[WkaymQ48]

Hablando de seoane echale un vistazo a esto:
http://code.google.com/p/secrypt/

Usando las bibliotecas del enlace anterior puedes cifrar texto de la siguiente manera:

Código Delphi [-]
uses SeAES256, SeSHA256, SeStreams;



procedure TfrmMain.btnEncryptClick(Sender: TObject);
var
  Key: TAESKey;
  Stream: TMemoryStream;
  BStream: TBase64Enc;
  AStream: TAESEnc;
begin
  try
    Key:= TAESKey(CalcSHA256(txtPassword.Text));
    Stream:= TMemoryStream.Create;
    try
      BStream:= TBase64Enc.Create(Stream);
      AStream:= TAESEnc.Create(BStream,Key);
      try
        txtPlain.Lines.SaveToStream(AStream);
      finally
        AStream.Free;
        BStream.Free;
      end;
      Stream.Position:= 0;
      txtCipher.Lines.LoadFromStream(Stream);
    finally
      Stream.Free;
    end;
  except
    ShowMessage('Failed to encrypt the message');
  end;
end;

procedure TfrmMain.btnDecryptClick(Sender: TObject);
var
  Key: TAESKey;
  Stream: TMemoryStream;
  BStream: TBase64Dec;
  AStream: TAESDec;
begin
  try
    Key:= TAESKey(CalcSHA256(txtPassword.Text));
    Stream:= TMemoryStream.Create;
    try
      AStream:= TAESDec.Create(Stream,Key);
      BStream:= TBase64Dec.Create(AStream);
      try
        txtCipher.Lines.SaveToStream(BStream);
      finally
        BStream.Free;
        AStream.Free;
      end;
      Stream.Position:= 0;
      txtPlain.Lines.LoadFromStream(Stream);
    finally
      Stream.Free;
    end;
  except
    ShowMessage('Failed to decrypt the message');
  end;
end;

En el ejemplo anterior se usa un formulario con dos botones, dos memos y un edit para la contraseña, pero como colocarlos se desprende del propio codigo (o eso espero )

Saludos