The objective of this research project is to study the current cryptanalysis attacks on the Data Encryption Standard algorithm (DES), and develop trends for further cryptanalysis attacks. There were many current attempts which tried to break the DKS ciphers ; namely :- Cryptanalysis of the DES ke'y based on Exhaustive search. Trap doors cryptanalysis for the DES S-Doxes.*16-rounds cryptanalysis for the DES ciphertext bits distribution. Cryptanalysis on the DES Key length. Cryptanalysis based on weak, semi-weak, semi-semi weak keys. DES cryptanalysic based on avalanche method. DES ryptanalysis based on complementary property. All them been critically criticized because of their limitation concerning computers time and space. This thesis suggests two additional analytical techniques to be used for analyzing DES ciphers. The first method assumes the DES as a circuit and tries to model its behavior as a boolean function . This modeling technique is partly minimized (specifically the S-Box part), using Quine-McCluskey method. The second attempt tries to deduce the correlation between input and output bits. It is subdivided into two classes. The first test is called interdependency test, which tries to show if there is any relation between plaintext bits and ciphertpxt bits, as well as between key bits and ciphertext bits. The second test is celled Divide & conquer attack, which divide the encipherment key into sub-parts and tries to attack each sub-part individually so the number of trials and time needed to break the DES can be significantly reduced. The various analysis methods being written as Pascal program (version 5.5) running under MSDOS (version 4.01) on IBM compatible personal computer