This paper introduces major topics of cryptography such as basic terminology and encryption methods. It then discusses the two types of encryption algorithms available, which are symmetric and public-key. These two types are compared based on how keys are distributed and implementation. Next, the only known algorithm that is considered perfectly secure, a one-time pad, is discussed and why it is rarely used in spite of its strong security. A chapter devoted to key management follows this. A separate section is devoted to key management, because even if an algorithm is considered tightly secure it becomes weak if the key used with the algorithm is improperly managed. The third chapter is devoted to the Data Encryption Standard(DES), because it is considered one of the strongest algorithms currently available to the public, and marks the beginning of widespread interest in cryptography. Finally, conclusions are made about which type of algorithms are strong and what implementations they are best suited for. A reiteration on the management of keys is included in this final section.