Block ciphers are one of the important elementary components in the design of many cryptographic protocols . During the past four decades, along with the development in the field of block ciphers’ design, cryptanalysis of block ciphers has also been considered, seriously. Among the various cryptanalysis methods, that methods which are based on differential-type distinguishers, play an important role in the area of cryptography. In this thesis, we consider two cryptanalytic methods, the impossible differential attack and the biclique attack, both of them use differential-type distinguishers. Also, both of these attacks employ the non-probabilistic chosen-plaintext scenarios to reveal the correct secret-key value. For the impossible differential attack, first, using new impossible differential characteristics, two improved impossible differential attacks are provided for block ciphers Zodiac and 3D. Then, we make a discussion on computational complexity of impossible differential attack. For this purpose, we define a concept, called an ideal attack , and it is proved that the time complexity of such an attack only depends on the number of involved key-bits in the attack. Another cryptanalysis method we have considered in this thesis, is the biclique attack. The biclique attack is one of the most recent cryptanalytic techniques which brings new tools from the area of hash functions to the area of block cipher cryptanalysis, and was first introduced by the best known single-key attacks on the full-round variants of AES. However, since its introduction, biclique attack has been applied to many block ciphers. In this thesis, an extension of the biclique attack is introduced, called non-isomorphic biclique attack . In this technique according to an asymmetric key partitioning we obtain isomorphic groups of bicliques; each of them consists of several non-isomorphic bicliques. This method gives more degrees of freedom (rather than biclique attack) in selecting two sets of key differences, and . So, according to the key schedule and the diffusion layer properties of a block cipher, we can choose them in a way which leads to the longer independent bicliques (as well as less data complexity). Application of non-isomorphic biclique attack on the lightweight block cipher mCrypton is also discussed in this thesis. Keywords: Block cipher, Cryptanalysis, Impossible differential attack, Biclique attack, Asymmetric key partitioning, Computational complexity