Stream cipher system seems to be one of the best alternatives in order to provide confidentiality and security in an on line and high-speed transmission. Cryptography is required to secure the secret information transmitting over the communication channel. Day by day the importance of security increases due to increase of online transaction processing and e-commerce. As well as encryption / decryption algorithm, randomness characteristics of key sequences prove the strength of the stream cipher.

In this work the Linear Feedback Shift Register (LFSR) is used to produce non binary pseudo random key sequence. The length of the sequence has been enhanced by designing hybrid model using LFSR and Genetic Algorithm (GA). Achieving the length more than the maximum length of LFSR is the primary intention of this work. The statistical tests is conducted to assess the randomness of key sequence generated from hybrid model. Generated key sequences are used as key sequences in cryptographic applications and results are analyzed.

为了在在线和高速传输中提供机密性和安全性，流密码系统似乎是最好的选择之一。需要加密以确保在通信信道上传输的秘密信息的安全。由于在线事务处理和电子商务的增加，安全的重要性日益提高。与加密/解密算法一样，密钥序列的随机性也证明了流密码的强度。

在这项工作中，线性反馈移位寄存器（LFSR）用于产生非二进制伪随机密钥序列。通过使用LFSR和遗传算法（GA）设计混合模型，可以增加序列的长度。实现长度大于LFSR的最大长度是这项工作的主要目的。进行统计测试以评估从混合模型生成的关键序列的随机性。生成的密钥序列在密码应用程序中用作密钥序列，并对结果进行分析。