ABSTRAKSI: Kata Kunci : ABSTRACT: DES algorithm developed at IBM (International Business Machines) under the leadership of WL Tuchman in 1972. The algorithm is based on the Lucifer algorithm created by Horst Fiestel. The first DES algorithm has 56-bit key length. With this 56-bit key length, DES weak against exhaustive key search attack or by trying all possible keys.
At the end of the project has developed the DES algorithm with the expansion along the 112-bit key. Development is carried out by adding a network fiestel into 4 blocks that were previously only 2 blocks.
At the end of the project has developed the DES algorithm with the expansion along the 112-bit key. Development is carried out by adding a network fiestel into 4 blocks that were previously only 2 blocks.Keyword: Block cipher, DES, decryption, encryption