemo;
var
  success: Boolean;
  rsa: TRsa;
  pubkey: TPublicKey;
  plainText: string;
  usePrivateKey: Boolean;
  encryptedStr: string;
  rsa2: TRsa;
  privKey: TPrivateKey;
  originalStr: string;

begin
  success := False;

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

  rsa := TRsa.Create;

  //  First load a public key object with a public key.
  //  In this case, we'll load it from a file.
  pubkey := TPublicKey.Create;
  success := pubkey.LoadFromFile('qa_data/pem/rsa_public.pem');
  if (success = False) then
    begin
      WriteLn(pubkey.LastErrorText);
      Exit;
    end;

  //  RSA encryption is limited to small amounts of data. The limit
  //  is typically a few hundred bytes and is based on the key size and
  //  padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
  //  encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
  plainText := 'Time is an illusion. Lunchtime doubly so.';

  //  Import the public key to be used for encrypting.
  success := rsa.UsePublicKey(pubkey);

  //  To get OAEP padding, set the PkcsPadding property equal to False
  rsa.PkcsPadding := False;
  rsa.OaepHash := 'sha256';

  //  Indicate we'll want hex output
  rsa.EncodingMode := 'hex';

  //  Encrypt..
  usePrivateKey := False;
  encryptedStr := rsa.EncryptStringENC(plainText,usePrivateKey);
  WriteLn(encryptedStr);

  //  -------------------------------------------------
  //  Now decrypt with the matching private key.
  rsa2 := TRsa.Create;

  privKey := TPrivateKey.Create;
  success := privKey.LoadEncryptedPem('qa_data/pem/rsa_passwd.pem','passwd');
  if (success = False) then
    begin
      WriteLn(privKey.LastErrorText);
      Exit;
    end;

  success := rsa2.UsePrivateKey(privKey);

  //  Make sure we have the same settings used for encryption.
  rsa2.PkcsPadding := False;
  rsa2.EncodingMode := 'hex';
  rsa2.OaepHash := 'sha256';

  originalStr := rsa2.DecryptStringENC(encryptedStr,True);

  WriteLn(originalStr);


  rsa.Free;
  pubkey.Free;
  rsa2.Free;
  privKey.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.