Алгоритм кодирования RSA

procedure TForm1.Button3Click(Sender: TObject);
var
  x:string;
  w:int64;
  k:longint;
  ww:char;
begin
  form1.Memo4.Clear;
  form1.memo3.Lines.LoadFromFile('c:\\code_file.txt');
 
  for k:=0 to memo3.Lines.Count-1 do
    begin
      x:=memo3.Lines.Strings[k];
      w:=trunc(exp(strtofloat(s6)*ln(strtofloat(x)))) mod trunc(strtofloat(s5));
      ww:=Chr(w);
      form1.Memo4.Lines.Add(ww);
    end;
end;

...
const
 pk=5; //e
 sk=317; //d
 n1=437; //n
...
//Шифровка
procedure TForm1.Button2Click(Sender: TObject);
var
x:string;
k,q:longint;
w:int64;
 
begin
form1.Memo2.Clear;
 for k:=0 to memo1.Lines.Count do
  begin
   x:=memo1.Lines.Strings[k];
    for q:=1 to length(x) do
      begin
       w:=trunc(exp(pk*ln(strtoint(inttostr(ord(x[q])))))) mod n1;
       memo5.Text:=memo5.Text+inttostr(ord(x[q]))+',';
       form1.Memo2.Lines.Add(inttostr(w));
      end;
  end;
end;
 
//Дешифровка
procedure TForm1.Button3Click(Sender: TObject);
var
x:string;
m1,m2,w:longint;
k,j:longint;
ww:char;
 
begin
 form1.Memo4.Clear;
 form1.memo3.Text:=form1.Memo2.Text;
 
  for k:=0 to memo3.Lines.Count-1 do
   begin
     m1:=1;
     x:=memo3.Lines.Strings[k];
      m2:=strtoint(x);
     for j:=2 to sk do
       begin
        m1:=m1*m2;
        m1:=m1 mod n1;
       end;
     //w:=m2 mod n1;
     memo6.Text:=memo6.Text+inttostr(m1)+',';
     w:=m1;
     ww:=Chr(w);
     form1.Memo4.Lines.Add(ww);
   end;
end;

var
pbuf:tstringstream;
buflen:dword;
pass:ansistring;
begin
CryptAcquireContext( @RSA, PWideChar('my_container'), nil, PROV_RSA_FULL, 0 );
CryptGenKey(RSA, AT_KEYEXCHANGE, (1024 shl 16) or CRYPT_EXPORTABLE, @ExchangeKey);
//
pass := 'password';
CryptCreateHash(RSA, CALG_SHA, 0, 0, RSA_Hash);
  try
  CryptHashData(RSA_Hash, PByte(pass), Length(pass), 0);
  CryptSignHash(RSA_Hash, AT_KEYEXCHANGE, nil,0,nil,@buflen);
  finally
  CryptDestroyHash(RSA_Hash);
  end;
//
pbuf := tstringstream.Create;
CryptExportKey(ExchangeKey, 0, PUBLICKEYBLOB, 0, nil, @buflen);
pbuf.SetSize(buflen);
CryptExportKey(ExchangeKey, 0, PUBLICKEYBLOB, 0, PByte(pbuf.Memory), @buflen);
pbuf.Seek(0, soBeginning);
pbuf.SaveToFile('public.key');
pbuf.Free;
 
pbuf := tstringstream.Create;
CryptExportKey(ExchangeKey, 0, PRIVATEKEYBLOB, 0, nil, @buflen);
pbuf.SetSize(buflen);
CryptExportKey(ExchangeKey, 0, PRIVATEKEYBLOB, 0, PByte(pbuf.Memory), @buflen);
pbuf.Seek(0, soBeginning);
pbuf.SaveToFile('private.key');
pbuf.Free;
//
CryptDestroyKey(ExchangeKey);
CryptReleaseContext( RSA, 0 );
end;
 
Далее импортирую приватный ключ (публичный внутри него)
 
var
pbuf:tstringstream;
i,buflen:dword;
begin
if not FileExists(APP_PATH + 'private.key') then Exit;
CryptAcquireContext( @RSA, PWideChar('my_container'), nil, PROV_RSA_FULL, 0 );
pbuf := tstringstream.Create;
pbuf.LoadFromFile('private.key');
buflen := pbuf.Size;
if CryptImportKey(RSA,PByte(pbuf.Memory),buflen,0,0,@ExchangeKey) then
  begin
  pbuf.Free;
  pbuf := tstringstream.Create;
  CryptExportKey(ExchangeKey, 0, PUBLICKEYBLOB, 0, nil, @buflen);
  pbuf.SetSize(buflen);
  CryptExportKey(ExchangeKey, 0, PUBLICKEYBLOB, 0, PByte(pbuf.Memory), @buflen);
  pbuf.Free;
  pbuf := tstringstream.Create;
  CryptExportKey(ExchangeKey, 0, PRIVATEKEYBLOB, 0, nil, @buflen);
  pbuf.SetSize(buflen);
  CryptExportKey(ExchangeKey, 0, PRIVATEKEYBLOB, 0, PByte(pbuf.Memory), @buflen);
  pbuf.Seek(0, soBeginning);
  pbuf.Free;
  CryptDestroyKey(ExchangeKey);
  CryptReleaseContext( RSA, 0 );
  end;
end;