Upgrading from Delphi 2005 to 2010 libeay32.dll

I'm upgrading my program from Delphi 2005 to Delphi 2010. I'm having a problem with RSA functions

The following procedure work's well under D2005, but with D2010 the result is always nil. I allready tried with new version of libeay32.dll

function ReadPrivateKey(AFileName: TFileName): pEVP_PKEY;
var
  keyfile: pBIO;
  a : pEVP_PKEY;
begi开发者_运维问答n
  a := nil;
  keyfile := BIO_new(BIO_s_file());
  BIO_read_filename(keyfile,   PAnsiChar(AFilename));
  result := PEM_read_bio_PrivateKey(keyfile, a, nil, nil);
  if result = nil then
  begin
    raise Exception.Create('Não foi possível ler a chave privada.');
  end;
  BIO_free(keyfile);
end;

Does anyone had this problem? Thanks Sam

You should get a warning W1044 "Suspicious typecast of TFileName to PAnsiChar".

You're typecasting TFileName (which is an alias for string and in Delphi 2010 this is UnicodeString) directly to PAnsiChar. I guess that already BIO_read_filename fails; you don't check the returned value. According to the documentation, it expects UTF8-encoded string, so try encoding it with UTF8Encode:

BIO_read_filename(keyfile, PAnsiChar(UTF8Encode(AFileName)));