An algorithm is considered computationally secure if it can not be broken with standard resources, either current or future. In this paper we have introduced a new block cipher algorithm named X-MODDES. It is unique independent approach which uses several computational steps along with string of operators and randomized delimiter selections by using some suitable mathematical logic. X-MODDES is specially designed to produce different cipher texts by applying same key on same plain text. Thus a new protocol has been designed to encrypt a given text, which allows a higher level security as compare to MODDES. The Algorithm is successfully implemented on text file, corresponding digital image file and audio file. Here we have also tried to highlight the performance of some well known data algorithms like DES, Triple-DES, AES (Rijndael), MODDES, and compare them with the X-MODDES. Finally it has been proved that X-MODDES is one of the best performing partial symmetric key algorithm among the above mention algorithms particularly for the text message with limited size.